Seem placement options?

diglett

Hello I just unwrapped a model, how is this looking, circled red is symmetric.. can I overlap symmetrical parts? how close does the overlap need to be? is there a good method for overlapping? is there a good method for using up as much space on the texture map as possible? thanks!!

Revel

What's your target texture size? even for a 1k map it looks like still too much padding. For your question how close the overlap need to be, well, it has to be right ontop of each other for it to be overlapped. You can do that by simply add Symmetry modifier to the mesh.

diglett

How about this one? I applied overlapping as best I could it's not perfect though, does that matter? It is a 1k map btw. also I had a bunch spare triangles (top right blue mess) and I just grouped them together, does that matter? I use 3d coat for texturing and photoshop for tweaks.

musashidan

The purpose of overlapping UVs is to save valuable space on the sheet. When you have multiple identical elements you place them on top of eachother in the exact same coordinates in UV space. This is called stacking. You want to ensure that the islands are placed exactly on top, rather than eyeballing.

When you have a symmetrical mesh that you want textured symmetrically you overlap the UVs to effectively double your texel density. If you are baking, however, you need to temporarily offset your overlapping UVs out of 0-1 UV space to avoid Z-fighting and mesh centreline artifacts.

Unwrapping is an art in itself and really requires that you keep doing it until you get an efficient workflow in place. Most people hate it but I actually enjoy doing it. It's just like a puzzle. The more you do it and the more you run it through your pipeline the better you will understand the why and the how. Knowing when and where to cut seams. Knowing how much distortion is acceptable. Knowing how it affects your bake. Knowing the quickest and cleanest way to unwrap different forms..........etc.

As for packing, the best method is to do it manually. Even though packing algorithms have gotten smarter(dedicated tools like ipackthat) they are not smarter than a human brain. The most efficient way to pack is to do it yourself.

My approach to packing is like my approach to digital sculpting or hard-surface modeling: macro to micro.

Because the end goal is to 'tetris' multiple different shapes into a square, always think square as you pack.(unless you are authoring 2:1 textures, obviously) This way, as you get closer to the last remaining islands to pack, you should have an evenly spaced row of empty space along the side and top of the texture sheet which will allow you to scale up your islands at the end and gain an extra percentage of space used.

diglett

Okay that all makes sense, I see it the same way. Like a very difficult puzzle that can almost always be improved.  I can see the fun in it even if I'm not very good at it as a beginner. But to note the way I stacked the above symmetry is correct, no?

Revel

Overlapping a symmetry uv is good to get a more higher texture density on other unique bits, but don't over do it cus you might get an artifact of what we call 'butterfly effect'. It's when you can see the pattern on you texture mirror right at the center of your mesh.

For hands/ legs for example it's hard to tell since they're separate from each other, but for a face you might see a line at the center of the face (not a seam line) and the skin pores mirrored from one side to another.

Other example would be a wrinkle on a clothes, it looks fake when the wrinkles perfectly mirrored from one side to the other.

For your question; are you mentioning about the face uv? no you didn't overlap the face, since left and right side of the face is occupying different coordinate in the uv space. If you want to overlap that, you'll end up with just half of the face appear on the uv.

I believe you're using Max right? you can try add a Symmetry modifier on your mesh and add an Unwrap UVW modifier again ontop of that, you'll see half of your uvs are not there, it's because they are flip and sit right ontop of it's other half and that's the overlapped uvs. Now you can scale up your uvs bigger and gain more density, but the catch is that you can't have a unique detail between left and right on those overlapped uvs.

diglett

Revel  okay cool I will try that, thanks a lot! dude major props super helpful. good job A+ help everyone should take note of your ability to give insight.. can this be featured on the front page of polycount so everyone can see how insightful you have been. thanks

Thane-

Rip: old normal map wiki. Could have just linked you there to answer all your questions, it was great, but now its just mainly a bunch of links to other stuff new people must decipher. You do know polycount has a wiki though? Its still really helpful and contains the most accurate info generally, IMO.
This would be a good page to have bookmarked for your 3d modelling troubleshooting.
http://wiki.polycount.com/wiki/Normal_Map_Modeling

diglett

@Thane-
I'll check that out, thanks.. btw I also look into my questions before asking them and normally I spend way too much time on trying to figure it out

Eric Chadwick

Thane- said:

Rip: old normal map wiki. Could have just linked you there to answer all your questions, it was great, but now its just mainly a bunch of links to other stuff new people must decipher. 

You probably want this page, more high-level overview, and you can dig into the topics you want.
http://wiki.polycount.com/wiki/Texture_Baking

diglett

thanks guys