On Nov 13, 2008, at 1:00 AM, Bright wrote:
CSG modeling widely using on cad/cam ,btw google sketchup seems to support this way .away3d have some primitive model ,Some way can do csg calculate(boolean) and get complex model ,pls give some advice,thks
CSG used to be widely used. It's now only really used in CAD/CAM applications that use implicit surface modeling and bounding volumes. CSG is not very good for polygon set operations - because CSG trees usually use mathematical representations of surfaces. If you wanted to do NURBS, or higher order surface set operations, then CSG would be the way to go.
There's nothing out there in the public for 3d polygon set operations (in Flash). Tim of PV3D did do some operations in his FloorPlanner application. FloorPlanner uses a home grown BSP algorithm for the operations.
For general 3d polygon clipping, implement a BSP tree algorithm and do polygon clipping within the resulting BSP tree(s). There's a lot of information online on merging BSP trees to peform union/ subtraction/intersection. XOR/AND and the other operations are quite a bit trickier.
SketchUp uses BSP trees, as do most 3d applications. Good luck, Jon
