Full UV Unwrap with Mirror Modifier
One of the biggest problems I encounter when trying to implement a non-destructive workflow in my 3D models is when it comes to unwrapping UV.
It would be ideal if modifiers such as Mirror allowed to unwrap the entire mesh without having to apply the changes of the modifier.
I suppose it can be difficult to manage the symmetry within the UV map, so I understand that the geometry automatically generated would not be editable, but automatically refreshed by editing the coordinates of the real geometry.
Once unwrapped, it would also benefit other aspects, such as Texture Painting, allowing differences to be drawn on both sides of the mesh.
8 Comments
This feature is badly needed. And implementing enough to be functional would not be difficult. Even an option that forces the mirror line to be a straight edge, and the mirrored UVs to be directly stitched to the original side would be miles better than nothing. The current features do not allow a non-destructive workflow if you want both sides of your model to have unique UVs, and both sides stitched together. We are forced to apply the mirror modifier, making future changes to the model much more difficult. Anyway, my point is that this is a necessary feature.
I have another thought for this feature: the UV unwrap operator already has a parameter for 'use subdivision surface' (as long as the SS is the first modifier). Maybe it could be expanded to include a 'use mirror modifier' parameter. Then it would still need a modification to mirror islands by their bounding box center instead of just at v = 0.5.
In Your 'great' example part of islands are flipped in one way and other half are mirrored in other. I see inconsistency in expected behavior.
Flipping per island It could be theoretically be done by finding bounding box of uv island and mirror it with that pivot per island.
Do you know any other dcc that do have this behavior?
BTW what other aspects? How would Texture paint benefit from different uv wrapping mirror modifier?
UV modifier has a symmetry feature. It can mirror UVs by U or V.
* @Josephbburg * Which "UV modifier" do you mean?
* @Alvaro Luque * Oops I meant mirror modifier! Sorry. Array modifier also has ability to array UVs.
* @Josephbburg * by default, the Mirror modifier generates overlapped islands on top of the real geometry map. This is not really convinient if you want to do any sort of normal baking for example, and does not allow you to have unsymmetrized textures on both sides of the model.
As a second option, the modifier allows you to Flip the generated texture coordinates, either U, V or both. This automatically creates maps for every real geometry island, and place it in the correspondent UV map, related to the opposed half quadrant in which the island is placed, with the relative offset that you configure. All edges that clip the mirror border will be considered as seams , and unwrapping won't do the calculation considering the geometry as a whole. It wont consider the generated island while packing the texture coordinates.
Let me try to illustrate it with an screenshot:
{attachment Mirror_2png}
* @Alvaro Luque * That's really helpful, I see what you mean, now. Good idea.