Max 9: Distorted UVW's on mirrored objects...

Geezus

I've had this problem off and on. Sometimes, in my workflow, it's necessary for me to unwrap an object on a mesh, collapse the stack, detach it and it's mirrored counterpart, apply the unwrap modifier on the unwrapped object, copy that modifier onto the mirrored object, and re-attach both objects to the main mesh. Occasionally, when I do this, I have issues with the mirrored object having a distorted map, despite it sharing the exact same UVW space as it's correctly displayed counterpart. These distorted UV's also display oddly when selected in the Edit UVW window. You can see how the angled lines appear on the faces below, when I select the faces of the distorted object:


Has anyone run into this issue before? I'm sure it has to do with some sort of flipped normal problem with the mirrored object. For this particular issue, it's not a big deal, since I can just blow half the mesh away, unwrap, collapse, symetry, apply unwrap, and edit from there. But, for future issues, with meshes that are not fully symmetrical, but share some identical objects, I'd like to know what's going on here, or what to avoid. Anyone? :]

tremulant

hey geebus,

I think the problem here, is just that 3ds max has some really buggy unwrapping tools. I have had all sorts of problems with them every since I touched the program.

I think your best bet is to just keep the object as one piece. For instance, instead of separating two identicle hand pieces from the object, only sep one, then delete the other., After you modify it, then just mirror and instance over and make them both unique before attaching back to the whole. Also It helps sometimes, instead of detatching from the whole, just to make the hand or something an element, that way you have more control over it inidividually.

Also if you are ever having weird mesh problems...Go into tools, and hit the ResetXform Button. This usually fixes things right up.Then just collapse back and mirror the fixed half.
Hope i helped in some way..

LAter broseff
Dave

MoP

Why don't you just mirror the object itself instead of copying an Unwrap UVW modifier? It really sounds like an odd way to work, especially since copying Unwrap UVW modifiers requires that the geometry (number of verts, vert id etc.) has to be identical.

Personally if I was doing something like this, I'd just model and unwrap a single piece, with a Symmetry modifier sitting at the top of the stack.

Geezus

Thanks dave and MoP. For this piece, I'm able to just unwrap and add the symmetry later, since it's a symmetrical piece. But, I also run into this issue when only certain objects on the mesh are mirrored or duplicated.

MoP, whenever I do run into this problem, the number of verts and geometry is exact, whether it's mirrored or just copied and attached. A lot of this has to do with not fully realizing how I'm going to approach the unwrap until I'm finished the modeling. I'm getting better with thinking about my unwrap during the modeling phase, though.

Honestly, it's hit or miss with this issue. Sometimes it gives me this problem, sometimes it doesn't. When it works, it's very helpful. When it screws up, it confuses the hell out of me. In the above image, both objects share the exact same geometry, and when you have to both on one single unwrap, they share the exact UVW space. Only the mirrored one is distorted...even though it appears to be unwrapped exactly like it's parent. If I take the mirrored object's UVW's and blow them away, and simply snap each vert on it's counterpart on the original unwrap, it displays fine.

Does anyone at least know what the angled lines indicate? I had to end up rebooting the PC to get the lines to go away, since they would appear on every unwrap. Even a simple box, converted to editable poly would have the angled lines in the Edit UVW view. Resetting defaults/restarting max wouldn't fix the issue.

MoP

Er, the angled lines are always there when you make a face selection in the UVW window - it's not a bug.
You can change the "shading style" of the face selection in the Advanced Options window, it looks like yours is set to "hatched diagonal" - you can change it to any number of things from cross-hatched, to grid, to single horizontal/vertical lines etc.

Also, when you say that the mirrored object "appears to be unwrapped exactly like it's parent", do you mean that if you paste the modifier on top of the object, then go into Edit in the modifier, it looks fine?
I'd imagine it would, since it's a copy of the modifier ... however, does it still look fine if you "Collapse To", then add a new Unwrap UVW on top of the mirrored object, and Edit that? I'm guessing it will look messed up...

tremulant

Gawd this post confuses the hell outta me. lol...I think another problem is coming from Chugnutts....I noticed it causes max to act a bit more wonky...since it was made for max 5 originally....Autodesk really needs to step up to the plate and modify some of their uvw mapping tools.

StJoris

I have the same issue a lot when I use copy, and paste on mirrored uv chunks, as you say, they take up the same uv space, just one of them is distorted. I think it might have to do with the mirroring, if I do copy/paste with similar modules that are not mirrored, it works fine. What I do is just map a part, delete it's mirrored counterpart and copy the mapped piece and mirror it.

MoP

Yeah, like I said, I don't think that copying UVWs across to mirrored objects is the best workflow. Personally I don't see why you can't just instance mirror it and use "Collapse To" on the original object once you've finished UVW mapping - don't use Collapse All because that de-instances the objects, just Collapse To will merge both instances. When you're working with identical mirrored objects there is no reason not to use instancing, it only saves time.