Unfolding Geometry

Raymond Arnold

I wasn't sure what type of keyword to use to try and look up the answer to this.

In Maya, and presumably most other programs with UVs, there's an option in the UV menu called "Unfold", in which the program attempts to match the relationshop of the UVs to the relationship between the corrosponding geometry. I'm wondering, is there something that's similar but... sort of the opposite? A tool that unfolds geometry to attempt to match UVs.

I'm working on a project where it's a lot easier to alter the UVs than the geometry. I'm reusing the same texture for a lot of different objects. With some frequency I find myself with geometry that's slightly off, stretching the UVs, but I can't change the UVs even slightly without totally changing how the texture looks.

cycloverid

You could try transferring (transfer maps) the diffuse texture between the meshes. I've tried this before, and the results are okay I suppose.

Raymond Arnold

I'm not sure which problem that's intended to address. I'm working on the graphics for an iPhone game. For optimization purposes we're trying to keep everything using the same material. I haven't used the transfer maps feature much but I can't think what it would do here.

Raymond Arnold

What I'm hoping for is something that works essentially like the "Average Vertices" tool, but compares the verts to the UVs instead of to each other.

cycloverid

I see what you're saying now Raymond, I read a little too quickly through that. I can't help you exactly with what you're asking, because it's a backwards workflow compared to anything I've used. The transfer maps tool would only work on an object that doesn't share textures, after you've altered the geometry and UV's to your liking.

I can only say that planning works very well to avoid these kinds of headaches. If you know the poly budgets and texture sizes ahead of time, you can tailor the geometry or textures to not have these kinds of bad stretching issues later on. I suppose it's too late to make the necessary modifications to the textures now to accommodate for the different ways these textures will be used?

Good luck!

Raymond Arnold

It's not that I have a bunch of geometry with stretches all over it. I'm in the process of creating a variety of desert canyon environment assets, each of which uses the same rocky/sandy texture, which I'm also still in the process of adjusting. But the general shape of the texture (basically a gradient between sand, rock, and a different kind of rock) pretty much needs to stay the way it is.

My current workflow generally goes:

1. Create a base mesh that fits the canyon gradient texture.
2. Do the UVs for that base mesh
3. Duplicate the mesh a few times to create variants of the idea. (For example, start with a wall of rock, and then create several similar walls that bend in different directions so that I have a flat wall, and L-shaped wall, a curved wall, etc).

It's while I'm tweaking the duplicates that I usually end of with stretched UVs. Some degree of stretching is inevitable and that's fine, I just want to keep it subtle enough that the player won't notice. A lot of time I need to radically bend a section (such as creating an L-wall section out of a flat section), and then I have go in manually to tweak each vert so that it's close to matching the original UVs. Average vertices actually does a pretty good job of helping, but it also shrinks the verts towards each other.

I don't desperately need the tool I'm hoping for, it would just make some parts go faster.