how do I delete edges whilst keeping UV mapping?

AlexLegg · May 2010

I making a complicated, twisting, turning length of rope, that joins back onto itself.

I've have a 6 sided cylinder, mapped with a tiling rope texture. This then follows a spline path to make the complicated shape.

I now want to start deleting edge loops on the mesh to reduce the poly count.

I've added an edit poly modifier and removed edge loops, but the mapping starts to slip. The straights look okay, but on the curved sections it looks really bad and you can see that the texture doesn't align.

I've tried copying the UVW modifier, and re-applying a UVW map, but they don't work. I can't bake the texture from the original as I want to keep the map as a tiling one.

Can anyone suggest a solution?

Cap Hotkill · May 2010

what 3D app are you using?

In Modo i just tab Backspace to delete edges while keeping the faces and the UVmaps, Maybe just go to your Edge section and click on Delete Edges, maybe it works the same way in other apps.

Ged · May 2010

if your in max then you need to collapse all in the modifier stack but you still run the risk of messing something up so you will have to add a uvw modifier after the edge editing to see wether its all worked out the way you planned

Eric Chadwick · May 2010

With a tiling UV, it's better to re-map the thing after optimizing it. Removing edges on a tiling UV is often problematic. Just take a look at the UVs before and after. Sounds like you're using Max, so spline UV would be the way to go for this.

Mark Dygert · May 2010

Like Eric said, I think you should at least re-uv map it. If you don't, you'll have a bunch of seams and bunch of pieces that are stacked on top of each other. This could cause smoothing issues (see right, stacked) when you export to a game engine, depends on the engine though.

If you lay them out in a straight line (see left, tiled) so that only one piece fits the 0-1 space and the rest extend above or below then you'll only have 1 seam. If you stack it could create a smoothing issue on every UV seam (see right).

Depending on how many pieces are there, I would probably select a top edge, click loop and stitch, doing that all the way up or down until all the tiles are joined to one giant tiling piece. That way the shape and size of each tiles doesn't change, which you risk doing if you remap it.

AlexLegg · May 2010

Thanks so much for all the help.

I am using 3ds Max 2010.

I had never heard of spline UV's before, so did a little reading and had a go. It got a pretty good result, but needed a bit of cleaning up still. Some of the textures were still miss aligned.

Vig, thanks for taking the time to illustrate yout process. The rope is very long with many sections, so I think it would take me a long time to stitch the UVs and I would have a very very long image in the UV window! So I haven't attempted this method yet, but I think it would work well on a shorter section.

I think I have the solution now though, which seems so simple, I feel stupid that I didn't try it earlier....

Instead of making a 6 sided mesh follow the spline path, I just made the spline 6 sided and renderable! I can then control the curves via the interpolation. I have very little clean up this way too.

So far it all seems OK.

how do I delete edges whilst keeping UV mapping?

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