how do i retrieve vertex informations of a prim made by BRepPrimAPIs?

cloudage
Wed, 01/07/2009 - 19:41

Forums:

i just finished reading the tutorial pdf,and i got how to build prims and how to do boolean operations,now my problem is obtain the vertex buffer and index buffer of these prims or boolean operation results,i need these data to create meshes in another graphic engine.

any help please?

Roman Lygin
Wed, 01/07/2009 - 23:14

Can you be more specific of what you are doing and expecting to achieve ? A step-by-step description of your process should be helpful.

Thanks.
Roman

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cloudage
Thu, 01/08/2009 - 12:44

Thanks for reply.
i`m working on these:

1) Build 3d prims(box,sphere,cylinder,etc) at runtime

2) Do boolean operations on these prims

3) Transform prims and boolean operation results into meshs

4) Obtain vertex buffer and index buffer of these mesh

5) Transfer these buffer datas to a external graphic render engine(ogre,irrlicht,unreal,etc)

6) Inside that external graphic render engine,use these buffer datas build a mesh object,and add it into the scenegraph.Then i finally displayed the prims build by CASCAD with my favorite graphic engine.This is my goal.

Patrik Mueller
Thu, 01/08/2009 - 12:59

Hi,

try at the triangulation inside OCCT: BRepMesh_IncrementalMesh and BRep_Tool::Triangulation. If you use windows take a look at the "02_7_TopologyTriangulation" sample. I do similar...

Best regards,

Patrik

cloudage
Thu, 01/08/2009 - 15:29

thanks,but i saw BRep_Tool::Triangulation will return me a Handle_Poly_Triangulation,it seems not a vertex buffer but some thing can be use to gain the real buffer,but i don`t understand how to use it.what should i do with it,please?

Rob Bachrach
Thu, 01/08/2009 - 15:35

You might want to check out the code in:

http://www.opencascade.org/org/forum/thread_14748/

Rob

cloudage
Thu, 01/08/2009 - 15:47

i got it.thank you very much.thanks all of you.