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Texturing outside yet inside boundries

Started by SickAlice, December 15, 2014, 08:38:45 PM

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SickAlice



^ meaning that.

I run into this often with models made for marketed games. This one is from Marvel Heroes. The artist (can't recall though they pop in at the ZBrush forums, some real neat previews over there) does this for any mesh. For those that aren't familiar the parts (vertices/polys/faces) that are mapped outside of the image are actually mapped on the image. This example is easy enough to tell how as the bit off to the side is a mirror of what's on the left. Sometimes this stuff is all over the place. Sometimes it's out of view in whichever direction, sometimes it's WAY out of view somewhere. Other times the verts that aren't on the image itself do not match up with the ones on the image. In that case they are for separate parts/shapes. I never align a texture like this. I never learned how for one but two I think it would only confuse me and/or skinners. The questions I have:

1. What's the technique actually called? Research would be easier if I knew where to start looking.
2. Methods for " correcting " it? Technically it isn't wrong as is. However if your using an available model for Freedom Force the tenancy is to reposition it's texture coordinates for easier skinning and of course so you have less .tga's/.dds's in the skin directories. When it's like the above it's simple enough. Grab the verts on the right and move them, overlapping them with the matching on the left. That is if the vertices aren't welded together, in this case they are. When they're welded of course when you select them you also select the adjacent they are welded to and likewise for moving them which is no good as in the example the left side verts would be pulled out of position. Also is the case where the mapping outside isn't a match for anything on the texture. Normally in that case I try and use my eyes to see where it is mapped then move it to that position but that's a tricky thing to do. Also a person can just remap the whole thing however then the original texture more often than not will no longer be a fit.
3. Also and I've noted that if you just manipulate it all together, like say there is a smaller version of the above texture and you shrink all of the texture mapping into that smaller area the verts that were outside will lose their coordinates and instead map to exactly where they are sitting now. Why? Is there a way around it?

grenadier

It sounds like Multi-Tile Mapping instead of the standard UV Mapping.

Here's an explanation and examples of it.
http://area.autodesk.com/tutorials/part_1_multi_tile_uv_mapping

There's so many ways to mapping.  It's all subjective and dependent on the mesh.

- Gren
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SickAlice

Thanks. Still not finding much concrete about it (I don't use Maya so that's part of it though). I guess my thought was this: If faces are in fact mapped to a specific area on the texture despite to the naked eye being located somewhere else off it (my understanding is the main function is to have less instances where the texture is " runny "), then there should be a way to bring them back to/directly clamped to the specific coordinates they are textured to if that makes any sense. As it is I'm working with something right now and the method I'm using is to break up the mesh into pieces by each section and manually move the faces to where they appear to be textured (I have a second untouched copy of the model in the workspace to use as a map). The problem with the way I'm doing it is it's very time consuming and of course leaves a big margin of error. I know it's all a shot in the dark but the logic seems sound.

grenadier

#3
It doesn't matter if it's Maya, Max, Blender, or whatever, it's the technique and the reason for it's use was the point I was getting at. 
Here's a tutorial as to why and how to use it in Blender:

https://www.youtube.com/watch?feature=player_detailpage&v=_yczciMYv4Y
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Until Further Notice,  

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SickAlice

Thanks. I'll have to watch it later. My wifi allotment is up for the month and that's a long video.
The question though and maybe present in the link you gave (I didn't find anything in the former) is can it be reversed, or inverted. Not certain what term to use but easy enough to say can the mapping be moved from it's position outside the texture to where it's assigned directly on the texture? Sorry if I'm not making any sense with that but I'm lost as to what they right terminology is. I mean outside of grabbing each vertice and moving it manually of course.

grenadier

#5
Quotecan it be reversed, or inverted

Yes if I'm understanding the question correctly.
To do this in Blender:

1. Go to the UV Editing screen.  Two screens should appear showing the same mesh.  Left screen (UV map Screen)  Right Screen (Edit Mode Screen)
2. Switch the right screen to Edit mode by hitting the tab key.  Note: Make sure it is on edit mode.
3. On the Right screen, Select a few polygons that you want to invert.  They should be highlighted. Notice they will show on the Left screen.
4. Go to the Left screen, and Select All. They should be highlighted.
5. At the Bottom of the Left screen, you should see UVs.  Click on it to open the menu.
6. Find Mirror.  Choose either X or Y axis.  You can now invert it or flip it.
7. To see how the entire map looks with your changes, go to the Edit Mode Screen and select all using the 'A' key.
8. If you don't like it, do an Undo (Ctrl+Z) until you're back to where you want to be.
7. Once you're satisfied, export the layout as a JPG file and use it as the skin.
    Use this as a way of referencing where your current uv map layout is just in case you want to make adjustments.

Hope that helps.


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Until Further Notice,  

No Requests will be be accepted.



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SickAlice

Thanks. Didn't work but I'm sure that will be useful somewhere else. The verts that were outside of the image remained so, or technically. The way the model in question is mapped is that the vertices sitting outside the image are the mirroring each other already. So inverting them just made them play musical chairs essentially and end with the same type of result that it began with where the verts are still sitting outside of the image. The desire is to undo that all together for if no other reason than it makes things messy for skinners down the line and so I can map multiple different objects to one .dds rather than a bunch.

SickAlice

I think I thought of a better way to explain this just so as not to leave it flapping in the wind. This image isn't real, just something I dopped up in Photoshop for example purposes using your female mesh's head. We'll assume the actual texture is done symmetrically here.



So figure A would be an example of the mapping method in question. Figure B of course the method we'd use more often for Freedom Force.

The idea then is to get A to B. Should be pretty easy, just grab each side of A and move them to line up with B. Not going to work. By grabbing on side on A all of the adjacent vertexes on the mirror side will also be selected and those faces moved because they're welded together like a good game mesh should be.

So using the method you put here I mirror A instead? Right though. Then those two sides just change places with each other and the end result looks the same anyways.

The notion I'm having is in A despite being placed off in the grey/dead zone of the texture they are in fact mapped where B is and therefore the mesh contains that information in A, but how to use that information to make A into B? At this point I've seen no documentation on a process nor any that suggests it can be done, though I'm not one to conceded to impossibles. It does seem though that no method is about to date but I just wanted to make sure as it would save me lots of time (would've knocked 4 days off the latest project actually).

* Luckily I just finished the one I wanted this for currently the long way. And I'm glad I did in a way. As it turns out Nintendo mapped there own game models wrong for some reason, where some parts weren't were they should be or just overlapping where they need not so this gave me the chance to clean up the final result.