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

2. 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 doesnt represent details

3. Sketches

4. 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)

5. 3D Sketches (Sesame) Sketches on paper and their corresponding 3D sketches in Sesame

6. 3D Sketches (SketchUp) A car in SketchUp A model of airplane created in SketchUp and exported to 3D renderer

7. 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.

8. Some of 3D Sketching Operations Extrusion (Translational Sweep) Rotational Sweep CSG Surface Dragging

9. 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

10. 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 doesnt have any features similar to the Moving technique of Sesame. Instead of moving over to the next surface, the object would collide

11. 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

12. 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 its possible to tweak the number of polygons Too many polygons will affect the performance So, using conventional CAD for tweaking could be an option

13. 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).

14. 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 Doesnt 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 doesnt provide all necessary 3D Sketching tools: No support for freeform extrusions or rotational sweeps (the concept of stretching isnt the same as sweep)

15. 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 doesnt allow to export non-rectangular surfaces

16. Other Offline Sandboxes At the moment Second Life doesnt 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) WindyWeather Vanalten's Max Script Vyrnox Ming's Chisel

17. 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

18. 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

19. 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 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/ Simple SketchUp to Second Life Exporterhttp://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/http://eightbar.co.uk/2006/09/29/google- sketchup-second-life-export/ About Offline Sandboxes - http://secondlife.com/knowledgebase/article.php?id=407http://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%29http://en.wikipedia.org/wiki/Sketch_%28drawing%29 CSG - http://en.wikipedia.org/wiki/Constructive_solid_geometryhttp://en.wikipedia.org/wiki/Constructive_solid_geometry Sweep Methods - http://www.ipf.tuwien.ac.at/fr/buildings/diss/node36.html

20. Thank You… Questions?