Advice on Optimal UV Mapping

cadgonegames

Hi there,

I've been looking around for some advice on the most practical UV layouts, in terms of minimal distortion Vs. Maximum UV space.

Now I have no issues with unwrapping practically any shape, and packing them all up nicely, but I tend to struggle when it comes to unwrapping 'bulge' cylinders, given that yeah, I can unwrap it via 1 seam, but it distorts really ugly to paint, or if I unwrap it into a nice box, it distorts like crazy!

I try to normalize everything I unwrap, but again with cylinders, I try to unwrap the sides into 1 straight line, and have the tops and bottoms separate, but when pack normalizing these, the UV space layout is kinda meh!

I've attached a few different various examples of methods I'd tend to use on a base shape, just looking for advice on how the majority would go about it!

Would be cool to have a thread based on the most practical way of unwrapping certain common shapes

Thanks in advance!

Eric Chadwick

This has been talked about before. So I did a search for "cylinder unwrap".
http://www.polycount.com/forum/showthread.php?t=134749

cadgonegames

Yeah I saw that post, didn't really give me an answer to what I was looking for unless you are referring to manually adjusting each row of the verts to reduce the ammount of distortion?

Bartalon

I think it really depends on a lot of factors. Which software are you using, what material is the table made out of, how important is the asset, etc.

If you're stuck with Photoshop then it might be easier to texture the sides of the tabletop/base with perfectly straight islands, but if you're using a 3D painting program, that problem disappears.

If it's a brushed metal or something it might be problematic to have a seam right in the middle of the metal compared to say, wood or something that's noisier and easier to hide seam between grain/planks.

I often deal with shapes similar to yours by beveling edges where I can get away with connecting what would otherwise be two UV islands. It increases the triangle count but the vertex count doesn't fluctuate much (assuming your smoothing, UVs and material splits are set up properly). Sometimes beveling some edges and sewing UVs can actually make the count go down, but if you are doing an art test or something and given a really constrained triangle count, you may not be able to afford beveling.

Left: 592 tris, 396 verts, poor UV scale (splitting the long bits would result in more islands to texture)

Right: 664 tris, 394 verts, fewer islands but some parts might be more difficult to texture in 2D application due to orientation



Also practically speaking, the viewer would probably rarely see the underside of the table so I would stack those UVs over the island for the top of the table.

cadgonegames

Thanks for your reply!

Yeah I'm using 3ds max to unwrap my objects, taking them across into Photoshop for texturing. I was always using a smoothing group change == UV unwrap seam workflow for unwrapping, so given the table top for example has a plastic finish, which a secondary material on the sides, I tend to break them apart from each other.

I know I could unwrap the top + the sides in 1 island, but then I'd be crossing over smoothing groups on a single island.

In terms of your budged section, did you do that manually by adjusting each row as it increments then I think?

Thanks again.

Bartalon

In terms of your budged section, did you do that manually by adjusting each row as it increments then I think?

Are you talking about the middle area where the UVs pinch in? If so, I just used the unfolding tool in Maya, nothing special. The only manual alignment I did was at the top and bottom (I took a screen cap at the wrong time so the bottom is still crooked).

TomDelboo

I would use a 2 by 1 ratio.
This will end up in less wasted uv space in this case.

cadgonegames

Thanks for the help guys, I forgot about using non-square maps.