Towards 3D Conceptual Design in Second Life Loutfouz Zaman COSC6002R Winter 2007.

Towards 3D Conceptual Design in Second Life

Loutfouz Zaman

COSC6002R Winter 2007

Sketching?

What is a Sketch? Conceptual design Basic design element that defines approximate size and shape of

features of a model It entails using lines, circles, arcs, rectangles, etc.

What is good about it? Usually serves quickly to record ideas for later use Sharpens an artist's ability to focus Inexpensive and time efficient A prescribed part of artistic development for students and professionals

alike What is bad about it?

Usually doesn’t represent details

Sketches

3D Sketching

Traditionally sketching was performed on paper. Today, design practices such as architecture are becoming

exclusively digital and collaborative in terms of the exchange of ideas over digital networks.

Conventional CAD system such as AutoCAD are unable to providing the flexibility of sketching due to the strong attention to details

This pushed the demand to support sketching in computer-based system

Examples: Google SketchUp (commercial) SESAME (academic)

3D Sketches (Sesame) Sketches on paper and their corresponding 3D sketches in

Sesame

3D Sketches (SketchUp)

A car in SketchUp

A model of airplane created in SketchUp and exported to 3D renderer

About 3D Sketching

What 3D Sketching entails?Same as 2D Sketching (using lines, circles,

arcs, rectangles, etc. In addition, it involves 3D operations such as

Translation Sweeps (Extrusion), Rotational Sweeps, Edge Dragging, Surface Editing, Constructive solid geometry, Cloning, etc…

These operations extend 2D Sketches into 3D.

Some of 3D Sketching Operations

Extrusion (Translational Sweep)Rotational Sweep

CSG

Surface Dragging

3D Sketching vs. Conventional CAD A study at York U was

conducted to evaluate the effectiveness of Sesame (3D Sketching system) vs. 3D Studio Max (Conventional CAD)

Design Quality was measured Results from SESAME

sessions were rated significantly higher in terms of creativity and overall quality.

Ratings were performed by a leader of a design studio and has many years of experience in urban design.SESAME 3D Studio Max

Moving objects in 3D with SESAME

The moving technique utilizes the fact that people easily recognize the depth-order of shapes based on occlusions

The technique utilizes the fact that people easily recognize the depth-order of shapes based on occlusions

In contrast to conventional techniques, the movement surface and the relative object position is determined using the whole area of overlap of the moving object with the static scene.

The resulting object movement is visually smooth and predictable, while avoiding undesirable collisions.

Second Life doesn’t have any features similar to the Moving technique of Sesame. Instead of moving over to the next surface, the object would collide

Why Second Life would benefit from 3D Sketching tools? In virtual worlds such as Second Life and in gaming environments in

general the attention to detail is usually not important, unlike in fields such as engineering where conventional CAD software is utilized

Normally, attention to detail is actually discouraged in gaming environments due to performance issues

3D Modeling process in Second Life becomes faster and easier Rotationally can attract more new residents Impoved Moving, Manipulation and Grouping Interaction techniques

that 3D Sketching system such as SESAME provides will also simplify and accelerate 3D modeling

Potential problems of using 3D Sketching in Second Life If not implemented efficiently it may generate

models with more polygons than if using conventional 3D modeling where it’s possible to tweak the number of polygons

Too many polygons will affect the performance So, using conventional CAD for tweaking could

be an option

Building in Second Life

All building in Second Life is based on “prims”

"prims" are the basic building blocks used to create all objects in Second Life

More complex objects are created by applying various sculpting operations on “prims”

Some of these operations resemble 3D Sketching such as Stretching which is Edge Dragging in Sesame (Rescaling Prims).

Limitations of Building in Second Life Not very user friendly interface

Too many menus, parameters, bullets, textboxes, etc Requires extensive training, if the user wants to build something more interesting

than just boxes and cylinders Potentially scares away newly registered users who are unable to build models

without extensive training Does not employ 3D Sketching effectively

Doesn’t have 2D sketching tools unlike SESAME and SketchUp (lines, arcs, circles, rectangles…etc)

As a result, you are forced to use only the provided prims – you cannot create your own from scratch.

To come up with the prim you want, you need to engage in extensive sculpting which is time-consuming

It doesn’t provide all necessary 3D Sketching tools: No support for freeform extrusions or rotational sweeps (the concept of stretching

isn’t the same as sweep)

“Offline Sandbox” to import SketchUp Currently, it is possible to export from Google SketchUp to Second

Life using a plug-in The plug-in writes basic model information to a text file, from which it

can be imported to Second Life in notecard form When loaded, an in-world object parses the notecard and re-

generates the model in Second Life There are limitations:

only works for fairly basic objects doesn’t allow to export non-rectangular surfaces

Other “Offline Sandboxes”

At the moment Second Life doesn’t support object importing in any of the common formats

Some residents came up with their own methods of importing objects: Jeffrey Gomez's Offline Builder WindyWeather Vanalten's Max Script (Script to

support MAX) Vyrnox Ming's Chisel

What can be done?

More effort can be put to develop a working plug-in that could export SketchUp models

A better solution is to implement 3D Sketching capabilities inside Second Life to complement the existing 3D building tool

In this case 3D Sketching capabilities will facilitate modeling

process Benefits that they provide will attract more new

residents

Collaborative Creation in Second Life Currently, it is possible to construct the

same object(s) with several other Residents (at different times, or simultaneously) in Second Life.

We have conducted an experiment with collaborative 3D sketching design in a co-located environment

The participants were asked to design and manipulate objects in 3D environment using laser pointers

SESAME was modified to support collaboration

The results indicated that the users generally liked the ability to perform 3D sketching collaboratively

More studies need to be done to find out how collaborate 3D sketching affects creativity

The experiment is extendable to evaluate collaborative 3D sketching in remote environments such as Second Life

References J.-Y. Oh, W. Stuerzlinger, J. Danahy, Comparing SESAME and Sketching for

Conceptual 3D Design, Sketch Based Interfaces and Modeling J.-Y. Oh, W. Stuerzlinger, J. Danahy, SESAME: Towards Better 3D Conceptual

Design Systems W. Stuerzlinger, L. Zaman, A. Pavlovych, J.-Y. Oh, The Design and Realization of

CoViD, A System for Collaborative Virtual 3D Design, Virtual Reality J.-Y. Oh, W. Stuerzlinger, D. Dadgari, Group Selection Techniques for Efficient 3D

Modeling J.-Y. Oh, W. Stuerzlinger, Moving Objects with 2D Input Devices in CAD Systems

and Desktop Virtual Environments From SketchUp to Second Life -

http://games.slashdot.org/article.pl?sid=06/10/02/2244220 Simple SketchUp to Second Life Exporter -

http://www.3pointd.com/20060929/simple-sketchup-to-second-life-exporter/ Google Sketchup -> Second Life export - http://eightbar.co.uk/2006/09/29/google-

sketchup-second-life-export/ About “Offline Sandboxes” - http://secondlife.com/knowledgebase/article.php?id=407 Collaborative Creation in Second Life - http://secondlife.com/whatis/building.php SketchUp Wiki - http://en.wikipedia.org/wiki/SketchUp A Sketch - http://en.wikipedia.org/wiki/Sketch_%28drawing%29 CSG - http://en.wikipedia.org/wiki/Constructive_solid_geometry Sweep Methods - http://www.ipf.tuwien.ac.at/fr/buildings/diss/node36.html

Thank You… Questions?