UV problems in blendShape script

[mloomis]

Greetings.

I've written a MEL script to import a series of OBJ files and combine them in MAYA using a blendShape deformer. I've been partially successful in achieving what I want, but I still need a little advice.

Each imported OBJ file represents the deforming geometry of a finite element simulation as it exists at a certain point in time. The topologies of the geometry in each file are all the same (same # of vertices, same connectivity) and UV texture data is already present at each vertex. In this case, the UV data is intended to map into a ramp texture (on the MAYA side) in order to display a color-coded visual representation of some engineering variable (such as stress or pressure) over the surface of the object. This UV data is changing with each new time step, so the resulting colors at each time step should change also.

The crux of my problem seems to be that the blendShape only recognizes the first file's UV information and uses that static data throught out the blend instead of interpolating it from target object to target object. In other words, after performing the blendShape operation, the resulting geometry is deforming OK, but the texture shading is not changing as it should. I've verified that the UV data is correct for each of the separate target shapes -- each of them displays color correctly in MAYA. Is there a flag that will force the blendShape to recognize the changing UV information? If not, is there a workaround that you might suggest?

Thanks in advance for any help or suggestions.

Michael Loomis, animator
Maya and Composer User and Abuser

[serpent]

Yep, man, that's it - blendShape affects only CVs' coordinates.

The one way to make texture "blend" with geometry is to create set of textures. All of them You'd map on base object. So when You create those other textures, You should take in account new locations of each CVs.. e.g. if You make face of lad blending to face of man and then to face of old man, then make man's face as base object and create at least 2 maps - smooth and wrinkled ones, both painted on man's face to achieve minimal deformation of texture.

Another way is base object's UVs animation, but if You have complicated geometry, then good luck..
And.. to beter understand way Your geometry deforms, try to paint ( RMB on obj and Paint->objShape->rgb ) some marks at significant places of geometry in different blend shape states, then export maps and compare them.
At least You could try to combine both methods.
I hope that it will help.. Happy Y2K and goodluck.