How would you unwrap this?

ned_poreyra

So, this thing. What is the proper way of UV unwrapping this for a game? According to the best AAA standards and all that. You can sketch your solution in MS Paint (where would you put the seams).

IxenonI

The only way to learn is to do your own tests with different layouts. That will teach you the pros and cons of each....

FrankPolygon

It depends on what you need it to do: How big is it? Are you baking normal maps to it? Are you using tile textures or a trim sheet? Will the UVs be packed with other objects, Etc. All of these factors will change how you need to approach it.

A few strategies that could be adapted to your specific needs: you can mix and match to fit.

First one: Contiguous with minimal seams. Some UV distortion on the inset geometry. Empty space on the sheet.

Second one: Split with minimal seams. No UV distortion and a uniform density. Empty space on the sheet.

Third one: Split with seams along hard edges. No UV distortion and uniform density. Less empty space on the sheet. Islands can be arranged to fit a trim sheet or tile textures.

ned_poreyra

IxenonI said:

The only way to learn is to do your own tests with different layouts. That will teach you the pros and cons of each....

None of my solutions were good so I came here to learn how better 3D artists would do this.

slosh

what is this for?  is it a small piece of a larger asset?  how close does it get to the camera?  assuming its a one off piece that gets its own texture sheet, I would detach every face honestly and have it be its own shells so you can bake bevels into all the edges.

ned_poreyra

Well, I might just as well share the actual problem. I modeled a Glock and I'm trying to do low poly and baking. I've worked for 5 years using procedural textures and triplanar mapping only, so it's a rather frustrating endeavour for me right now. I don't know what to do with those 'notches'.

It's quite problematic, because there is engraved text on the side and I want it to be nicely displayed in the UV map, so it's possible to make different skins for the gun in Photoshop by making changes to the texture alone.

FrankPolygon

Probably something like this. A lot still depends on whether or not your baking, smoothing groups, etc. If you keep it contiguous like this you'll probably want a little taper on the sidewalls of the slots to reduce stretching. Otherwise if you want parallel sidewalls, minimal stretching and hard edges you'll need to put seams around the slots.

You'll have to look at the examples and experiment to see what works best for what you're trying to do.

poopipe

for the slide...
it's a box so box map it, tear off any faces that are too distorted and map them flat separately. 

this works for basically anything 

ned_poreyra

FrankPolygon said:

How did you do that? When I unwrap the same mesh the UVs get all distorted.

poopipe said:

for the slide...
it's a box so box map it, tear off any faces that are too distorted and map them flat separately. 

this works for basically anything 

The problem is I don't want to separate distorted faces, I want the UVs to be continuous and not distorted at the same time, like FrankPolygon did.

Alex_J

Just try both ways. Then you'll know. both these guys are professionals, so if you learn each ones methods you'll be better off.

the best hting about digital art is you can try almost anything non-destructively. No other medium you can do that in. So take advantage of that fact.

ned_poreyra

Alex Javor said:

Just try both ways. Then you'll know. both these guys are professionals, so if you learn each ones methods you'll be better off.

I'm getting different results. I made the same mesh as FrankPolygon, I've put seams in the same places, but my UVs are distorted after unwrapping and his aren't.

Alex_J

post screenshots, shoudlnt' be too hard to troubleshoot

FrankPolygon

ned_poreyra said:

How did you do that? When I unwrap the same mesh the UVs get all distorted.

The cut outs are causing stress so it skews the unwrap. Unwrap the flattest parts first. Pin. Unwrap the rest.

As a side note it kind of looks like you're using Blender? When you run an unwrap there's two methods: angle based and conformal. For this type of unwrapping conformal will provide better results. If you encounter any other issues post screen shots. Hope this helps!

ned_poreyra

FrankPolygon said:

 Unwrap the flattest parts first. Pin. Unwrap the rest.

Thank you, that's the part I didn't know about. Pinning.

poopipe

ned_poreyra said:

FrankPolygon said:

How did you do that? When I unwrap the same mesh the UVs get all distorted.

poopipe said:

for the slide...
it's a box so box map it, tear off any faces that are too distorted and map them flat separately. 

this works for basically anything 

The problem is I don't want to separate distorted faces, I want the UVs to be continuous and not distorted at the same time, like FrankPolygon did.

Frankpolygon's UVs are nice but they are not undistorted.  If you draw a straight line along the length of the slide it will have wobbles in the grooved areas. 

I imagine it took a few minutes of manual cleanup to achieve those results from the initial flattening 

FrankPolygon

Ned hasn't confirmed but it looks like he's using Blender and the stock UV tools there are somewhat limited. Below is the result of a Cube Projection unwrap in Blender. Compared to other packages it's not that usable. Smart UV Projection might work a little better but it's still not ideal.

Slight distortion on a small part of the model is a downside to the contiguous unwrap but it's also going to be easier to overlay text and other patterns. So there's something of a trade-off here. If the model had sharp edges and was baked down the UVs would need to be split there anyway. The curved surface on the model also introduces a perceived distortion which changes based on camera angle.

The examples below are more representative of the actual geometry. Each has it's own set of trade-offs.

The first has minimal distortion but requires projecting or manually splitting and aligning the text overlay. The second has some distortion that's visible at extreme angles and the geometry is slightly tapered but it's easy to overlay text on. The third has minimal distortion but overlapping UV's and wouldn't be suitable for baking but it'd be easy to overlay text on. Different acceptable use cases for each of these.

Granted the third one is a little too janky but there are cases where it could work. Without baking, the overlapping sections could be split off and the rest left in place. Something of a compromise between the first and the second. Again: it's all dependent on other factors.

Here's what my process looks like in Blender's UV editor. It's a progressive unwrap so it starts with a central flat area and I work out from there. Each iteration is two keystrokes (Unwrap and Pin) + a mouse click to select additional geo. That's a total of 8 keystrokes and 4 mouse clicks. If I separated the slots  with seams then it's even less work since it all unwraps evenly at step 2. No re-work needed.

After learning about pinning, it looks like Ned got most of the way there on his second try.

When working on low poly meshes I'm always adding the UV seams and sharp edges as I go. That way the final unwrap is fairly straightforward. I think it's all about understanding how the geometry is going to unwrap and planning accordingly. If I have to do manual re-work then it just means I didn't plan ahead or I didn't have a solid understand of what was going to happen with the seams. Advanced UV tools are great (when available) but without the fundamentals it can just lead to a bigger mess.

I agree with Simon: there's a number of ways to approach this and each has it's own merits so it's something you have to try on your own. I also think that exhaustive examples that shortcut having to experiment and learn on your own aren't the greatest value.

ned_poreyra

Yes, I'm using Blender. Thank you for all the awesome advice.

You said that UV tools in Blender are somewhat limited. Can you tell me which program has better UV tools and in what way? After learning about pinning and selective unwrapping I don't really feel like I'm missing on anything.