mirror uvs

[Rudity]

with cylindrical mapping for a face you sorta can.

I cylindrical map the face.
Then take all the uv's on one side of the face, scale them on -x untill it looks the same size as the other side.
Then I move it over top of the other side..
scale and move again untill it looks like its half a face.
Then I marquee select the uv's to move them, selecting uv's on both sides of the face, but only moving half the face.
Then when it comes time to mirror it back select half the faces in the 3d view of your model, convert to uv. Then scale it +x and move it back.

I dunno if this is the accepted way or if there is an easier way, but its what I do and it works.. :)

[womanonfire]

wondering if anyone else has another suggestion? i have half of a face layed out the way i need ... seems that since it is symmetrical it would make sense to just paint half the face and copy the map to the other side, but how to mirror the uvs to the other side of the face? is that just a bad way of going about things? hmmm.... :surprised

[18th_Devil]

well if its symmtrical u could just overlap the UVs.
just flip the uvs and overlap them.
its that easy :thumbsup:
or u can try to mirror it if u want to do more work :rolleyes:
but i haven't figured that one out yet :annoyed:

[beaker]

If your model is asymetrical(you modeled one half and then mirrored it and attached it). Then just delete the half without the UVs and remirror it. Then both sides will have the same UV's.

[womanonfire]

ah, i see! oke. will give it a go...

[Waboflex]

... or if you want to lay out UV's on one half only and mirror them (to save time and effort) so you can paint a full face, asymmetrical texture, you can do it like this:

Say you've got your UV's laid out nicely on the left half of a face, and you've mirrored and attached the geometry. At this point the two sides have the same UV's. Select all the UV's on the right hand side (in the front view's easiest), and in the UV editor hit r for the scale tool. Hit insert to go into pivot mode and holding down x (grid snap), move the pivot in the U direction so it's at the centre line of the face (you might need to change grid settings to get a gridline to snap to). Hit insert again to come out of pivot mode, and while holding x again, scale in the U-direction. You should be able to snap-scale the UV's so they're perfectly mirrored.

I suppose you could script it, but it seems a bit pointless since it only takes a couple of seconds to do.

Wabo.

[womanonfire]

as it turns out it worked exactly as beaker said. i had half a head with the uvs layed out the way i wanted... once i mirrored and stitched the head together the uvs were not only identical with the first side but aligned exactly on top of the first set. no tweaking required. hmmm... neat trick! :D

[GrafOrlok]

Beware though, If you are going to use bump maps you will get a negative bump on the mirrored half. Maya calculates bump-maps according to UV's so if they got a negative scale, bumps will be inside-out too.

[Waboflex]

Yeah I've seen that before but it's always been because of the geometry normals, not the UV's. The UV's themselves don't have a direction or +/- value for normals, they're just 2D information for mapping things. Bump mapping gets its 'in-or-out' direction from the geometry normals, so you should make sure all that normal direction business is sorted out first.

Wabo.

[GrafOrlok]

Yeah I've seen that before but it's always been because of the geometry normals, not the UV's. The UV's themselves don't have a direction or +/- value for normals, they're just 2D information for mapping things. Bump mapping gets its 'in-or-out' direction from the geometry normals, so you should make sure all that normal direction business is sorted out first.
:lightbulb No, I'm sorry but that is partly wrong. As I said: Maya calculates bump from the UV direction. When normals are flipped, the UV's are flipped too. But keeping your normals pointing in the right direction and having your UV's on top of each others (mirrored) your bumpmap will be inverted. Try for yourself...:p

3D studio MAX calculates from the Normal direction and not from UV's, but Maya does (and I think it's stupid).

[Waboflex]

Mmm. Yes, it seems you are correct Graf, sorry about that, all the cases I'd seen WERE because of geometry, I can't say I'd noticed this UV thing before. And yes, I think it's pretty dumb too. :hmm: I wonder why AW did it like this, it doesn't seem to have any useful purpose, and really just causes problems needlessly? I think I'll send a suggestion to Alias...

But the good news is that doing it like I suggested above must be doing just the right amount of flipping to get a correct end result. Or it works for me anyway. I'll consider myself lucky :D

Wabo.

[GrafOrlok]

I wonder why AW did it like this, it doesn't seem to have any useful purpose, and really just causes problems needlessly? I think I'll send a suggestion to Alias...
Agree totally!:curious:

[Abominable]

If your model is asymetrical(you modeled one half and then mirrored it and attached it).



Watch how word your ideas......asymmetrical means different on each side....symmetrical means the same on both sides.

Cheers :)

[beaker]

Abominable - my bad, I meant symetrical.


>>And yes, I think it's pretty dumb too. I wonder why AW did it like this, it doesn't seem to have any useful purpose, and really just causes problems needlessly? I think I'll send a suggestion to Alias...

It makes sense to me. UV's are just your mesh laid out on a 2d plane. If you lay them out upside down then the bump goes in the opposite way.

It's really easy to fix anyways. Just make a second shader with the same as the opposite side attached to it but just put an inverse node hooked to the bump.

[kiaran]

I'm running Maya 4.5 and when I delete and duplicate a symentrical model, the uv's mirror themselves, however the bumps do not invert themselves. ?!?!:shrug:

Guess I'm lucky.

[GrafOrlok]

Check your Normals then. I bet you they're inverted!;)

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