Best Method for creating partially mirrored textures?

Jensen

Hey all :P

So say I want to mirror UV's and textures for certain parts of a symmetrical mesh, but not others, what is the best way to go about this?

I've thought long and hard about it, and the method I've come up with is tedious and very long, and seems rather ineffective.

so Here is the model i'm trying to partially mirror:




And here's an image that represents what I want to mirror and what I don't want to mirror:




So basically I want to leave the front and a portion of the back, to lessen the appearance that I mirrored the textures. However where I get stuck is when I try to fix the seam of one side of the mesh, the mirrored part is updated as well, and then it no longer matches up on the other side?

It's a difficult question for me to ask without my confusing myself, so hopefully someone will be able to understand me :P

Thanks!

3Drobbo

hmmm, im not to clear on the problem your having, or if its the right way to texture this helmet, I would proberly just unwrap the hole thing with out mirroring it. Or if its a game thing, using a 2nd UV for decals and blending them in game etc.

But if you want to do it this way, what i would think i s to unwrap half the head, and then symmetry the model so ur unwrap is mirrored. Then select the areas on the model you DONT want mirrored and unwrap them seperatly but flipping them and repositioning them in ur map. does that make sence?

good luck

Muzzoid

Another option is to cut the unique detail off and make it a seperate mesh, and place it where it should be on the final. That way you have a symetrical head with a sepererate asymetrical detail.

It can work well in some situations and not so well in others though.

MoP

Jensen wrote: »

However where I get stuck is when I try to fix the seam of one side of the mesh, the mirrored part is updated as well, and then it no longer matches up on the other side?

I don't really understand this part?

Basically it sounds like you have the right idea - delete the geometry for the parts you want mirrored (as you showed in your first image), then unwrap all this remaining geometry.

Surely once you have completed this, all you have to do is select the geometry to be mirrored, and duplicate it across to the other side?

I can only think that you have an "instance" version of the mirrored mesh, since this would mean that the UVs of both sides update when you edit one. You should do a copy of the mesh, not an instance, since that will allow you to edit the UVs of the copy individually.

However even this doesn't make much sense, because you shouldn't have to edit any UVs at all once you've unwrapped the original set of geometry. All you have to do is copy and mirror the polygons, and then bingo, your whole model is unwrapped.

I don't see the problem here, really, it sounds like you're adding some strange unnecessary step after you've already finished unwrapping everything?

Mongrelman

The way I do it involves making the uv layout symmetrical for the non-mirrored part, usually by uv mapping half the model, then mirroring that geometry (and uvs) and welding in the middle, so the uv layout is exactly symmetrical.

Then you texture half, duplicate the texture (or whatever parts you want), duplicate the uv map and flip both the new UV map and texture layers horizontally (or vertically, depending on how you did your uvs). Then you just shift these duplicated layers until the 2nd uv map lines up with the original and delete everything you want from the duplicated texture layer except over the seam area. This should give a perfect alignment.



So in this case I'd say:

uv map the helmet how you want, making sure the uvs down the center of the face area are perfectly vertical.

Then delete half the model.

Mirror the geometry of the face area (the section that won't be sharing uvs) and make sure you also flip the uvs of this new gometry horizontally.

Move the uvs of this section so that they line up along the middle, then weld the verts and uvs

Then you can mirror the rest of the head geometry and leave the uvs alone, so they will be shared.


Hopefully that all made something approaching sense, I can't to any pictures as I'm away on holiday with a laptop.

Jensen

Thanks for all the help guys!

I really like the method you posted Mongrelman! This technique seems to be the best answer for a mirrorable mesh where you don't want some parts mirrored

I have a few questions about making it exact tho :P

1. how do you make sure you match the texture up with the moved UVs after you mirror and move it? Also is there a way to change the mirror axis, so when you mirror it, it flips to exactly where it needs to be?

2. If you were working with a model that wasn't completely symmetrical but had some parts that were symmetrical would you do the same thing? For example, on a model like this:



I wanna mirror the legs say. So would the process then be:

1. Set up what the final UVs will be like (everything not mirrored except for the legs. Then take off the top of the mirrored legs, and add it to the rest of the body, so the transition is smooth)

2. Create the temporary UVs that mirrors all possible mirror-able parts, and texture that area.

3. Cut off the buffer area, and mirror that. Then take the torso (since it will be connected to the mirror part) and attach it to the mirror-buffer.

4. Mirror the texture and match it up to the UVs

5. Continue texturing, and do not go over the mirrored-seam area.

lol ok now I'm confusing myself! Does this make any sense at all?

again thanks for all the help!

MoP

Well, I don't know why you keep putting the "texture that area" part in - you shouldn't need to texture stuff before you've finished UV-mapping. I mean, you could, but it's usually not the best way, since you may need to move UVs round later and that might mess up any textures you've done that far.

For unwrapping something with mirrored legs like that, I'd just delete the geometry that was going to be mirrored (ie. the left leg for example), then unwrap the whole mesh, then duplicate and mirror the right leg geometry. No worries. Not complicated.

Edit: Image just to be clear:

Mongrelman

As MoP said, texturing after doing the uvs, no temp uvs needed.


By having exactly symmetrical uvs, in photoshop put your uv map on the top and set it to screen or multiply, then duplicate your texture, and also duplicate the uv map. Move the duplicate uv map layer to the top so it is over the first one. Select the duplicate texture and duplicate uv map layers and flip them. Then you move both together until the duplicate uv map layer matches exactly over the original uv map layer, for the part of the texture you are focusing on, in this case it would be the face area. Best to zoom in too, as it helps make sure you have it exactly lined up. Then you can just delete the duplicate uv layer, and everything in the duplicate texture layer except the area around the uv seam.


But for parts that will be sharing uvs just do as MoP posted, it's very quick, easy and perfect alignment.

I'll try to put a few images togther to better explain once I get home, which will be about a week.

Jensen

Fantastic you guys thanks a ton for the quick paintover MoP and for the info on the perfect lineup Mongrelman! I think I finally have my head around this concept :P Which is good considering i was straining myself trying to think of a perfect method XD Cheers!