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Index:

1- Body Ops: 01- Dynamics 02- Origin 03- Primitive 04- Mesh 0- !hanne" 0#- Body

0$- !onvert 0%- &o"'me 10- (et 11- )ie"d 12- (ermina" 13- *e" 14- +mit

1- ,i'id 1#- Partic"es 1$- .ser 1%- Point 1/- igid

1- Body cope: 20- Body cope

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2- )ie"d Ops:

21- Math 22- Processing 23- Primitive 24- Distance 2- !hanne" 2#- *e" 2$- Partic"e

2- )ie"d cope: 2%- cope

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01- Body Ops Dynamic

AccelerationOverview

Adds a constant or spatially varying acceleration to the Field/velocity, Particle/velocity orPoint/velocity channels of all admitted odies! "he channel chosen for #pdating is determinedin the order listed$ e!g! Field/velocity ta%es precedence over Particle/velocity, and so on!

A constant acceleration defined y the &Acceleration& parameter is added if no accelerationfield is connected to field-input! 'f an acceleration field is connected, on the other hand, a per-cell, per-particle or per-point acceleration is comp#ted from the field, for the Field/velocity,

Particle/velocity or Point/velocity channels, respectively!

(hy )o# *ay +are Ao#t "his Op

"his is how yo# add acceleration d#e to gravity to yo#r fl#id, for one thing!

otes

Only odies with a Dynamic *otion-"ype are evolved y this Op!

Dynamics ParametersAcceleration

The constant force to add. The default value represents the force of gravity in a simulation where

1 worldspace unit equals 1 meter. NOTE that this parameter is ignored if an external acceleration

field is defined by connectingfield-input.

Inputs

body-input

ll dynamic bodies are admitted through this input.

field-inputIf connected! is used as an external acceleration field.

Outputs

body-output

ll bodies encountered in body-inputare passed down through this output! regardless if they were

admitted or not.

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Bo#ndary-ffect

Overview

'ncreases the effect a solid has on fl#ids aro#nd it, modeling a .o#ndary layer. aro#nd theoect! *a%e s#re to apply this earlier than gravity!

otes


Dynamics Parameters

Viscosity

"pecifies the #inemetic viscosity of the fluid that we are attemping to model here$ the greater the

value! the greater the effect. It should have units of metres squared per second.

Inputs

body-input

ll dynamic bodies matching the %ield signature are admitted through this input.

solid-input

The solid body defining the &boundary layer& is admitted through here. NOTE that this input will

soon become a %ieldOp input in the same spirit as many other recent changes' however for the

moment we stic# with the &old style& volume(body input.

Outputs

body-output

ll bodies encountered in body-inputare passed down through this output! regardless if they wereadmitted or not.

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Bo#ndary-ayer

Overview

Adds a friction-li%e effect to the Field/velocity channel of all admitted odies in a certainregion of space!


"his is a nonphysical way of forcing fl#ids to e effected more y neary solids, for eampleletting a moving solid drag more fl#id along with it, even if the fl#id has no viscosity!

otes


"he region where the effect is applied is notlin%ed to any interactions created y the 'nteractBodyOp - instead, the region is entirely defined y the distance-field defined y the FieldOpgraph connected to the distance-fieldinp#t!

"his is not 2yet3 a physically correct operation, #t rather a simple tool to get non-dynamicgeometry to infl#ence fl#ids in a .stic%ier. way!

'f yo# also have gravity in the graph, this operator sho#ld come efore 2aove3 theacceleration operator!

Dynamics Parameters

Strength

)ow strong the blending is! in units of *blend fraction+ per second

Bandwidth

The width *in worldspace units+ of the band around the distance(field,s &surface& wherein the

effect is applied. The &surface& is defined wherever the distance(field is -ero.

Inputs

body-inputThe fluid bodies are fed through the body-input! and are required to match the %ield bodysignature in order to be admitted and evolved by this Op.

velocity-field

elocity field *probably from a solid+ that will be blended into the fluid

distance-field

/istance field used to define the region of effect

mask-field

Optional mas# input for modulating the strength

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Outputs

body-output

dmitted or not! all bodies encountered in body-inputwill be passed down through the body-

output.

B#oyancy

Overview

Adds a #oyant acceleration to the Field/velocity channel of all admitted odies!

otesOnly odies with a Dynamic *otion-"ype are evolved y this Op!

4ettings Parameters

Buoyancy Channel

Name of a %ield(0hannel to scale the acceleration amount

Buoyancy Vector

The world(space direction of the buoyancy acceleration

Inputsbody-input

ll bodies matching the %ield signature will be admitted through this input.

Outputs

body-output


admitted or not.

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+om#st

Overview

Performs vol#metric com#stion calc#lations within all admitted odies!


5sing this Op is the difference etween having #st a smo%e-ody vs! a fire-ody!

otes


+om#stion +riteria Parameters

Ignition Temperature

The minimal values of %ieldtemperature cells required to igniting the combustion process.

Burn ate

)ow much of the %ieldfuel channel is consumed per sec in the cells where combustion is ta#ing

place.

!eat

The amout of heat added to %ieldtemperature per second in the cells where combustion is ta#ing

place.

"#pansion

The amount added to %ieldexpansion(rate per second in the cells where combustion is ta#ing

place.adianceThe amount added to %ieldlight per second in the cells where combustion is ta#ing place.

Inputs

body-input

ll dynamic bodies matching the %ield signature are admitted through this input.

Outputs

body-output


admitted or not.

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Drag

Overview

Adds a constant drag acceleration to the Particle/velocity channel on all admitted odies!

otes


Dynamics Parameters

$rag

The drag coefficient. The greater the coefficient is! the more drag is applied.

Inputs

body-input

ll dynamic bodies matching the 2article signature are admitted through this input.

Outputs

body-output


admitted or not.

Dynamics

Overview

6esolves internal and eternal forces, collisions, and constraints, res#lting in new velocitiesfor each admitted ody!

(hy )o# *ay +are Ao#t "his Op(itho#t this op, no fl#id, rigid-ody, or soft-ody dynamics wo#ld e possile7

otes


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FieldOp graph connected to the distance-fieldinp#t!

Dynamics Parameters

'riction

The coefficient of friction. )igher values mean more frictionBandwidth

The width *in worldspace units+ of the band around the distance(field,s &surface& wherein friction

is applied. The &surface& is defined wherever the distance(field is -ero.

Inputs

body-input

The fluid bodies are fed through the body-input! and are required to match the %ield bodysignature in order to be admitted and evolved by this Op.

distance-field

/istance field used to define the region of frictionmask-field

Optional mas# input for modulating the friction

Outputs

body-output


output.

'nteract

Overview

"his BodyOp ca#ses all odies admitted thro#gh .ody-inp#t-a. to dynamically interact withthe odies admitted thro#gh .ody-inp#t-.! 'nteract, in this contet, means collide with orotherwise physically affect and e affected y!

O"8 "his BodyOp will ecome osolete as the Dynamics Op will handle all dynamic inter-ody interaction$ however when this happens 'nteract will get a#tomatically remapped to 9oinand yo#r graphs will th#s %eep wor%ing with no change re:#ired from yo#!

'np#ts

body-input-a

Bodies interacting with body-input-b&s odies enter thro#gh here

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body-input-bBodies interacting with body-input-b&s odies enter thro#gh here

O#tp#ts

body-output

All odies enco#ntered in body-input-aand body-input-bare passed down thro#gh thiso#tp#t!

Particle-"ransport

Overview

"ransport the Particle-+hannel indicated y the &Position +hannel& parameter along anaritrary direction 2vector3 field!


(ell, yo# proaly don&t care, if all yo# want to do is perform particle-ased transport2advection3, along the ody&s Field/velocity channel 2or Particle/velocity channel3, since this isdone a#tomatically at the start of each time-step, efore the graph evolves any odies!

;owever, there are times when the a#tomatic transport is not eno#gh 2or not what yo# want3!"his Op is designed to let yo# eplicitly set #p yo#r own particle transport stage, or addanother one 2or several3 at some #ser- chosen point2s3 d#ring the time-step!

"ransport 4ettings Parameters

%osition Channel

The name of the 2article(0hannel you intend to transport. This is normally the 2articleposition

channel! if you actually want to transport particle positions. *)owever! anyvector(valued 2article(

0hannel is allowed! which means you could use this Op to alter per(particle 637 color or similarby phrasing the color update problem in terms of physical transport+. The channel must already be

present in the 2article("hape of course.

$irection Channel

/efines the vector(field through which the particles will travel. *The default value being thebody,s own velocity(field+. )owever! if a %ieldOp graph is connected to the direction-fieldinput!

the vector(field defined by that graph overrides the field in this %ield(0hannel.

(ormali)e

Normali-e the vectors found in the direction field *or ,/irection 0hannel,+ before transporting the

particles through it.

Inputs

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body-input

ll bodies matching the 2article signature will be admitted through this input.

direction-field

0onnecting a %ieldOp graph to this input will override the direction( field specified as a %ield(

0hannel in the ,/irection 0hannel, parameter.

displacement-field

The distance along the direction field which the particles are transported *the &displacement&+ isscaled by dt *the length of the current time(step! in seconds+ as long as no displacement-fieldis

connected.

Outputs

body-output


output.

6igid-*esh-Assign

Overview

Assigns a mesh to all admitted rigid odies!

4tepping Parameters

"nabledNo description available.

Inputs

body-input

The 6igid 7odies which may be admitted

mesh-input

The 5esh body which defines the 6igid 7ody,s mes

Outputs

body-output

The resulting bodies are passed down through this output

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4wirl

Overview

Boosts eisting vorticity within the Field/velocity channel of all admitted odies!


4ay yo# have a smo%e, fire 2or even li:#id3 sim#lation which has everything the directorwants ecept it lac%s the swirl and eddies only stronger vortices in yo#r flow can create! "hisOp will oost all the regions of the fl#id flow that have vortices, giving yo# more of this type ofloo%!

otes


4ettings Parameters

Strength

The strength of the vorticity boosting. )igher values mean stronger vortices will form. Too highvalues may start brea#ing up your fluid ( if this happens! increase the ,5ax Timesteps, global

parameter.

Inputs

body-inputThe fluid bodies are fed through the body-input! and are required to match the %ield body

signature in order to be admitted and evolved by this Op.

mask-field

The %ieldOp graph optionally connected to this input is sampled at every %ieldvelocity cell!

where the sampled value is used to scale the ,"trength, parameter.

Outputs

body-output


output.

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02- Body Ops Origin

Body

Overview

A Body signature describes a blank body with no pre-defined shapes or channels. It containsonly the most basic properties !otion-"ype and a tile layout. #ot very useful as-is$ buttypically blank bodies are used to add arbitrary shapes % channels to for storage$ or otherspecial &channel processing& in the time-step graph.

'hannels"here are no pre-defined channels in this signature.

!otion "ype (arameters

Motion Type

Defines if and how the body's state is evolved over time. If a body has evolving state, then it must

survive from one time-step to the next, and thus the body isn't terminated until the end of the

entire simulation. Bodies having a Dynamic, Kinematic and ser !otion-"ype are all evolvingbodies. #on-evolving bodies have nsolved !otion-"ype, as there is no state to evolve and thus,

nothing survives from one time-step to the next.

Dynamic$ %volve both position and velocity state on the body. "his is the normal setting for fully

dynamic fluid, rigid, or soft bodies, or particle systems, etc.

Kinematic$ %volve only the position state on the body. "his is normally used for bodies which

evolve only through passive advection &transport through velocity-fields of other bodies &so-

called 'detail sims graphs', etc. Kinematic bodies do not modify their own velocity information at

all( in fact they often don't even have their own velocity channels, and when they do, they arealways )stolen) from other bodies.

ser$ *tate is evolved, however #aiad ma+es no assumptions about which state that would be, nor

how it evolves. "his !otion-"ype is designed for people doing heavy experimentation orimplementing their own transport and dynamics solvers inside the #aiad framewor+.

nsolved$ "he body has no evolving state and its data must be re-created at the start of everytime-step.

"ile ayout arameters

Cell Scale

mount to scale the dimensions of the cells in the tile layout by. #ote that this parameter does notrepresent the actual worldspace dimensions of the cells, rather it uniformly scales them. "o find

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out the actual worldspace dimensions you have to multiply this parameter by the global parameter)!aster /ell *i0e). "his allows you to set a global cell si0e in worldspace units for the whole

simulation &the )!aster /ell *i0e), and still allow each body to have its own cell-si0e by

changing this parameter. If you later decide to globally upre0 the simulation, you don't have to

find every )/ell *cale) parameter on all the Body1ps that have it, but simply change the )!aster/ell *i0e).

Tile Size"he number of cells along each dimension of each tile in the volume

1utputs

body-output

#o description available.

'ameraOverview

A 'amera signature describes a )* camera body.


Motion Type

Defines if and how the body's state is evolved over time. "his signature is a non-evolving

signature, and so the only accepted !otion-"ype is nsolved, which means there is no state to

evolve and thus, nothing survives from one time-step to the next.

"ransform arameters

Translate

Body-to-worldspace translation

Rotate

Body-to-worldspace rotation

Scale

Body-to-worldspace scale

2iew 3rustum arameters

Near Clip


Far Clip


Aspect Ratio


Angle Of View

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1utputs

body-output


+mp-,ead

Overview

,eads bodies from an +!( file.

!esh bodies read by this op are automatically interpolated in space to the precise current

solver time$ even if no substep +!(s are available though they will help the precision of theinterpolation. (er-verte/ velocities will also be automatically created and stored in the(ointvelocity channel if they do not already e/ist in the imported mesh. #O"+ that the meshinterpolation and automatic velocity calculation will fail if the mesh changes topology.

Body (arameters

ody Na!es

%xpects a white-space separated list of body names which, if encountered in the %! file, will be

read and loaded by this op. "he default argument of 4 is a wildcard representing all bodies stored

in the %!. 5ou can right-clic+ on this parameter to get a context-menu of available body names.

/ache arameters

"M# Cac$e

"he name of the %! file to read bodies from

Fra!e #adding

"he number of 0eroes to padding the frame number by, when expanding to the absolute %!

filename.

Fra!e Offset

1ffset the frame to read by this parameter

Repeat "nd Fra!eIf the frame being read is past the end of the %! se6uence, reads the last available %! instead

of reporting an error.

7orld "ransform arameters

Transfor! #oint%position

"his parameter is not yet enabled

&se 'ocal #oint%(elocity

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!esh Body *ettings arameters

&nit Con(ersion

8escales the imported mesh to meter scale units &if re6uired

Cell Scalemount to scale the dimensions of the cells in the tile layout by. #ote that this parameter does notrepresent the actual worldspace dimensions of the cells, rather it uniformly scales them. "o find

out the actual worldspace dimensions you have to multiply this parameter by the global parameter

)!aster /ell *i0e). "his allows you to set a global cell si0e in worldspace units for the whole

simulation &the )!aster /ell *i0e), and still allow each body to have its own cell-si0e bychanging this parameter. If you later decide to globally upre0 the simulation, you don't have to

find every )/ell *cale) parameter on all the Body1ps that have it, but simply change the )!aster

/ell *i0e).

Tile Size

"he number of cells along each dimension of each tile in the volume

1utputs

body-output

ll bodies loaded from the %! will be passed downstream through this output.

+mp-,ead-Isolated

Overview

,eads a single body from an +!( file.

A mesh body read by this op is automatically interpolated in space to the precise currentsolver time$ even if no substep +!(s are available though they will help the precision of theinterpolation. (er-verte/ velocities will also be automatically created and stored in the(ointvelocity channel if they do not already e/ist in the imported mesh. #O"+ that the meshinterpolation and automatic velocity calculation will fail if the mesh changes topology.

Body (arametersody Na!e

"his parameter is used to specify the name of the body to load from the %! file. 5ou can right-clic+ on this parameter to get a context-menu of available body-names.

/ache arameters

"M# Cac$e

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"he name of the %! file to read bodies from

Fra!e #adding

"he number of 0eroes to padding the frame number by, when expanding to the absolute %!

filename.

Fra!e Offset

1ffset the frame to read by this parameter

Repeat "nd Fra!eIf the frame being read is past the end of the %! se6uence, reads the last available %! insteadof reporting an error.

7orld "ransform arameters

Transfor! #oint%position


&se 'ocal #oint%(elocity


!esh Body *ettings arameters&nit Con(ersion

8escales the imported mesh to meter scale units &if re6uired

Cell Scale

mount to scale the dimensions of the cells in the tile layout by. #ote that this parameter does not

represent the actual worldspace dimensions of the cells, rather it uniformly scales them. "o find





Tile Size


1utputs

body-output

"he single body loaded from the %! will be passed down through this output.

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1ield

Overview

A 1ield signature describes a generic field body.

'hannels

"here are no standard channels defined for field bodies. "he only defined thing is theguarantee that there is in fact a 1ield-hape.


Motion Type


signature, and so the only accepted !otion-"ype is nsolved, which means there is no state toevolve and thus, nothing survives from one time-step to the next.


Cell Scale




)!aster /ell *i0e). "his allows you to set a global cell si0e in worldspace units for the wholesimulation &the )!aster /ell *i0e), and still allow each body to have its own cell-si0e by

changing this parameter. If you later decide to globally upre0 the simulation, you don't have tofind every )/ell *cale) parameter on all the Body1ps that have it, but simply change the )!aster/ell *i0e).

Tile Size


1utputs

body-output


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1ield-1ire

Overview

A 1ield-1ire signature uses only fields to describe a fire body with no free-surface unlikeli3uids which do have a surface. 1ield-1ire bodies are typically fed through a 'ombustBodyOp at some point in the time-step graph. "he 'ombust BodyOp is responsible forcalculting the volumetric combustion necessary for setting the light and e/pansion-rate 1ield-'hannels as described below

'hannels

"he following standard channels are always present in 1ield-4as bodies

Vector1ieldvelocity "he worldspace velocity field of the fluid$ sub5ect to the constraintsimposed by the time-step graph evolving the body for e/ample$ boundary conditions and

incompressibility. Float1ieldtemperature A fire temperature field$ where each cell represents the temperature

of the fluid at that spatial location$ given in 6elvin.

Float1ieldfuel A fire fluid field$ where each cell represents the amount of fuel at that spatiallocation.

Float1ieldlight A fire light field$ where each cell represents the amount of radiance emittedfrom that spatial location. "he radiance is typically created by the 'ombust BodyOp.

Float1ielde/pansion-rate A fire e/pansion field$ where each cell represents the amount ofhot-air e/pansion happening at from that spatial location. "he e/pansion-rate is typicallymodified by the 'ombust BodyOp.

Float1ieldsolid-distance A worldspace signed distance field$ representing the surface andinterior of any collisionsolid ob5ects.

Vector1ieldsolid-velocity "he worldspace velocity field of any collisionsolid ob5ects.


Motion Type

Defines if and how the body's state is evolved over time. If a body has evolving state, then it mustsurvive from one time-step to the next, and thus the body isn't terminated until the end of the

entire simulation. Bodies having a Dynamic, Kinematic and ser !otion-"ype are all evolving

bodies. #on-evolving bodies have nsolved !otion-"ype, as there is no state to evolve and thus,nothing survives from one time-step to the next.




evolve only through passive advection &transport through velocity-fields of other bodies &so-called 'detail sims graphs', etc. Kinematic bodies do not modify their own velocity information at

all( in fact they often don't even have their own velocity channels, and when they do, they are

always )stolen) from other bodies.


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nsolved$ "he body has no evolving state and its data must be re-created at the start of every

time-step.

"ile ayout arametersCell Scale






/ell *i0e).

Tile Size


"ransport arameters

Transport #recision

"he accurary of the particle transport &advection. "his property ranges from 9 to :, where 9results in very low precision and : is very high precision. "he higher the precision, the more

substeps the solver will typically re6uire during transport, resulting in a slightly slower &but more

accurate solve. In general, more precision is usually desired when dealing with fast-movingbodies. *ymptoms that can be alleviated by increasing this property include volume loss, particle

bunching, and spurious lea+ing through collision surfaces.

Ma) Transport Substepsimits the number of substeps the transport solver is allowed to ta+e, regardless of how many the

'"ransport recision' property as+s for. !a+ing this value too low may defeat the purpose of the

'"ransport recision' property.

Dynamics arameters

*nteraction Set

whitespace seperated list of body names that this body will interact;collide against, if

encountered in the Dynamics op. "he asteris+ &4 symbol is a wildcard representing all bodies.

Ti!e Scale

"his parameter is a non-physically-correct )retimer) which changes the flow of time in thetransport solver. 2alues < : results in a global speedup of the fluid flow, without introducing any

new velocities or accelerations into the simulation. 2alues less than : similarly result in a global

slowdown of the fluid flow. se this property with care, as it may does introduce unwanted side-effects, especially at high settings.

Fluid +ensity

"he physical density of the fluid, given in units of mass per volume &in *I units$ +g;m=>. #1"%that this global value is overriden by the standard scalar channel 3ield;density &if it exists.

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*ome standard density values &in *I units$

ir$ :

7ater$ :999

Viscosity

"he dynamic viscosity of the fluid, given in units of mass per time per length &in *I units$ +g;&s4m. #1"% that this global value is overriden by the standard scalar channel 3ield;viscosity &if

it exists.

"he fully accurate viscosity in #aiad is cool, but may slow down your simulations significantly, if

you're using the default settings in the Dynamics 1p. If you notice a ma?or slowdown, please

lower the 'recision' parameter on the Dynamics 1p as low as possible while still yielding thedesired viscous fluid behavior.

*ome standard viscosity values &in *I units$

!il+$ 9.>

@oney$ A-:9

!otor 1il$ :-C9

!olten /hocolate$ -:>9

eanut Butter$ A9

1utputs

body-output


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1ield-4as

Overview

A 1ield-4as signature uses only fields to describe a gaseous body. 4aseous bodies are fluidbodies with no free-surface unlike li3uids which do have a surface.

1ield-4as bodies are typically used when simulating gases where 1ield-moke or 1ield-1ireare too specific or overkill for your needs. 7ou can think of 1ield-4as as the starting point fora &build it yourself& gas body$ since all it defines are the most basic channels needed for anygas 5ust velocity % solid collision channels.

'hannels


Vector1ieldvelocity "he worldspace velocity field of the fluid$ sub5ect to the constraintsimposed by the time-step graph evolving the body for e/ample$ boundary conditions andincompressibility.




Motion Type


survive from one time-step to the next, and thus the body isn't terminated until the end of the

entire simulation. Bodies having a Dynamic, Kinematic and ser !otion-"ype are all evolvingbodies. #on-evolving bodies have nsolved !otion-"ype, as there is no state to evolve and thus,





evolve only through passive advection &transport through velocity-fields of other bodies &so-

called 'detail sims graphs', etc. Kinematic bodies do not modify their own velocity information at


always )stolen) from other bodies. ser$ *tate is evolved, however #aiad ma+es no assumptions about which state that would be, nor



time-step.

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Cell Scale


out the actual worldspace dimensions you have to multiply this parameter by the global parameter)!aster /ell *i0e). "his allows you to set a global cell si0e in worldspace units for the wholesimulation &the )!aster /ell *i0e), and still allow each body to have its own cell-si0e by



/ell *i0e).

Tile Size


"ransport arameters

Transport #recision

"he accurary of the particle transport &advection. "his property ranges from 9 to :, where 9results in very low precision and : is very high precision. "he higher the precision, the more

substeps the solver will typically re6uire during transport, resulting in a slightly slower &but more

accurate solve. In general, more precision is usually desired when dealing with fast-movingbodies. *ymptoms that can be alleviated by increasing this property include volume loss, particle

bunching, and spurious lea+ing through collision surfaces.

Ma) Transport Substeps

imits the number of substeps the transport solver is allowed to ta+e, regardless of how many the



Dynamics arameters

*nteraction Set


encountered in the Dynamics op. "he asteris+ &4 symbol is a wildcard representing all bodies.

Ti!e Scale

"his parameter is a non-physically-correct )retimer) which changes the flow of time in thetransport solver. 2alues < : results in a global speedup of the fluid flow, without introducing any



Fluid +ensity"he physical density of the fluid, given in units of mass per volume &in *I units$ +g;m=>. #1"%that this global value is overriden by the standard scalar channel 3ield;density &if it exists.


ir$ :

7ater$ :999

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Viscosity

"he dynamic viscosity of the fluid, given in units of mass per time per length &in *I units$ +g;

&s4m. #1"% that this global value is overriden by the standard scalar channel 3ield;viscosity &if

it exists.


you're using the default settings in the Dynamics 1p. If you notice a ma?or slowdown, please

lower the 'recision' parameter on the Dynamics 1p as low as possible while still yielding thedesired viscous fluid behavior.


!il+$ 9.>

@oney$ A-:9

!otor 1il$ :-C9


eanut Butter$ A9

1utputs

body-output


1ield-moke

Overview

A 1ield-moke signature uses only fields to describe a smoke body with no free-surfaceunlike li3uids which do have a surface.

'hannels


Vector1ieldvelocity "he worldspace velocity field of the fluid$ sub5ect to the constraints

imposed by the time-step graph evolving the body for e/ample$ boundary conditions andincompressibility.

Float1ieldtemperature A smoke temperature field$ where each cell represents thetemperature of the fluid at that spatial location$ given in 6elvin.

Float1ieldsmoke A smoke density field$ where each cell represents the density of smoke atthat spatial location.



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Motion Type


entire simulation. Bodies having a Dynamic, Kinematic and ser !otion-"ype are all evolvingbodies. #on-evolving bodies have nsolved !otion-"ype, as there is no state to evolve and thus,nothing survives from one time-step to the next.








how it evolves. "his !otion-"ype is designed for people doing heavy experimentation or

implementing their own transport and dynamics solvers inside the #aiad framewor+.


time-step.


Cell Scale






/ell *i0e).

Tile Size


"ransport arameters

Transport #recision"he accurary of the particle transport &advection. "his property ranges from 9 to :, where 9

results in very low precision and : is very high precision. "he higher the precision, the moresubsteps the solver will typically re6uire during transport, resulting in a slightly slower &but more

accurate solve. In general, more precision is usually desired when dealing with fast-moving

bodies. *ymptoms that can be alleviated by increasing this property include volume loss, particlebunching, and spurious lea+ing through collision surfaces.



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'"ransport recision' property as+s for. !a+ing this value too low may defeat the purpose of the'"ransport recision' property.

Dynamics arameters

*nteraction Set

whitespace seperated list of body names that this body will interact;collide against, ifencountered in the Dynamics op. "he asteris+ &4 symbol is a wildcard representing all bodies.

Ti!e Scale

"his parameter is a non-physically-correct )retimer) which changes the flow of time in the

transport solver. 2alues < : results in a global speedup of the fluid flow, without introducing any

new velocities or accelerations into the simulation. 2alues less than : similarly result in a globalslowdown of the fluid flow. se this property with care, as it may does introduce unwanted side-

effects, especially at high settings.

Fluid +ensity

"he physical density of the fluid, given in units of mass per volume &in *I units$ +g;m=>. #1"%

that this global value is overriden by the standard scalar channel 3ield;density &if it exists.


ir$ :

7ater$ :999

Viscosity

"he dynamic viscosity of the fluid, given in units of mass per time per length &in *I units$ +g;&s4m. #1"% that this global value is overriden by the standard scalar channel 3ield;viscosity &if

it exists.


you're using the default settings in the Dynamics 1p. If you notice a ma?or slowdown, pleaselower the 'recision' parameter on the Dynamics 1p as low as possible while still yielding thedesired viscous fluid behavior.


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1utputs

body-output


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8air



Motion Type



Cell Scale


Tile Size


1utputs

body-output


!esh

Overview

A !esh signature describes a triangle-mesh body.

'hannels

"he following standard channels are always present in !esh bodies

Vector(ointposition "he worldspace position of each mesh point verte/.

Integer Vector"riangleinde/ "he per-triangle verte/ connectivity.

!otion "ype (arametersMotion Type





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Cell Scale





changing this parameter. If you later decide to globally upre0 the simulation, you don't have tofind every )/ell *cale) parameter on all the Body1ps that have it, but simply change the )!aster/ell *i0e).

Tile Size


1utputs

body-output


(article

Overview

A (article signature describes a generic particle body or 9particle system9 body.

'hannels

"he following standard channels are always present in (article bodies

Vector(articleposition "he worldspace position of each particle.

Vector(articlevelocity "he worldspace velocity of each particle.


Motion Type


survive from one time-step to the next, and thus the body isn't terminated until the end of theentire simulation. Bodies having a Dynamic, Kinematic and ser !otion-"ype are all evolving

bodies. #on-evolving bodies have nsolved !otion-"ype, as there is no state to evolve and thus,


Dynamic$ %volve both position and velocity state on the body. "his is the normal setting for fullydynamic fluid, rigid, or soft bodies, or particle systems, etc.





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ser$ *tate is evolved, however #aiad ma+es no assumptions about which state that would be, norhow it evolves. "his !otion-"ype is designed for people doing heavy experimentation or


nsolved$ "he body has no evolving state and its data must be re-created at the start of everytime-step.


Cell Scale







Tile Size


"ransport arameters

Transport #recision

"he accurary of the particle transport &advection. "his property ranges from 9 to :, where 9

results in very low precision and : is very high precision. "he higher the precision, the more

substeps the solver will typically re6uire during transport, resulting in a slightly slower &but moreaccurate solve. In general, more precision is usually desired when dealing with fast-moving

bodies. *ymptoms that can be alleviated by increasing this property include volume loss, particle

bunching, and spurious lea+ing through collision surfaces.Ma) Transport Substeps




*upersampling arameters

#article Supersa!pling

"he particle density throughout the body, given as a one-dimensional unit. "o get the particle

count per cell in the body's tile-layout, ta+e the cube of this property. 3or example,

supersamplingEA results in F particles per cell &A=>EF.Surface Supersa!pling

"he particle density at the surfaceof the body, where the surface is defined by a distance field &if

one exists -- for example, the article-i6uid body uses the standard 3ield;fluid-distance channelto define the surface of the body. "he common use for this property is to allow a more dense

particle distribution at the surface layer of the body. *ame units as the 'article *upersampling'

property &see above.

Surface andwidt$

"he width of the )surface band) wherein the '*urface *upersampling' property is used to control

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the particle density.

Dynamics arameters

*nteraction Set


encountered in the Dynamics op. "he asteris+ &4 symbol is a wildcard representing all bodies.Ti!e Scale"his parameter is a non-physically-correct )retimer) which changes the flow of time in the

transport solver. 2alues < : results in a global speedup of the fluid flow, without introducing any



1utputs

body-output


(article-:i3uid

Overview

A (article-:i3uid signature uses a mi/ of particles and fields to describe a li3uid body.

'hannels

"he following standard channels are always present in (article-:i3uid bodies

Vector(articleposition "he worldspace position of each particle.

Vector(articlevelocity "he worldspace velocity of each particle.

Vector1ieldvelocity "he worldspace velocity field of the fluid$ mirroring the (articlevelocitychannel. pecifically$ every 1ieldvelocity cell contains a weighted average of every(articlevelocity bounded by the cell$ sub5ect to the constraints imposed by the time-stepgraph evolving the body for e/ample$ boundary conditions and incompressibility.

Float1ieldfluid-distance A worldspace signed distance field$ representing the fluid surface

and interior. pecifically$ the 1ieldfluid-distance channel is guaranteed to match the particledistribution in the sense that where there are particles$ there is also a fluid surface envelopingthose particles and that surface is encoded in this channel.



Float1ieldparticle-count "he number of particles per cell in the body9s tile-layout.

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Motion Type


entire simulation. Bodies having a Dynamic, Kinematic and ser !otion-"ype are all evolvingbodies. #on-evolving bodies have nsolved !otion-"ype, as there is no state to evolve and thus,nothing survives from one time-step to the next.








how it evolves. "his !otion-"ype is designed for people doing heavy experimentation or



time-step.


Cell Scale






/ell *i0e).

Tile Size


"ransport arameters

Transport #recision"he accurary of the particle transport. "his property ranges from 9 to :. "he higher the precision,

the more substeps the solver will typically re6uire during transport, resulting in a slightly slower&but more accurate solve. In general, more precision is usually desired when dealing with fast-

moving bodies. *ymptoms that can be alleviated by increasing this property include volume loss,

particle bunching, and spurious lea+ing through collision surfaces.




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*upersampling arameters

#article Supersa!pling

"he particle density throughout the body, given as a one-dimensional unit. "o get the particle

count per cell in the body's tile-layout, ta+e the cube of this property. 3or example,supersamplingEA results in F particles per cell &A=>EF.

Surface Supersa!pling

"he particle density at the surfaceof the body, where the surface is defined by a distance field &if

one exists -- for example, the article-i6uid body uses the standard 3ield;fluid-distance channel

to define the surface of the body. "he common use for this property is to allow a more denseparticle distribution at the surface layer of the body. *ame units as the 'article *upersampling'

property &see above.

Surface andwidt$

"he width of the )surface band) wherein the '*urface *upersampling' property is used to control

the particle density.

Dynamics arameters

*nteraction Set

whitespace seperated list of body names that this body will interact;collide against, ifencountered in the Dynamics op. "he asteris+ &4 symbol is a wildcard representing all bodies.

Fluid Met$od

"he numerical method used to simulate this fluid body over time.

3I$ %xotic !atter's next-generation implementation of the classic 3luid Implicit article!ethod. "his is the recommended setting for fluids that are very splashy or turbulent.

D%3I$ %xotic !atter's brand new simulation method that produces smoother fluid surfaces

while preserving nearly the same detail as with the 3I method.

Velocity +iffusion

"he amount of numerical diffusion to introduce in the velocity channel. "iny amounts of this canhelp reduce particle noise, which may be beneficial for producing smooth surfaces or ?ust )de-

noise) the particle motion in general. s this parameter ta+es on larger values, the fluid will

appear more viscous. sing this parameter for viscosity will result faster simulation times thanusing the regular 2iscosity dynamics parameter, however the resulting viscosity is not as accurate

as that which is generated by the 2iscosity dynamics property &see below.

Surface Tension

*pecified in standard units of force per unit length &or energy per unit area. "here is a ris+ of the

simulation going unstable if the time step or surface tension are too large or the grid spacing toosmall.

Ti!e Scale

"his parameter is a non-physically-correct )retimer) which changes the flow of time in the

transport solver. 2alues < : result in a global speedup of the fluid flow, without introducing any

new velocities or accelerations into the simulation. 2alues less than : similarly result in a globalslowdown of the fluid flow. se this property with care, as it may does introduce unwanted side-

effects, especially at high settings.

Fluid +ensity

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"he physical density of the fluid, given in units of mass per volume &in *I units$ +g;m=>. #1"%that this global value is overriden by the standard scalar channel 3ield;density &if it exists.


ir$ :

7ater$ :999

Viscosity

"he dynamic viscosity of the fluid, given in units of mass per time per length &in *I units$ +g;

&s4m. #1"% that this global value is overriden by the standard scalar channel 3ield;viscosity &if

it exists.

"he fully accurate viscosity in #aiad is cool, but may slow down your simulations significantly, ifyou're using the default settings in the Dynamics 1p. If you notice a ma?or slowdown, please

lower the 'recision' parameter on the Dynamics 1p as low as possible while still yielding the

desired viscous fluid behavior.


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Fluid Radius Factor

Do #1" change this

1utputs

body-output


,igid-Body



Motion Type


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"et



Motion Type



Cell Scale


Tile Size


1utputs

body-output


;olumeOverview

A ;olume signature encodes a volumetric description of an ob5ect$ storing the ob5ect9sgeometry as an implicit field$ as opposed to e/plicitly reducing the ob5ect into a set of verticesand faces and storing those$ as the !esh signature does.

"he *istance 1ield 'hannel

"he ob5ect is encoded in a signed distance field stored in the 1ielddistance channel which$

like all 1ield-'hannels$ is mapped out across the body9s tile layout.

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fields which #aiad distance-fields also follow is that a negative distance implies the cell liesin the ob5ect9s interior whereas positive distances lie in the e/terior.

'hannels

"he following standard channels are always present in ;olume bodies Float1ielddistance "he worldspace signed distance field of the encoded ob5ect.

Vector1ieldvelocity "he worldspace velocity of the encoded ob5ect.


Motion Type




"ile ayout arametersCell Scale





changing this parameter. If you later decide to globally upre0 the simulation, you don't have tofind every )/ell *cale) parameter on all the Body1ps that have it, but simply change the )!aster

/ell *i0e).

Tile Size"he number of cells along each dimension of each tile in the volume

1utputs

body-output


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03- Body Ops Primitive

Box-Mesh

Overview

Creates an unsolved body using the Mesh signature--meaning vertices are stored in thePoint/position channel and triangle connectivity in the !riangle/index channel" !he geometryis always that o# a unit cube mesh" !he mesh is trans#ormed into worldspace using theparameters #ound in the $!rans#orm$ parameter section"

!he tile layout parameters are provided only because this Op creates a body and thus

re%uires them& however neither the !riangle nor Point-'hape ma(es any use o# the tilelayout"

'ettings Parameters

Body Name

The name of the Mesh body created

Closed Top

Seals off the top face of the box

Closed Bottom

Seals off the bottom face of the box

Transform Parameters

Translate


Rotate


Scale


Tile Layout ParametersCell Scale

Amount to scale the dimensions of the cells in the tile layout by. Note that this parameter does not

represent the actual worldspace dimensions of the cells rather it uniformly scales them. To findout the actual worldspace dimensions you ha!e to multiply this parameter by the "lobal parameter

#Master $ell Si%e#. This allows you to set a "lobal cell si%e in worldspace units for the whole

simulation &the #Master $ell Si%e#' and still allow each body to ha!e its own cell-si%e by

chan"in" this parameter. (f you later decide to "lobally upre% the simulation you don)t ha!e to

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find e!ery #$ell Scale# parameter on all the Body*ps that ha!e it but simply chan"e the #Master$ell Si%e#.

Tile Size

The number of cells alon" each dimension of each tile in the !olume

*utputs

body-output

The mesh body is sent out throu"h this output

'phere-)olume

Overview

Creates an unsolved body using the )olume signature meaning the distance to the sur#aceis stored in *ield/distance and the velocity is stored in *ield/velocity channel" !he sur#ace isalways that o# a unit sphere"

'ettings Parameters

Body Name

The name of the sphere !olume body created

Position

The worldspace center of the sphere

Radius

The worldspace radius of the sphere

Coarsen Interior

This feature is currently disabled

Coarsen Interior Level


Tile Layout Parameters

Cell Scale


represent the actual worldspace dimensions of the cells rather it uniformly scales them. To find

out the actual worldspace dimensions you ha!e to multiply this parameter by the "lobal parameter#Master $ell Si%e#. This allows you to set a "lobal cell si%e in worldspace units for the whole

simulation &the #Master $ell Si%e#' and still allow each body to ha!e its own cell-si%e by

chan"in" this parameter. (f you later decide to "lobally upre% the simulation you don)t ha!e tofind e!ery #$ell Scale# parameter on all the Body*ps that ha!e it but simply chan"e the #Master

$ell Si%e#.

Tile Size


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*utputs

body-output

The sphere !olume body is send down throu"h this output

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04- Body Ops

Box-Mesh

Overview

Creates an unsolved body using the Mesh signature--meaning vertices are stored in thePoint/position channel and triangle connectivity in the !riangle/index channel" !he geometryis always that o# a unit cube mesh" !he mesh is trans#ormed into worldspace using theparameters #ound in the $!rans#orm$ parameter section"

!he tile layout parameters are provided only because this Op creates a body and thusre%uires them& however neither the !riangle nor Point-'hape ma(es any use o# the tilelayout"

'ettings Parameters

Body Name

The name of the Mesh body created

Closed Top

Seals off the top face of the box

Closed Bottom

Seals off the bottom face of the box

Transform Parameters

Translate


Rotate


Scale


Tile Layout ParametersCell Scale


represent the actual worldspace dimensions of the cells rather it uniformly scales them. To findout the actual worldspace dimensions you ha!e to multiply this parameter by the "lobal parameter

#Master $ell Si%e#. This allows you to set a "lobal cell si%e in worldspace units for the whole

simulation &the #Master $ell Si%e#' and still allow each body to ha!e its own cell-si%e bychan"in" this parameter. (f you later decide to "lobally upre% the simulation you don)t ha!e to

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Tile Size


*utputs

body-output

The mesh body is sent out throu"h this output

)istance-Mesh

Overview

!his is a distance-#ield sur#acer op which extracts a triangle-mesh #rom a distance-#ieldsub*ect to various constraints such as collision distance-#ields and mas(s to limit meshingregions etc"

+eneral Parameters

Body Name

The name of the resultin" mesh bod

Surface Supersampling

The amount to supersample the distance-field durin" meshin"

Surface LevelThe iso-!alue of the distance field where the surface is extracte

Mesh Smoothing Steps

The number of laplacian smoothin" iterations performed on the extracted surface mesh.

(nputs

distance-field

The input distance-field that encodes the surface we are meshin"

velocity-field

*ptionally the !elocity field of the surface we are meshin". $onnectin" this input results in the

mesh containin" a per-point !elocity channel which can be used for motion-blur etc.solid-distance-field

*ptionally the solid-distance may be used to constrain the mesh from penetratin" the surface

encoded in this input.

mas-field

*ptionally the mas+-field input is used to determine which re"ions of the distance-field that

should be included in the meshin". Non%ero !alues represent meshable re"ions.

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*utputs

mesh-output

The resultin" mesh is passed out throu"h this body output

Mesh-Merge

Overview

Merges all the Point , !riangle shapes #rom every body admitted through body-inputinto asingle Mesh body" !he resulting merged body is passed out through body-output"

ote that all bodies encountered in body-inputwill be terminated a#ter the merge is complete-- even those bodies which do not match the Mesh signature and were not part o# the #use"

Body Parameters

Body Name


(nputs

body-inputAll bodies matchin" the Mesh si"nature are admitted throu"h here

*utputs

body-output

The resultin" body from the mer"e is passed down throu"h this output

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Particle-Mesh

Overview

!his is a particle sur#acer op that creates a triangle-mesh #rom each admitted body.sParticle/position channel onlyas opposed to the )istance-Mesh op which generates themesh sur#ace #rom a distance-#ield only"

!he Particle/velocity channel i# it exists is used to create per-vertex velocities on the meshstored in the resulting mesh.s Point/velocity channel"

1inally the mas(-#ield input is optionally used to limit the region o# space where sur#acingshould occur"

Body ParametersBody Name


$on!ersion Parameters

Thicening Radius

The thic+ness of each particle used to "enerate the distance-field. A cell in this parameter refers tothe cell-si%e of the tile- layout of the input-body N*T the resultin" !olume. (f the thic+ness is less

than the !olume)s cell-si%e the !olume may be underresol!ed and you may end up with nothin"

or suffer "rid aliasin" artifacts which often end up as a flic+erin" problem.

!etail Band"idth

The amount &in worldspace units' to pad the re"ion of space around the surface of the !olume

used to store the data. ,alues here can cause the tile-layout mappin" the distance-field onto

space to "row allowin" for more freedom in shrin+in"/"rowin" the distance field later on as apost-processin" step.

#nti-Cavity Steps

0ow much to fill in small ca!ities in the resultin" distance-field

Smoothing Steps

0ow much to smooth the resultin" distance-field

Blend Radius $actor

No description a!ailable.

Mesh $luid Smoothing

The number of feature-preser!in" smoothin" steps performed on the extracted surface mesh.

Mesh Blur

The number of non-feature preser!in" smoothin" steps performed on the extracted surface mesh.

$hannel Sweepin" Parameters

Channels

A space-separated list of arbitrary Particle channels to transfer to the mesh &endin" up in the

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Point-Shape'.

%elocity Scale

This con!enience parameter applies a constant scale to the 1ield/!elocity channel of the resultin"

!olume. Be careful when usin" the !olume as a collision body and usin" scales less than 2.

Tile Layout Parameters

Cell Scale

Amount to scale the dimensions of the cells in the tile layout by. Note that this parameter does notrepresent the actual worldspace dimensions of the cells rather it uniformly scales them. To find

out the actual worldspace dimensions you ha!e to multiply this parameter by the "lobal parameter

#Master $ell Si%e#. This allows you to set a "lobal cell si%e in worldspace units for the wholesimulation &the #Master $ell Si%e#' and still allow each body to ha!e its own cell-si%e by

chan"in" this parameter. (f you later decide to "lobally upre% the simulation you don)t ha!e to


Tile Size


$oarsenin" Parameters

Coarsen &nterior


Coarsen &nterior Level


(nputs

body-inputThe bodies containin" the particles to surface

mas-field

*ptionally the mas+-field input is used to determine which re"ions of the distance-field that

should be included in the meshin". Non%ero !alues represent meshable re"ions.

*utputs

body-output

The resultin" meshes are passed out throu"h this body output

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2igid-Mesh-3ssign

Overview

3ssigns a mesh to all admitted rigid bodies"

'tepping Parameters

'nabled

(nputs

body-input

The 3i"id Bodies which may be admitted

mesh-input

The Mesh body which defines the 3i"id Body)s mes

*utputs

body-output

The resultin" bodies are passed down throu"h this output

!et-Mesh

Overview

!et-Mesh extracts the sur#ace mesh #rom the incoming tet body"

+eneral Parameters

Body Name


(nputsbody-input

The tet body we are con!ertin" fro

*utputs

body-output

The resultin" mesh is passed out throu"h this body output

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05- Body Ops Channel

Channel-Filter

Overview

Filters out (erases) channels from a given Shape in all admitted odies!

Filter Settings "arameters

Shape

Specifies which Shape we are filteringFilter

Controls if the channels listed in the 'Channels' parameter are to be erased or kept.

Channels

The space-separated list of channels to keep or erase, depending on the the 'Filter' parameter

setting.

Inputs

body-input

All bodies are admitted through this input

utputs

body-output

All bodies are passed down through this output

Channel-#ename

Overview

#enames a channel in all admitted odies!

$eneral "arameters

Shape

Specifies which Shape to look in for the channel to rename

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Old Channel

Specifies the current name of the channel to rename

New Channel

Specifies the new name of the channel

Inputs

body-input


utputs

body-output


Channel-Split

Overview

Splits off a list of channels into a new ody!

Split Settings "arameters

Shape

Specifies which Shape to look in for the channels to split

ofChannels

A list of names of space-separated channels

Keep Original

!eep the original channels in the bod" after the split

happens.

Inputs

body-input


utputs

body-output


split-body-output

The split bodies are passed down through this output

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Field-Channel

Overview

Creates a new Field-Channel on all admitted odies% and initiali&es it to the value given ythe 'nitial alue' parameter! f the admitted ody doesn't have a Field-Shape% this Op willcreate and add it to the ody efore adding the Field-Channel!

Field *mission (for Smo+e% Fire etc)

,his op can configured to perform Field-Channel emission% such as emitting smo+e into theFieldsmo+e channel inside a Field-$as ody% for instance! ,o ma+e this op wor+ as a fieldemitter% +eep the following in mind.

Set 'alue /ction' to '*mit' so that the Source alue ecomes an emission-rate! se themask-fieldto controlscalemas+ where emission occurs!

se the '#efine ,iles' parameter if you want to e1tend the tile-layout of the ody to cover thetotal region of emission (recommended in most cases)! f you only want emission to occurwhere the ody already has tiles% leave this parameter Off!

2a+e this an 'nterest Channel' if your ody has no particles! 3aiad uses particles todetermine where the fluid is! 4owever% when dealing with pure field odies (such as Field-$asSmo+eFire)% 3aiad trac+s the fluid y e1amining the 'interest channels'% which arepresumed to contain non&ero data in regions where the fluid is defined! ,iles willautomatically e created in those regions% ut only for interest channels! ou should have atleast one interest channel defined!

f you want this channel to e transported along the ody's Fieldvelocity channel (as youwould with smo+e% etc)% set ,imestep pdate parameter to 6ow or 4igh 7etail ,ransport!

,ile-6ayout "arameters

Refine Tiles

#efines the tile la"out of all admitted bodies according to the la"out passed in through the value-

fieldand mask-fieldinputs.

Channel Settings $arameters

Channel

The name of the Field-Channel to create%maintain

Channel TypeThe Field-Channel &alue t"pe. There are two options

Float (ake this a scalar-field channel )a single floating-point &alue per cell*.

+ector (ake this a &ector-field channel ) floating-point &alues per cell*.

Initial Value

The initial constant &alue of the Field-Channel. If the channel is scalar-&alued, onl" the -

component of this &ector is used.

Timestep pdate

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The action taken on the field during the transport stage )at the start of the time-step, before thebodies are e&ol&ed b" the graph*. There are fi&e options to choose from

!eep Current o not modif" the &alues in the channel.

#eset To efault Set all cells to the default &alue )which is e/ual to the 0Initial +alue0

parameter*.

1ow etail Transport Transport the field along the &ector-field found in Field%&elocit" channel.The transport algorithm chosen in this mode is fast but e2hibits more numerical diffusion than the

3igh etail Transport setting.

3igh etail Transport Transport the field along the &ector-field found in Field%&elocit" channel.The transport algorithm chosen in this mode is slower but e2hibits less numerical diffusion than

the 1ow etail Transport setting.

$article Splat Initiali4e the cells in this Field-Channel using a $article-Channel with the same

name as this channel. 5ach cell in the Field-Channel is initiali4ed using the $article-Channel

&alues bounded b" the cell. The 0Splatting (ethod0 parameter controls e2actl" how each

particle's channel &alue contributes to the final cell &alue.

$article Splatting $arameters

Splatting !ethod

Compute the weighted a&erage of all particle channel &alues bounded b" each cell, else 6ustaccumulate the particle channel &alues.

"#tend $oundary

After the splatting, e2tend the &alues of an" boundar" cells into neighboring cells with noparticles. This can be useful when "ou don't want "our field to fade to the background color at the

boundar" of the particle region. ne e2ample of this would be splatting a particle color channel

into a field color channel. If '52tend 7oundar"' was turned off, a halo would form around thecolored region since the ad6acent cells would not ha&e been updated b" an" particles and thus

store some constant background &alue.

Interest Tracking $arameters

Interest Channel

8aiad uses particles to determine where the fluid is. 3owe&er, when dealing with bodies that ha&eno particles )such as Field-9as%Smoke%Fire, etc*, 8aiad tracks the fluid b" e2amining 'interest

channels', which are presumed to contain non4ero data in regions where the fluid is defined. Tiles

will automaticall" be created in those regions, but onl" for interest channels.

Interest Threshold

The minumum &alue in a tile that should be tracked

%istan&e Interest(arks the channel as a distance channel and the 'Interest Threshold' abo&e e/uals the distancefield's iso-surface &alue.

+alue Action $arameters

Run Value '&tion

An e2pression parameter which, if it e&aluates to non4ero, triggers the &alue action to run at the

time this bod" is e&ol&ed b" this p. The &alue action applies the Source +alue to the &alues of

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the channel. The Source +alue is either the &alue of the 'Source +alue' parameter )see below*, orthe contents of the value-fieldinput, if connected. The wa" in which the Source +alue is applied

depends on the '+alue Action' parameter )see below*.

Value '&tion

efines the wa" the Source +alue is used to update the &alues of the channel. This action will notrun unless the '#un +alue Action' e&aluates to non-4ero )see abo&e*.

There are fi&e options to choose from

Set Set channel to the source &alue.

Scale Scale channel b" the source &alue.

Accumulate Add source &alue to the channel.

5mit Add source &alue multiplied b" dt )the length of the time-step* to the channel.

Sour&e Value

The uniform constant source &alue of the &alue action. 8T5 that this parameter is ignored the

value-fieldinput is connected. In that case, the source &alue &aries per cell, and is the &alue of the

Fieldp graph sampled at the each cell position, sub6ect to an" appropriate (AC-grid offsets)e.g., at cell centers for scalar-&alued fields, and on cell faces for &ector-&alued fields*. If the

channel is scalar-&alued, onl" the -component of this &ector is used.

"namics $arameters

%issipation

The rate of dissipation after the &alue-action has been applied to the field. The rate is e2pressed inunits%frame, so a &alue of : means e&er" cell in the channel is reduced to ; in a single frame.

%iffusion

The rate of diffusion after the &alue-action has been applied to the field. The rate is e2pressed inunits%frame.

Inputs

body-input


(alue-field

The Fieldp graph optionall" connected to this input defines the per-cell &alue used b" the &alue-action step )see the '+alue Action' parameter*.

mas)-field

The Fieldp graph optionall" connected to this input defines a mask field which works as a global

scale on the source &alue used b" the &alue-action step )see the '+alue Action' parameter*.

utputs

body-output

All bodies encountered in body-inputare passed down through this output, regardless if the" were

admitted or not.

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Field-3el-Channel

Overview

Computes a channel value for each cell in a field channel of each admitted ody!

,ile-6ayout "arameters

Refine Tiles

#efines the tile la"out of all admitted bodies according to the la"out passed in through the value-

fieldinput.

Channel Settings $arameters

Channel

The channel to create%setChannel Type

The t"pe of the channel.

Channel "#pression

The per-cell field 851 e2pression used to set the channel &alues. If the channel t"pe is scalar

&alued, onl" the component of this parameter is used.

Inputs

body-input

All bodies that match the Field signature are admitted through this input.

(alue-field$ro&ides an optional field which can be sampled in the 851 e2pression

utputs

body-output

All bodies encountered in body-inputare passed down through this output, regardless if the" wereadmitted or not.

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"article-/ge

Overview

Creates a scalar-valued "article-Channel on all admitted odies! ,he channel's name is8age8! ,his Op also performs the actual particle aging% also ta+ing care of +illing particleswho's age reaches or e1ceeds the '6ifespan' parameter!

/ging "arameters

*ifespan

The ma2imum age a particle is allowed to reach before d"ing )in simulation seconds*.

Inputs

body-inputAll bodies that match the $article signature will be admitted

utputs

body-output

All bodies encountered in body-inputare passed down through this output, regardless if the" were

admitted or not.

"article-Channel

Overview

Creates a new "article-Channel on all admitted odies% and initiali&es it to the value given ythe 'nitial alue' parameter!

/lso specifies a value action which determines what happens to the "article-Channel at thetime each ody is evolved y this BodyOp!

f the admitted ody doesn't have a "article-Shape% this Op will create and add it to the odyefore adding the "article-Channel!

Channel Settings "arameters

Channel

The name of the $article-Channel to create%maintain

Channel Type

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The $article-Channel &alue t"pe. There are two options

Float (ake this a scalar channel )a single floating-point &alue per cell*.

+ector (ake this a &ector channel ) floating-point &alues per cell*.

Initial Value

The initial uniform constant &alue of the channel. If the channel is scalar-&alued, onl" the -

component of this &ector is used.

+alue Action $arameters

Run Value '&tion

An e2pression parameter which, if it e&aluates to non4ero, triggers the &alue action to run at the

time this bod" is e&ol&ed b" this p. The &alue action applies the Source +alue to the &alues of

the channel. The Source +alue is either the &alue of the 'Source +alue' parameter )see below*, or

the contents of the value-fieldinput, if connected. The wa" in which the Source +alue is applieddepends on the '+alue Action' parameter )see below*.

Value '&tion

efines the wa" the Source +alue is used to update the &alues of the channel. This action will notrun unless the '#un +alue Action' e&aluates to non-4ero )see abo&e*. There are fi&e options to

choose from

Set Set channel to the source &alue.

Scale Scale channel b" the source &alue.

Accumulate Add source &alue to the channel.

5mit Add source &alue multiplied b" dt )the length of the time-step* to the channel.

Sour&e Value

The uniform constant source &alue of the &alue action. 8T5 that this parameter is ignored if a

Fieldp graph is connected to the value-fieldinput. In that case, the source &alue &aries perparticle, and is the &alue of the Fieldp graph sampled at each particle position. If the channel is

scalar-&alued, onl" the -component of this &ector is used.

Inputs

body-input


(alue-field

The Fieldp graph optionall" connected to this input defines the per-particle &alue used b" the

&alue-action step )see the '+alue Action' parameter*.

mas)-fieldThe Fieldp graph optionall" connected to this input defines a mask field which works as a global

scale on the source &alue used b" the &alue-action step )see the '+alue Action' parameter*.

utputs

body-output

All bodies encountered in body-inputare passed down through this output, regardless if the" wereadmitted or not.

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"article-d

OverviewCreates a 9:-it integer "article-Channel on all admitted odies! ,he channel's name is8id9:8! ,his is a standard "article-Channel which automatically ta+es care of initiali&ing newparticles's id's!

nputs

body-input

/ll odies that match the "article signature will e admitted

Outputsbody-output

/ll odies encountered in body-inputare passed down through this output% regardless ifth

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