Getting a overlapping uv error

[EliteSniper177]

I'm working on an unreal game for my game design course, and I can't seem to get this tree asset imported properly. Before I didn't have a lightmap cannel set up, and was getting a no light map error. So I added another UVW unwrap, set it to channel 2, and made everything nice and flat, no overlapping or inverted faces. Now everything seems to be working fine up untill I render lighting, then I get an overlapping UV error. The UV map is showing on both channels, i used the same map for both so I know there are no overlapping points on the first channel either. I'm at a total loss for what to do, I don't have a whole lot of experience with UDK or 3DS Max 2012. Any help is greatly appreciated.

Not sure if this is a related issue, but before when I tried to add a lighting channel through UDK, I was getting a cannot convert to DX3DMesh error.

[darthviper107]

The DX3D error is common and doesn't really mean anything but it can stop you from generating it within UDK, just means you have to do it in 3ds Max.


When you render lighting does it look correct? I've got stuff that gets the overlapping UV error that doesn't have overlapping UV's, but things render just fine. Plus sometimes I've had it where increasing the lightmap resolution will make that error appear, although again it still works fine.

[Tearl]

did you unwrap the entire mesh in Max, or just selected faces or by material ID or something like that?

[taz1004]

From my experience, when it says I have overlapping uv, I did have an overlapping uv. And it's usually those things that just appears correct. A cylinder for example looks like all faces are laid out perfectly but the last face was actually stretched and overlapping the rest. If you upload your mesh somewhere, I can take a look at it.

[EliteSniper177]

I'm pretty sure I got the whole thing, here's my UV map, also attaching the model in case anyone spots an error in there.

UV map:
http://www.gamefront.com/files/21506450/TreeUVW.uvw

Model:
http://www.gamefront.com/files/21506...11_Unreal2.max

[Tearl]

I took a look at your model. I want to make a suggestion first. ProBoolean all that stuff together. You'll get a mesh that's half the triangle count and easier to work with.
On the UV's, there were no overlapped faces, but there were inverted faces. You'll want to get that fixed so UDK doesn't get confused and consider those overlapping. Also, when you have those seams in the UV editor (the brighter green seams)...those edges that are right up against each other should be stitched. That'll help avoid any possible precision errors.

Neat tree by the way

[taz1004]

There were overlaps. As I've said in my first post, it's something that could be missed easily. Problem is that your mesh is in quads. And some of your UV shells of those quads are concave shapes. And when those concave shapes gets auto-triangulated, it could draw a line through the corners and create overlap. I fixed these and was able to eliminate the overlapping error message. I hope the images below explains the situation.

One on the left is how I fixed it.


If it gets autotriangulated as the top one, it should be okay but if you get unlucky and gets trianglated as the bottom one, it will create overlap.

[haldolium]

could it be, that Unreal too doesn't like that much stretched polys in the UV too? Mudbox for example wouldnt accept that kind of unwrap since the polys (in the unwrap) are too much stretched and their seams are too near to each other.

In any case I'd avoid both such unwraps and that what Tearl said too for modeling.

When doing unwrap for sphere objects you basically have two choices: /i meant default, sorry. with the seams on the pole (can be usefull, can be nasty - depending on what you want to do with the object) and planar + relax for each half-sphere. Maybe you can try that one.

/oh well nevermind (one maybe shouldt break posting for an hour and then just hit "sent post" ^^)


Anyways: the source of the concave poly problem in the UV is the same here.

[Tearl]

On the UV's, Taz is spot on...I totally overlooked that. His fix will have you right as rain without any more modeling...though I'd still optimize the model

[taz1004]

I did find unmerged edges too so merging all the UV edges as Tearl said is always good idea. I found 4 spheres and the tree trunk that had those concave quads FYI. And as others have said, unless you have other reasons, I would either cut the spheres in half (along the equator) and project UV from top and bottom. Or use cylindrical unwrapping. Will yield much cleaner UV layout.

[EliteSniper177]

Yes, that did it Taz, I didn't realize that would be counted as an overlap. I will definitely try and redo the model with ProBoolean like Tearl suggested, but for now I'm just glad it works! Thanks everyone!

[darthwilson]

Let this button be your guide



P.S you have to have faces mode selected to press this button.

[haldolium]

max recognizes concave polys as inverted and only real overlapping (as in one above another) as overlapping, while UDK doesn't distinguish these two.