UV unwrap distortion


#1

Hi,

Why does the UV editor distort shapes flat when it unwraps them? it makes matching them to already existing textures more difficult. Ideally I would want to to output the same way I get from an unroll surface.


(Brian James) #2

Hi Owen,

Unwrap will work on doubly curved surfaces and polysurfaces but UnrollSrf is limited to developable geometry. This may be why you aren’t getting a default alignment that you like. If you have an example showing what Unwrap gives you and can explain what you’d like instead, I can file a feature request. I know we already have several open items looking for better default alignment of the UVs in reference to the texture used but more examples are always welcome.


#3

Here’s an example. I would think that I would be able to get the same effect with the uv unwrap that I would with an unroll where I picked the same edges.
Unwrap-Distort.3dm (111.4 KB)


(Brian James) #4

Are you asking for this…

Instead of this?


#5

No the issue is less the layout that’s easy enough to change. The issue is that the shapes are distorted making it difficult to an existing texture to the model.


(Brian James) #6

I’m able to rotate the UV mesh to match the UnrollSrf result exactly. However the size of the UV editor you drag out will make a difference on how much you would need to scale the UVs as well. I don’t see a distortion though. Am I missing something?


#7

I guess I’m looking for a way to simplify the work flow to avoid all the scaling and rotating to get the uv mesh to line up. Ideally there would be a way to unrwap it so that it maintained the size the way an unroll does. Maybe a constrain when you drag out the uv editor?


#8

Hi Brian, i guess what Owen is asking for does partially happen already for planar rectangular surfaces after beeing unwrapped. The UV direction of the surface (if it is planar in 3D) should be maintained so the unwrapped result is aligned to the world axes in texture space.

What i personally would like to see further enhanced is that texture space is not wasted as shown in both of your images. There is some nesting required which will scale the organic shapes so they cover more space of the texture. The linear (largest) piece is the limit of scaling so the proportion between the 3 meshes is kept. I guess all 3 parts should be twice the size.

c.


#9

I’ve been unwrapping rectilinear shapes and that works pretty much as expected. It would be nice if there was a way to maintain the aspect ratio but it’s easy enough to scale.

I’ve been unrolling the shape, creating a bounding box on the unrolled shape, and then using that as the template for the uv editor and that gets me pretty close. It also has the added benefit of creating a flattened set of surfaces that can be exported for texturing.


(Brian James) #10

Thanks for the feedback Owen and Clement. There are open bugs being worked on to improve the UV editor and Unwrap in v6. I’ll add this test case and thread to that information.