Shape Keys and Poly Reduction?

Hi all, we have a fairly high resolution mesh, with lots of blend shapes governing various aspects.

What we’d like to do now, is to create additional LOD meshes for this object. And we’d like the various blend shapes to stay mostly intact.

I’d think this could work fairly easily, by just keeping the transform values for all vertices that remain after decimation. But does it work that way?

Are here any creative solutions we could use to make this work? Any specific means or method of reducing the polycount, that will keep the blendshapes sort-of intact?

we don’t have an exact figure yet, but we’re likely to have in the region of >50 blendshapes, maybe close to 100. Redoing them all on a lower detail mesh is generally not an option.

I assume you are talking about Blender Shape Keys. May be the safest and quickest way is to reduce vertex count by removing closely spaced edge loops. Shape Keys will function after you do that.

This sounds interesting, but how? i’d normally do these with remove doubles, or dissolve edge, i feeel like those methods will mess with the shape keys though. And in any case they’re very slow. Outright deleting the edge loops would leave holes in the mesh

is there a way to accomplish it en masse with some kind of modifier or script

Blender has a delete edge loop option in the delete menu.

the other option is to experiment with scripts pair the decimated verticies with original verticies based on proximity, and then use that to copy the shapekeys over, something like the following pseudocode:

for each decimated vert:
         pair with nearest vert in source

for each shapekey
       create empty key in decimated mesh
       for each decimated vert
               move location in key to location of paired vert in the original mesh

deleting edge loops doesnt seem to work :confused: screws up the vertex orders i guess, everything explodes

this sounds like the most optimal solution, but also a nightmare of time and coding, in a language i’m not familiar with.

has anyone else ever done it before and made such a thing as a commercial product?