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View Full Version : UVW Unwrap, saved UVs, changing mesh after saving the UV


ai_jai
01-12-2005, 10:03 AM
Hi all,

Ive been texturing a face for a while using the same mesh, and tweaking the UV in UVW Unwrap 'EDIT'. Now ive got the unwrapped mesh just right, I need to add mesh for a 3d ear, because at the moment it is just a texture of an ear on a flat mesh, now i need to add the 3d ear to my mesh the UVs in my EDIT UVW Unwrap have resest themselves and i need to do all my EDIT UVW Unwrap tweaking all over again, does anyone know a way round this?

Idealy I want my saved UV to stay the same, and just the easr mesh thats different, add itself into MY saved UV. Any ideas anyone?!

Cheers

ai jai

robinb
01-12-2005, 12:31 PM
Yep, this is easy. First take your uv unwrapped model, collapse it to an editable poly model. Then attach your ear model (or model the ear at this stage), then apply another unwrap uvw modifier and open the edit window. The original model should still be there with the ear uvs overlaid on it. Just select and unwrap the ear uvs.

ai_jai
01-12-2005, 12:58 PM
Thanks robinb, it certainly worked for keeping my uv's, one problem ive just found though...i had to delete the symmetry modifier before i collapsed the stack to editable poly, so even though the UV's are now fine and how i want them, when i put a symmetry modifier on my editable poly model, and then put a UVW unwrap on top of symmetry it isn't showing the resulted symmetry in the EDIT window of UVW Unwrap. I need Symmetry to work for the object obviously, but I also need it to work in UVW Unwrap so I can resetup my Material ID's that got lost after collapsing the stack like you said.

Thanks again for the reply, i did do a bit more research and one way round it was to just add an edit poly modifier at the top of the stack instead of collapsing it, but that meant anything i did i would have to do again on the other side, and basically it was just getting stackerific and confusing. So this way seems like the best solution. Theres just this wierd thing happenin with my symmetry now, it displays the symmetry in the viewport, but just not in the EDIT window of UVW Unwrap....

Any more pearls of wisdom? :thumbsup:

Edit; Blimey, things may have taken a great big U-turn for the worst. I added a UVW Mapping modifier above the symmetry modifier and added a UVW Unwrap ontop of that to see if the EDIT window in UVW unwrap would display the symmetry, it displayed the symmetry, yay....woohoo...you would think! but it also rest the UV's i've been trying to keep all along....SO....it seems i cant add another UVW Mapping modifier because it will reset my UV's, but Symmetry mirrors the object AND the texture applied to that half of the face (model). So I really need another way to make UVW Unwrap display the symmetry.

robinb
01-12-2005, 01:29 PM
What I do for symmetrical models is to collapse the symmetry modifier before starting the unwrap. Then I'll delete the bits of the model that I plan to mirror (say one arm and leg and one side of the head). Then I'll only unwrap these remaining parts. Then I'll collapse the stack when they're unwrapped to my liking, then clone the bits of model I plan to mirror to a second model (detach as clone). Then I'll mirror them (using the mirror modifer to prevent the potential problems with negative scale you get using the regular mirror tool), reattach them to the first mesh and re-weld all the verts.

The reason I do this is that I don't like to have the middle parts of the model using mirrored texturing (the face in particular but also the torso tend to look a bit weird with mirrored texturing).

Sometimes I'll do the deleting, detaching cloning and mirroring after the first half of the model is mapped, but it's cleaner this way.

There's other reasons not to keep the symmetry modifier on the stack when the modelling is finished. It can affect vertex order so can cause problems with morph targets for instance.

I'm not using max 7 so the edit poly solution isn't available to me. I'm sure it would work instead of all the collapsing, but you'll have to be careful about the stack order and what was unwrapped at each stage. I like to keep my stacks as flat as possible. I only tend to keep them live if I'm doing something procedural (like a lofted line maybe) or if I'm doing stuff that needs it like animated characters.

Hope some of that helps. :)

ai_jai
01-12-2005, 01:53 PM
What I do for symmetrical models is to collapse the symmetry modifier before starting the unwrap. Then I'll delete the bits of the model that I plan to mirror (say one arm and leg and one side of the head). Then I'll only unwrap these remaining parts. Then I'll collapse the stack when they're unwrapped to my liking, then clone the bits of model I plan to mirror to a second model (detach as clone). Then I'll mirror them (using the mirror modifer to prevent the potential problems with negative scale you get using the regular mirror tool), reattach them to the first mesh and re-weld all the verts.

Yeh it deifinitely helps, hor the future at least. I've tried this little process after collapsing the stack to see if using mirror instead of symmetry would make UVW Unwrap EDIT display the whole face and not just half, but it doens't. Think I'm just gonna have to start from scratch, and go through your little process to try it out as "good practise".

Cheers:D

ai jai

robinb
01-13-2005, 09:12 AM
Edit; Blimey, things may have taken a great big U-turn for the worst. I added a UVW Mapping modifier above the symmetry modifier and added a UVW Unwrap ontop of that to see if the EDIT window in UVW unwrap would display the symmetry, it displayed the symmetry, yay....woohoo...you would think! but it also rest the UV's i've been trying to keep all along....SO....it seems i cant add another UVW Mapping modifier because it will reset my UV's, but Symmetry mirrors the object AND the texture applied to that half of the face (model). So I really need another way to make UVW Unwrap display the symmetry.

The UVW map modifier will be applied to the selection in the stack (it'll be applied to the whole model in your case by the sounds of it so it overrides the mapping lower down the stack or the existing uvs). You can put a mesh select, edit poly modifier or whatever on it, select some faces and pass them up to the uvmap modifier higher up the stack. The stack can be confusing for things like this which is one of the reasons why I don't tend to use it in this way.

The reason you only see half the model in the uvunwrap edit window when you've used symmetry is simply that the two halves of the model share the same mapping coordinates so they're on top of each other. You should be able to select the faces on one side of the model and move them away in the edit window (you might have to 'detach edge verts' if you've welded the uvs) and mirror them if you want for instance to have both halves of the face mapped separately. Make sure it's synced to the viewport so you can see which faces and verts are selected in both windows.

ai_jai
01-13-2005, 09:21 AM
The reason you only see half the model in the uvunwrap edit window when you've used symmetry is simply that the two halves of the model share the same mapping coordinates so they're on top of each other.

DOH!!!...makes sense really. I'm gonna start from scratch anyway now, I know exactly what i need to do when I get to the EDIT UVW Unwrap stage again so it won't take long, and i have quite a bit of of model tweaking to do (lips, eyes, forehead) so i'll just start a fresh. Thanks for for ya help robin:)

robinb
01-13-2005, 11:24 AM
No problem. Glad to help :) I know how complex the whole mapping process can be to learn. It took me ages to get my head round the concepts way back when I was learning. Now it's second nature, but it's still a weird thing to have to do when I think about it.

ai_jai
01-13-2005, 11:40 AM
Well its definitely not second nature to me yet. its my 1st time usin cylindrical to texture, and the 2nd time ive textured anything. But Its all pretty logical so far. Cant wait till the day it is second nature though! Cause...you don't want everythin in ya life to be second nature to you, otherwise they'll be no challenge....and not much fun. Think this is something I wouldn't mind bein second nature to me, Not many CG things are so this can be my 1st :)

robinb
01-13-2005, 12:25 PM
Oh don't worry, there's always challenges. I prefer it when the challenges are artistic rather than technical. Good luck, CG can be a lot of fun when it's not being a huge headache.

ai_jai
01-25-2005, 12:59 PM
Hi all,

robinb, I thought you might be interested to hear this.

Ok, for anyone who's read this thread and understands the problem i had, I've just tried something out real quick after semi fixing this kind of problem, to find you can solve it ALL TOGETHER! So if your interested to know how...read on.

The problem I had a few weeks ago was adding a propperly modelled ear to my head mesh which currently only had a flat "cheap" ear. Unfortunately in Max as soon as you edit the vertex count of the model max resets the UV's because it cant understand the changes you've made and update the UV's accordingly. It even reset my UV's when welded 2 vertices.

So, for adding the ear to the model i just had to bite the bullet and start over in EDIT UV's, but when i realised i needed more neck and the back of her head as the hair is now shorter than originally planned. So as the de-ja-vou kicked in i really really REALLY didnt want to have to redo my EDIT UV's all over again, and modelled the rest of the head i needed as a seperate object. Then I textured it using uvw mapping (cylindrical, same as the original face/head object), UVW Unwrap and symmetry , with symmetry at the top of the stack. I edited the UV's with the object using the same texture as the face/head object, then i painted some more skin on the texture where i set the UV's for the neck. Now both objects are using the same texture map and have their own UV coordinates setup, collapse the stack on both models, then attatch one object to another and weld any points that need to be. Max remembers the UV's from both objects so when you add a UVW Unwrap modifier on the 1 resulting object it unwraps the UV's of the combined object.

If i knew this when i needed to add the ear all i had to do was collapse the stack of the face/head object, delete the polys of the flat "cheap" ear the propperly modelled ear will replace. setup the UV's on the ear as a seperate object, using the same texture map as the face/head object, collapse the stack on the ear object, attatch the ear object to the face/head object, and add UVW Unwrap to the resulting object, and the UV's for the ear object will just add themselves to the UV's for the face/head object.

This is the resulting EDIT UV.
http://www.andyhowat.com/UVWUnwrap_solved.gif
The UV's inside the yellow are the UV's setup on a seperate object, then collapsing the stack and attatching to the rest of the face/head object. The UV's outside of the yellow are the original UV's of the face/head object.


Hope this is useful for someone, its definitely something i can keep in mind for the future, and means i'll never have to start all over again in EDIT UV's.

Cheers

ai_jai

robinb
01-25-2005, 01:29 PM
Yeah, that's basically what I was getting at in the first post. Except you don't actually need the ear as a separate object, you can do all that to it when it's attached to the head. It does keep things a bit under control to work on them separately though.

But you never know til you've tried it yourself. ;) Glad you've got to grips with it.

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