how to preserve uv when making lod?

I made a high detail model for a game and now i need to make an lod. but when i manually delete polys and stuff, while still keeping the overall shape of the item, the uv screws up and gets all jumbled up. its probably because i get rid of some of the edges that have the uv seams on them.

i tried the dissolve feature, but that seems to only work for faces, and i need to get rid of vertices and edges too.

here are some pics of what i want:

http://puu.sh/1Ly7V

i want these two connected cubes to become one cube, while still keeping the seams and having the square-ish shape of the uv. is there anyway to do this?

Try the decimate modifier in “unsubdivide” mode. Aside from that there’s really no way. UVs store vertex order and location. Changing either destroys how the rest are sorted. In the future your workflow should go as follows:

  1. Model low poly

  2. UV unwrap

  3. Subdivide/multires

  4. Sculpt

This way you keep a lowpoly version that you can work with later. Alternatively you could create a lowpoly object afterwards, UV unwrap it, and bake color/normal/etc. data from selected to active using the high poly to the low poly.

thanks for the advice. i can always re-arrange the uvs myself. i’ll make sure to do your suggested workflow from now on.

Just an FYI : the Decimate modifier has recently been worked on and in recent releases preserves UVs during the decimation process. It works pretty well.