Block Model Coding Methods

8/17/2019 Block Model Coding Methods

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Block Model Coding Methods

Presented by: Warren Cook, Mining Systems Analyst, Metech Pty Ltd

INTRODUCTION

Block model coding has become more flexible with the introduction of coding from polygons in a recent version of MineSight3D. It gives the users an alternative to coding from solids. The logic used in polygon coding replicates the logic used inM667V1, which codes the models from VBM data. This paper will discuss the advantages and options available with thepolygon coding option together with some general coding techniques.

MODEL VIEW EDITOR

Block model coding in MineSight is performed from within the Model View Editor and long-time MineSight users will noticesome changes to the format of the Model View Editor. Coding is managed by a combination of the Geometry and CodeModel tabs.

Geometry Tab

The Geometry tab has been re-designed for easier selection and management of polygons and solids. The Geometry sectionof the Geometry tab allows the selection of a Geometry Data object to be used for Model Coding or Exposed Ore display. Anygeometry object present in the Data Manager may be used for coding a model (including linked objects), whether the object isopen or closed in the MineSight viewer.


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Geometry Objects are selected using the Object Contents Browser (OCB)

icon or the Folder Selection icon , both located to the right ofthe Selected Geometry display. A new option that makes loadinggeometry more convenient is the ability to select entire folders from

within a MineSight project. The Folder Selection icon allows the selectionof all geometry (polygons, solids, etc.) within a folder, instead of selectinggeometry from one geometry object at a time. This option will select allgeometry (polygons and surfaces/solids), open or not, from within theselected folder

Below these two icons are the filter options.

.

If only polygons are desired, then turning off the solids filter icon will onlyallow polygons to be selected when using either the OCB or FolderSelection. If both filters are left on then all geometry will be available for

selection. This behaviour is the same for single type geometry objects(polygons or solids) and mixed contents geometry. That is it will still filter an object containing both polygons and solids.


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Production Drilling in MineSight


Objects present in the ‘Selected Geometry Display’ may be removed from a geometry set by highlighting the unwanted object

in the dialog display and clicking the delete button to the right of the OCB icon.

For those users who often code models, you now have the advantage of saving your geometry selection by using the SaveGeometry Set option. This allows the user to quickly and easily reload the same set of geometry for more efficient modelcoding.

Objects present in the ‘Selected Geometry Display’ may be saved as a ‘geometry set’ for quick access during future coding. Setscan be saved by clicking on the Save Geometry Set button. The ‘Save Geometry Set’ dialog will appear. A new set namemay be entered into the text window to the right of ‘Geometry Set Name’. The new set may overwrite an existing set bychoosing a name from the ‘Existing Geometry Set:’ window. Click OK to save the geometry set.


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Saved geometry sets may be deleted using the Delete Geometry Set button. Choose the geometry set to be removed eitherby typing the name into the ‘Current Geometry Set:’ window, or by selecting from the drop down list using the arrow to theright of the ‘Current Geometry Set:’ window. When the unwanted geometry set appears in the ‘Current Geometry Set:’window press the ‘Delete Geometry Set’ button to delete it.

When the Confirm Change not saved/Deleted/Overwrite a set option is toggled ON, a Yes/No warning window isdisplayed which is useful in preventing you from accidentally deleting or overwriting an existing geometry set. If this option is

toggled OFF the warning windows are disabled.

Clicking on the Code model button switches to the Code Model tab, where the various Model codingoptions can be selected. The Code Model tab is also accessed by clicking on the tab at the top of the Model View Editorwindow.

Code Model Tab

The Code Model tab allows you to code items in the model file (file 15) directly from a geometry object: single or multiplegeometry objects consisting of solids or polygons. The geometry objects used for coding are selected on the Geometry tabdialog.

The first option on the Model View Editor Code Model tab is a drop-down list at the top, left-hand corner containing optionsto Code From Solids or From Polygons. If the geometry objects selected on the ‘Geometry’ tab are solids, then ‘CodeFrom Solids’ should be used. Likewise, if the selected geometry objects are polygons, then the option to code ‘From Polygons’should be used. A third option, which is under current development and is ability to code between surfaces.


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The Code Model tab now contains several sub-tab dialogs. The sub-tabs change depending on the coding option selected.

From Polygons

When coding From Polygons is selected, the orientation for coding must be chosen from the drop down box (Benches/ModelXY, EW Sect/Model XZ and NS Sect/Model XZ). The Orientation: drop-down list, located at the top right-hand corner of thedialog, allows you to control which direction the model gets coded. If the polygons are mostly horizontal, then the‘Benches/Model XY’ option should be used. If the selected polygons are vertical, then either the EW or NS section orientationoptions should be used, depending on which way the plane the polygons are oriented.

Below these drop-down boxes are the coding options tabs. It is possible to have a total of five tabs. The first two tab dialogsare available to all coding options (Solids or Polygons). The third is the Items tab, which allows the use of up to 12 total codingitems, and is available when the More Items checkbox on the ‘Coding options’ tab is selected. The last two tabs (Planes and2D Options) are only available when coding From Polygons.


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Coding Options

The entries on this page are divided in two groups – Storing options and Items

• Storing options

There are seven coding option choices when coding with polygons.

1. CODE by majority code

This option codes individual blocks with the material codes of the geometry objects in order of the largestpercentage of a geometry object inside the block. The result is stored into a single item.

For example, geometry objects ‘C’ and ‘D’ have material codes 3 and 4 respectively. Inside a model block,geometry object ‘C’ fills 30% of the volume, while geometry object ‘D’ fills 40% of the volume. The firstblock item selected will be coded 4, because object ‘D’ is the majority code inside model block. If a secondmodel code item is selected, it will be coded 3, because object ‘C’ is the second majority code inside the

model block.

Zone 4

40%

Zone 3

30%


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2. CODEs and PERCENTs in majority order

This option is like the ‘CODE by majority code’ option above, with the addition of a percentage item. Withthis option, the model will code the model code item selected, and the percentage of the block that thegeometry object occupies.

For example, geometry object ‘C’ has a model code of 3. Inside a model block, geometry object ‘C’

occupies 30% of the block. Therefore, the selected ‘Code Item’ will be assigned a code of 3, and the ‘OrePercent Item’ will be assigned 30%.

For example, geometry objects ‘C’ and ‘D’ have material codes 3 and 4 respectively. Inside a model block,geometry object ‘C’ fills 30% of the volume, while geometry object ‘D’ fills 40% of the volume. The firstblock ‘Code Item’ selected will be coded 4 the ‘Ore Percent Item’ will be assigned 40%., because object ‘D’is the majority code inside model block. If a second model code item is selected, it will be coded 3 the ‘OrePercent Item’ will be assigned 30%., because object ‘C’ is the second majority code inside the model block.

3. CODEs and non-zero PERCENTs in codes' order

This option is the same as the 'Codes and Percents in majority order' option above, except that the codesare arranged by code priority order instead of by majority order. Use the button labelled ‘Prioritize Modelcodes’ to change the code priority order. This button is found at the lower left-hand corner of the dialog.

Zone 4

40%

Zone 3

30%


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4. all PERCENTs in codes’ order

This option only codes the percentage of each object contained inside a model block. They are arranged incode priority order.

Zone 4

40%

Zone 3

30%

Zone 4

40%

Zone 3

30%


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5. Total PERCENT within solid(s)/polygon(s)

Only one model item may be updated with this option. The result is the percentage of all selectedgeometry objects within a model block.

For example, inside a model block, geometry object ‘C’ fills 30% of the volume, while geometry object ‘D’fills 40% of the volume. The block ‘Ore Percent Item’ will be assigned 70%., which is the total percentage

that all geometry fills the block.

6. Hangingwall/footwall/interburden (polygons only)

This option is used for evaluating seams, such as multi-layered coal formations, and is only available when

coding From Polygons and when coding a model in vertical section. This option allows one to storepartials of the areas of a block NOT enclosed by a polygon.

Zone 4

40%

Zone 3

30%

Hangingwall

Footwall

Interburden


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When using this option, 3 items are available for coding. The items are coded with a percentage of a blockthat matches the item definition. ‘Hanging wall’ is the area of the block that extends from the topside ofthe block (higher elevation) down to the first geometry object encountered (presumed to be the ore bodyor seam). ‘Footwall’ is the area of a block that extends from the bottom side of the block (lower elevation)up to the nearest geometry object. ‘Interburden’ is the area inside a block that does not touch either upperor lower boundaries, but is sandwiched between two or more geometry objects within one block. If onlyone geometry object is used, then the interburden value will be 0% since there is no area that is not

bordered by the upper or lower boundaries of the block.

7. CODE at block centers (from polygons only)

This option is only available for use when coding ‘From Polygons’. The coding option is the same as ‘CODEby majority order, except the only code applied to model blocks is the code of the object that is positionedat the block center. The result is stored into a single item.

o Min value of majority percent to code block: input window

When coding by majority code, one can specify the minimum value of majority percent to code the block(this value is ignored for other coding options). This option is useful for controlling which blocks get coded.The default value is 1%, but can be as high as 100%. For example, setting the minimum value to 100%means only blocks totally encompassed by the selected geometry objects would be coded or if set to 50%then at least 50% of the geometry must fill the model block.


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o Code entire model checkbox

By default only the current model view range, as set on the Range tab of the Model View Editor, is coded.Toggle on this option to code the entire block model.

o Partial item is WASTE checkbox

This option behaves differently when Coding From Solids and when coding From Polygons. WhenCoding from Solids, it applies when you are storing a single partial. In this case 100% - partial% (or 1 –partial fraction) is stored.

When coding From Polygons, the waste option is available to all storing options (although ignored whenusing Hangingwall/footwall/interburden). The partial area of a block outside polygons is coded based onthe code of the influencing polygon. When coding, slices pierce the model in the selected direction, eitherdown through the block when using vertical slices, or from a higher easting/northing to a lowereasting/northing for horizontal slices. The default direction is horizontal slices, which run in the east/westdirection in plan. Vertical slices may be selected on the 2D Options page by toggling ON the Usevertical slices checkbox. The area directly below an object (the shadow of the selected polygon) isconsidered ‘Waste’.

If set 'Min value of majority percent to codeblock is set to 50 thenthe block on the rightwould get coded but theblock on the left wouldnot.

In this exampleonly a singleblock would becoded


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Using this option, the ‘Waste’, or area below the selected polygon, is coded with the value of theinfluencing polygon. The influence of the polygon code onto the waste applies throughout the entire areaof the model in the shadow, and is only limited by another polygon or the limits selected on the Range tab.

By toggling ON the Partial item is WASTE checkbox and setting the resetting Pct/Partial to 100% youcan code the porportion of the block that is outside of the geometry.

Coding as waste


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o Code Waste from below checkbox

This option is only available when coding From Polygons and is used with the Partial item is WASTEoption described above. Using this option allows the user to force coding the waste (that part of themodel in the ‘shadow’ of the selected polygon) in the opposite direction. (e.g., instead of a polyline codebeing applied to the waste section below, the code will be applied to the waste section above.)

Coding as ore


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o Combine “leftover” partials: drop-down box

If calculating more partials then you are storing (using more objects than ‘Ore Percent Items’), there is theoption to combine leftover partials. The “leftover” (sum of remaining partials) can be added to a majoritypartial, distributed proportionally between partials being reported, or stored to a specified item. The

specified “combine” item can be one of items requested for partials, in which case the “leftover” partial isadded to the corresponding partial. If the “combine” item is a separate item, then the sum of “leftover”partials is just stored in that item. If storing to a specific item, then the item may be selected with the itemselection icon located on the far right side in the ‘Items’ section of the Coding options page.

• Items

This section is where you define which items in the block model will be updated by the coding process.

o Zone checkbox, Code Item and Ore Percent Item selection windows

This area of the dialog is used to select which items of the block model will be updated by the codingprocedure. Some options only allow the use of a single ‘Code Item’ or a single ‘Ore Percent Item’. Otheroptions allow the use of multiple ‘Code Item’ and ‘Ore Percent Item’ selections.

To select an item in either section, use the ‘item selection icon’ to the right of the display window to selectfrom the list of items within the block model. An item is selected for coding when the ‘Zone’ checkbox tothe left of the display window is toggled ON.

When choosing items to code, the item must be checked for suitability. ‘Code Items’ must have the proper

‘Min’ and ‘Max’ values to properly record data from the coding geometry object. Whether a partial isstored as percent or as a fraction of 1 depends on the range of the selected item. If the item’s ‘Max’ valueis greater than 99, the percent is stored, otherwise partials is stored as a fraction of 1. This informationabout each block model item is available on the Info tab of the Model View Properties dialog (alsoknown as the Model View Editor).


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o Reset chosen items before coding to: checkbox and input windows

It may be desired to clear the item information contained in the block model before coding. If the checkboxis toggled ‘on’ then when the model codes all the items selected for coding will be reset to the desiredvalues. These values are adjusted by typing in the input windows below the checkbox. The inputs can beany number that is within the ‘Min’ and ‘Max’ constraints of the selected items, as seen on the ‘Info’ tab ofthe ‘Model View Properties’ dialog. The default is an undefined value, or dash (-). Reset values apply to allCode/Ore items. If the ‘Reset’ value is different from 0 or undefined, it is recommended to have ‘OrePercent Items’ either all percent items or all fraction items.

o “Combine” Item’ item selection icon and window

If calculating more partials then you are storing (using more objects than ‘Ore Percent Items’), there is theoption to combine leftover partials. The “leftover” (sum of remaining partials) can be added to a majoritypartial, distributed proportionally between partials being reported, or stored to a specified item. Thespecified “combine” item can be one of items requested for partials, in which case the “leftover” partial isadded to the corresponding partial. If the “combine” item is a separate item, then the sum of “leftover”partials is just stored in that item. If storing to a specific item, then the item may be selected with the itemselection icon located on the far right side in the ‘Items’ section of the Coding options page.

o More Items checkbox

If more ‘Code Item’ and ‘Ore Percent Item’ selections are required the ‘More Items’ checkbox option can beused. Toggling ON the checkbox, located on the lower right-hand side of the ‘Items’ section of the ‘Codingoptions’ page, will activate a new ‘More Items’ page. This allows the use of nine more block model items,or a total of twelve block model items available for coding.


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Normalize page

On this page one can specify a normalisation calculation for the items to be coded (if desired). Normalisation willguarantee that the sum of all percentage items in a block is not greater than 100%. Percentages totaling more than100 can occur if the solids being used in the model update overlap or intersect. (This could be due to errors indigitising, or to purposeful overlapping due to complex solids.). It can also happen when coding by polygons onepolygon group at a time.

• Normalize: drop-down box

The items can be normalised proportionately or by user-specified priority. If no normalisation is desired, then ‘none’should be selected from the ‘Normalize’ drop down box. If normalised proportionally, then all partials are adjustedbased on the individual items proportion in the block. If normalised by priority/majority, then only thepriority/majority item will be adjusted to make a sum of 100%.

• Normalize against item: item selection icon

Normalise can also be used against an item (item’s value, e.g. TOPO%) to assure that the sum of partials in a blockis not greater then the selected item’s value. (e.g. if only 50% of a block is below the surface elevation, then the sumof the normalised values will not exceed 50%.)

• Normalization tolerance: percentage

When using proportional normalisation there is the option to specify normalisation tolerance. If you do so, and the

sum of partials is within tolerance of 100% (normalisation item’s value) it will be brought to 100% (normalisationvalue).

• Normalisation Examples

1. Simple overlap of two polygons

Two overlapping zones

Polygon C and D overlap by 10%

Polygon C = 70% of Block

Polygon D = 40% of Block

The total block percent is 110% beforenormalisation.


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∗ None

If coding just zones into the model, or when coding percentages and when the zones beingcoded are not near each other, you do not need to select any normalisation.

∗ Proportionally

If the sum of the zone percentages is greater than 100% in a block, then Proportionalnormalisation will downgrade all the percentages equally.

Percentage ResultsPolygon C = (70/110)*(100) = 63.6 %Polygon D = (40/110)*(100) = 36.4 %

∗ By Priority

In this case, the normalisation will remove the excess percentage from the lowest prioritymaterial. The priorities are defined in the Object Properties Materials tab.

Percentage Results - if Priority of Polygon C > Polygon C

Polygon C = 70 %Polygon D = (40 - 10) = 30 %

2. Two adjacent zones with a gap between

The gap is 10% of the block

Polygon C = 50% of Block

Polygon D = 40% of Block

The block percent is 90% before toleranceadjustment.

∗ Proportional Tolerance

The percentage to add is divided proportionally between the solids in the block, based on theiroriginal percentage.

Percentage Results

Polygon C = (50/90)*(100) = 55.5 %

Polygon D = (40/90)*(100) = 44.4 %

∗ Priority defined Tolerance:

The percentage to add is added only to the highest priority solid, based on the priority definedin the Object Properties Materials tab.

Percentage Results - if Priority of Polygon C > Polygon D

Polygon C = (50 + 10) = 60 %

Polygon D = 40 %


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Planes

The Planes page is only available when coding From Polygons. In order to code the model from 2D polygons,either a series of planes or a grid set must be specified.

On the Planes tab, because polygons don’t have volume, the user must define which direction and for what distancethe polygon has influence. Since polygons can be created in any orientation, it allows the user control over whichpolygons are to be used for the coding by setting a tolerance for placing a polygon on a plane. If a polygon is withinthe tolerance limits of the plane, then the projection of the polygon is superimposed onto the plane for propercoding of the model. Any polygon that extends beyond the tolerance will be excluded from the coding opertion.

Planes' selection:

The user must select either a grid set or define plane limits.

o Use Grid checkbox

Toggling ON this option allows the polygons to be coded using an existing grid set.

Grid selection icon

Select an existing grid set by clicking on the grid set selection icon at the right of the page. Any grid setsavailable within the Data Manager may be used. An advantage to using existing grid sets is that thedistance between benches or sections can vary throughout the project. When manually entering planesthe distance between benches or sections must be equal.


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o Plane Selection Limits sub-section

If not using an existing grid set for coding purposes, then the user enter the desired planes manually.Simply enter in the desired ‘Start Plane’ and ‘End Plane’ into the appropriate interactive windows. Thenenter the desired increment between planes in the ‘Increment’ interactive window.

Set planes from model: Set button

Instead of manually entering the plane data into the ‘Start Plane’, ‘End Plane’, and ‘Increment’ windows,the ‘Set’ button can be used to set the planes using the limits defined in the block model file. This optionalso serves as a convenient starting point for setting a personalized plane set within the model boundaries.

o Tolerance for placing polygon on a plane

The 3D polygon selected for coding is projected onto some plane from the above plane set, so that themodel can be coded correctly. The ‘Tolerance’ option is used to specify the distance from the plane apolygon may exist before becoming unacceptable for coding. Only polygons that are completely within‘Tolerance for placing polygon on a plane’ will be used. Polygons that are not completely within tolerancefrom some plane in the selected plane set will be ignored. Any distance may be used, but it is practical anduseful within a relatively small distance from a plane. (e.g., for planes with an increment of 15 meters, 1-5meters normally would be used for the ‘Tolerance’ distance.)

o Ignore planes without selected geometry checkbox

If this option is selected, the planes without projected polygons are removed from the planes set. Thataffects the range of plane influence. If the option remains ‘off’ then the polygon only codes blocks betweenthe plane it is projected onto and the next nearest plane. If the option is toggled ON then the polygoncodes all blocks that are between the plane it is projected onto and the next plane that contains aprojected polygon. This is a convenient option when coding a large portion of a block model with a singlepolygon.

o Bench/ Sections selection: drop-down box

All Benches/Section in the range of influence


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First the range of plane influence is defined. There is an option and a text field that define therange of influence. By default the range extends in both directions from a plane. The maximumextent is halfway between planes. You can change that by toggling an option “Expand fromplane to the next”. In this case the range is from the plane to the next (planes are ordered byincreasing coordinate value). If the distance of influence the above range is used. If a distance ofinfluence is entered into the ‘Distance of influence’ text field, the range is limited by the enteredvalue.

Code only if plane is within a Bench/Section

This option limits the extent of coding only from those planes that fall within a bench or section.Bench heights are set in the block model. When coding from this option, the toe/min sectioncoordinate is included, and the crest/max section coordinate is excluded. If several planes arewithin a bench (section), the plane closest to the bench/section coordinate is used. You can useeither bench toe (minimum section coordinate) or the midblock coordinate for a bench (seebelow the description of a toggle Bench/ Section at midblock coordinate’).

o Bench/ Section at midblock coordinate check box

The default coordinate of a bench or section is the toe value of a bench, or the minimum value of a section.

This option allows one to use the midpoint coordinate as the starting point for coding operations. Thebench (or section) coordinate value is used to determine whether the bench (or section) is within the rangeof influence from the coding plane.

o Expand from plane to the next checkbox

Toggling ‘on’ this option allows one to force the coding to span the entire distance from one plane to thenext.

o Distance of influence

Enter the distance of influence the plane has on coding the block model. Whether you are coding from aplane to the next or halfway between planes, you can limit the range of plane influence by entering apositive distance value.

2D Options page

This page is available only when coding From Polygons.


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The user also has control over how the program computes partials such dealing with overlaps. Slightoverlaps between polygons can be ignored based on a set limit or if there a large overlaps then it would bebetter to code one polygon after the other.

o Tolerance to ignore overlaps

Tolerance to ignore overlaps should be used if polygons are slightly overlapping. Polygons withintolerance will be considered coincident. When coding from polygons (unless coding one polygongroup at a time), partials within overlapping codes are considered “unresolved” and are notreported. Increasing tolerance may reduce the number of unresolved partials. You should exercisecaution, as increasing tolerance too much may alter partials in an undesirable, or unrealistic,manner.

o Number of passes to compute partials

To compute 2D partials, intermediate lines (“slices”) are passed through blocks and report whenintersections with polygons are found. This option allows one to specify the number of intermediatelines to use for coding calculations.

o Use vertical slices checkbox

By default, the intermediate lines discussed above make each pass in a horizontal direction. If mostof the polygons are extended in the horizontal direction or if using theHangingwall/footwall/interburden coding option, the user can force the intermediate lines tocross in the other direction by toggling ON the Use vertical slices checkbox.

o Group by drop-down box

Polygons on a plane are separated into groups to form the boundaries of regions. If two polygonsare situated so that one is inside the other, without lines overlapping, then the area between thetwo grouped polygons will be coded while the area within the inner polygon is not coded. Ifpolygons are not in the same group and one is inside the other, the inner code has priority. Thismeans that there is no need to digitise double boundaries.


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There are 3 different options to group polygons.

Object + Element Name

This option groups polygons by those within the same geometry object and with the same

attributed element name. (Element names can be given using Element Attribute onthe tool bar menu.) (e.g., geometry object ‘pit1’ contains polygons with element names‘blues’ and ‘reds’. All the ‘blues’ on the same plane will be grouped together, and all the‘reds’ on the same plane will be grouped together.)

Element Name

This option groups together any polygons with the same attributed element name, nomatter which object it is in. This option assumes that polygons with the same elementname also have the same model code. (e.g., geometry objects ‘pit1’ and ‘pit2’ are selectedfor coding. Grouping by ‘Element Name’ is selected; therefore all elements named ‘blues’,within either object, are grouped together for coding, and all elements named ‘reds’,

within either object, are grouped together for coding). Model Code

This option groups together all polygons with the same model code. (e.g., polygons named‘blues’ and ‘reds’ are selected for coding from geometry objects ‘pit1’ and ‘pit2’. Polygonsnamed ‘blues’ and ‘reds’ have a model code of 8. Grouping by ‘Model Code’ and codingresults with all polygons coding the model together).

o Compute partials one polygon group at a time

When this option is toggled ON, coding is performed for each group of polygons separately. If thegroups overlap then partials in an individual block may sum to a value greater than 100%.

Polygons with the same element attribute Polygons with the different element attribute


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The Code button, located on the lower right-hand corner of the Code Model tab, is used to actually code themodel. After all the desired settings have been selected on the Code Model tab, pressing the Code button willapply those coding options to the model. The Code button is activated when the corresponding geometry has beenselected. (e.g. when coding ‘From Polygons’, the geometry set selected on the ‘Geometry’ tab must contain at leastone polygon, and when ‘Coding From Solids’, the geometry set must contain at least one solid.)

Note: Model coding writes information to the msAudit.txt file, such as what item is being coded, the name of the

geometry object used, if the reset option is used and the rows, columns, and levels included.

Block Model Coding Methods

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