I have a model with UV and a texture. And then I made some changes on the UV (but not the topology). How could I re-bake the texture according to the new UV, so it looks the same as before?

If you have the mesh with both uv sets, the uvdistance() VEX function can be used in a Composite VOP generator to map from one set of coordinates to the other. It's not easy to set up, but will offer the highest possible quality. The bake texture rop that uses mantra is another option but will diffuse the textures a little bit and has trouble anywhere the mesh intersects itself.

jsmack
If you have the mesh with both uv sets, the uvdistance() VEX function can be used in a Composite VOP generator to map from one set of coordinates to the other. It's not easy to set up, but will offer the highest possible quality. The bake texture rop that uses mantra is another option but will diffuse the textures a little bit and has trouble anywhere the mesh intersects itself.

Could you elaborate it a bit? It sounds a bit beyond my current Houdini knowledge.

I have both uv sets stored as two attributes (uv and new_uv). But I can't find uvdistance(). The closest thing I found was uvdist() [www.sidefx.com].

And I never used Composite VOP before. Its document [www.sidefx.com] is... a bit lacking...

The labs baker should do this for you, otherwise if you want to roll your own, I have some examples here:

https://tokeru.com/cgwiki/HoudiniCops.html#sample_3d_geometry_in_cops [tokeru.com]