Chris B nous apporta ses lumieres en ce 2008/02/12 07:21:
> "here_I_am" <nomail@nomail> wrote in message 
> news:web.47b1738e5f9a6c867b1612e30@news.povray.org...
>> Hi everybody!
>>
>> I have this face scene,where I have to define different region based on 
>> the
>> location on the face(Such as one region for nose other for lips..and so 
>> on) but
>> the problem I am facing is that even though I know the coordinate for all 
>> the
>> triangle in the scene file i don't know which one corresponds to which 
>> region
>> and I can't do this randomly since scene file has 15000 triangles.
>>
>> I would appreciate if you guys could help me out here.
>> Thanks
>>
> 
> The best approach depends on what you need to do with the different regions.
> 
> I suspect that the most effective approach overall would be to use a 
> modeller (either the one you created the mesh in or another modeller that 
> can read the mesh) and split the object down into separate meshes for each 
> of the 'regions' you need to manipulate independently.
> 
> Failing that, you can use CSG with meshes (so long as the mesh normals are 
> all ok). You may therefore be able to use objects to carve areas out of the 
> face and split it up in that way. For example, you could define a simple 
> squashed sphere and position it (using trial and error) to engulf just the 
> nose. You could then use a sphere with the same values in a CSG intersection 
> with the mesh to isolate the nose and manipulate it independently of the 
> rest of the face.
> 
> If you only need to identify separate regions for texturing it is possible 
> to use CSG within an  'object' pigment, so you could define a texture that 
> corresponds to the regions that you identified by trial and error.
> 
> If you only need to find points on the surface of the face (e.g. for 
> positioning eyelashes, glasses, a pipe or a hat) you could use the 'trace' 
> function. Once again this can be done fairly quickly with a little bit of 
> trial and error. Use 'trace' to locate a point on the surface somewhere near 
> where you want to be. Add a little sphere or a thin cylinder to your test 
> render and refine the trace parameters to home in on the points you need - 
> e.g. the bridge of the nose, the corners of the lips etc.
> 
> Also, if you have development skills you could use your favourite computer 
> language to split the mesh up using mathematical rules that you could devise 
> based on the trial and error technique above.
> 
> If you can give a bit more of an indication of what you need to do it'll 
> probably be possible to recommend a particular approach.
> 
> Regards,
> Chris B. 
> 
> 
If you use CSG to cut a mesh, you don't need the mesh normals to be correct, or 
even the mesh to be closed.
You need a well behaved mesh if you use it to cut another object.

-- 
Alain
-------------------------------------------------
If you are good, you will be assigned all the work. If you are really good, you 
will get out of it.

Post a reply to this message