HELP U.V

marco_3D_artist

Hello, guys, I'm working on this grenade but  I don't sure if My UV layout is good or need some improvements, especially in the body part.
Thank you at all! 

Ashervisalis

Hey, so you really want to flip those red UV islands so they're blue as well, and you'll want to get all your UVs in the 0-1 space. Your packing looks decent

marco_3D_artist

Ashervisalis said:

Hey, so you really want to flip those red UV islands so they're blue as well, and you'll want to get all your UVs in the 0-1 space. Your packing looks decent

Hey Thank you for your answer,  I thought that the body of the grenade was badly unfolded. 

Brian "Panda" Choi

UV packing could be way better

Ashervisalis

@Brian "Panda" Choi  Can you elaborate? Aside from the head of the grenade being outside of 0-1 space, it seems decently packed.

poopipe

The mirrored stuff is fine -  reuse is good - the post above about that is simply wrong

Straighten the body part out. 
Make sure everything that could reasonably be straight is straight - wobbly shell boundaries lead to aliasing artefacts. 

I don't think you've got enough padding - you need a minimum 8 pixels at 2048, 16 at 4k etc. 

 The packing isn't bad, assuming everything is at a consistent scale. You could probably re-use some more space but it's not going to let you drop to a smaller texture so not much point

musashidan

Ashervisalis said:

@Brian "Panda" Choi  Can you elaborate? Aside from the head of the grenade being outside of 0-1 space, it seems decently packed.

You can clearly see that those dupe islands have been offset for baking.

OP - you should straighten out all those rectangular islands. I can see aliasing on all of them. This can transfer to your NM. Good practice to always straighten island borders where you can.

Ashervisalis

@musashidan Those red UV islands don't need to be flipped? Every time I have UV islands like that, the faces end up flipped for Substance Painter, and Painter's back face culling makes it so these faces don't show up unless you're looking at them from the wrong side of the face.

Alex_J

you probably have that idea because you are doing environment art, using tileable materials. For non-tileable materials flipped faces don't make a difference. I regularly flip shells if its gonna make them fit neater and I know they aren't gonna need any tileable texture or pattern applied to them.

also a meshes face's normal direction isn't tied to the UV's. You can reverse the normals all you want -- doesn't change the orientation of UV shells.

also, one more tip, if you are working with single sided meshes in painter and want to see both sides, use the alpha test or alpha blending shader. that will display both sides.

Ashervisalis

Hm. I just tried to replicate the issues I got in Painter before with these flipped UVs, but couldn't replicate it. Maybe I'll bring this up when I have this issue again.

marco_3D_artist

poopipe said:

The mirrored stuff is fine -  reuse is good - the post above about that is simply wrong

Straighten the body part out. 
Make sure everything that could reasonably be straight is straight - wobbly shell boundaries lead to aliasing artefacts. 

I don't think you've got enough padding - you need a minimum 8 pixels at 2048, 16 at 4k etc. 

 The packing isn't bad, assuming everything is at a consistent scale. You could probably re-use some more space but it's not going to let you drop to a smaller texture so not much point

Thank you for your help Poopipe! I'll make the UV more straight and also check if I have enough Padding!   I'll share my resoult 

marco_3D_artist

musashidan said:

Ashervisalis said:

@Brian "Panda" Choi  Can you elaborate? Aside from the head of the grenade being outside of 0-1 space, it seems decently packed.

You can clearly see that those dupe islands have been offset for baking.

OP - you should straighten out all those rectangular islands. I can see aliasing on all of them. This can transfer to your NM. Good practice to always straighten island borders where you can.

Thanks, for you to I'll make those island more straight

Thanez

I can clearly see a discrepancy in texel density between the fattest part of the body and the rest of the model. I would either manipulate the uvs to be fatter and taller in the middle, like so:

Or do a texture hack to work around that. If you use triplanar texture projection to get your base texture defined, you'll transfer the density discrepancy to affect sharpness only.
I did both of these tricks to minimize errors when I did this (disclaimer, super-duper old work): http://skins.thanez.net/frag/frag_realtime.jpg

As others have said, your edges should be straightened, as skewed edges create pixelated issues all over when you're baking straight geometry.
Can't see if you did it here or not, but it's also a great idea to clump equal or similar materials together because they will be blurred into eachother at higher mip levels.

marco_3D_artist

Thanez said:

I can clearly see a discrepancy in texel density between the fattest part of the body and the rest of the model. I would either manipulate the uvs to be fatter and taller in the middle, like so:

Or do a texture hack to work around that. If you use triplanar texture projection to get your base texture defined, you'll transfer the density discrepancy to affect sharpness only.
I did both of these tricks to minimize errors when I did this (disclaimer, super-duper old work): http://skins.thanez.net/frag/frag_realtime.jpg

As others have said, your edges should be straightened, as skewed edges create pixelated issues all over when you're baking straight geometry.
Can't see if you did it here or not, but it's also a great idea to clump equal or similar materials together because they will be blurred into eachother at higher mip levels.

Thank you Thanez for helping me really appreciate it I did what you told me and I got this result: hope I did  right as you told me.
Also, I'm fixing the edge padding as the other guys told me

marco_3D_artist

Hello, thanks to everybody for the feedback I share with you my result.

poopipe

Thanez said:

I can clearly see a discrepancy in texel density between the fattest part of the body and the rest of the model. I would either manipulate the uvs to be fatter and taller in the middle, like so:

Or do a texture hack to work around that. If you use triplanar texture projection to get your base texture defined, you'll transfer the density discrepancy to affect sharpness only.
I did both of these tricks to minimize errors when I did this (disclaimer, super-duper old work): http://skins.thanez.net/frag/frag_realtime.jpg

As others have said, your edges should be straightened, as skewed edges create pixelated issues all over when you're baking straight geometry.
Can't see if you did it here or not, but it's also a great idea to clump equal or similar materials together because they will be blurred into eachother at higher mip levels.

That sort of layout can lead to nasty aliasing at the seam and I'd generally advise against it - especially in production where mipping and texture compression play havok with your carefully created maps. 

In the case of the grenade body I would map it cylindrically and then fix the vertical distortion as much as possible by shifting whole rows up&down.

In a world where texturing is done with bakes and 3d paint apps it makes sense to prioritise bake quality and LOD support over maintaining square pixels. 

marco_3D_artist

poopipe said:

Thanez said:

I can clearly see a discrepancy in texel density between the fattest part of the body and the rest of the model. I would either manipulate the uvs to be fatter and taller in the middle, like so:

Or do a texture hack to work around that. If you use triplanar texture projection to get your base texture defined, you'll transfer the density discrepancy to affect sharpness only.
I did both of these tricks to minimize errors when I did this (disclaimer, super-duper old work): http://skins.thanez.net/frag/frag_realtime.jpg

As others have said, your edges should be straightened, as skewed edges create pixelated issues all over when you're baking straight geometry.
Can't see if you did it here or not, but it's also a great idea to clump equal or similar materials together because they will be blurred into eachother at higher mip levels.

That sort of layout can lead to nasty aliasing at the seam and I'd generally advise against it - especially in production where mipping and texture compression play havok with your carefully created maps. 

In the case of the grenade body I would map it cylindrically and then fix the vertical distortion as much as possible by shifting whole rows up&down.

In a world where texturing is done with bakes and 3d paint apps it makes sense to prioritise bake quality and LOD support over maintaining square pixels. 

So is better to make a cylindrical map and than makes the edge more straighten? 

poopipe

In my opinion and experience yes. 

Thanez

Both yes and no, but in this case, I think no. In my experience, there's rarely a single correct way of doing something. A decision either nets you A or B, or somewhere in-between, but rarely both.
Poopipe's viewpoint is correct in that the further away you view this from, keeping the all the UV edges as straight as possible will preserve the edges you've baked the best. The sharper the baked edge, the more important this becomes.
For consistent texel density, the oval shape is best, but at a distance it will break down. Aliasing and visible seams at the split UV edges can be avoided 100% by not applying the detail texture in UV space, instead projecting it triplanar. 

While I argued that all the other edges should be straightened, that was because most of those edges are sharp, in 90% of cases you can get away with slightly skewed textures scot-free, and if you don't, you won't even need to mip that sucker once for it to look like a jagged mess.
On the asplody body however you have edges that are ~10 pixels wide. Even at mip 3 those should hold their own, so you won't be able to see the issues that certainly will arise from using a more oval shape. What you gain from doing the oval style map is a much more consistent texel density, and for the size of that particular part, I think that it's more important that this looks it's best up close than at 10m.

TL;DR: We're debating whether to avoid a piece of shit or a turd sandwich. OP gets to choose, and it'll be a great learning experience if he tries both.

marco_3D_artist

Thanez said:

Both yes and no, but in this case, I think no. In my experience, there's rarely a single correct way of doing something. A decision either nets you A or B, or somewhere in-between, but rarely both.
Poopipe's viewpoint is correct in that the further away you view this from, keeping the all the UV edges as straight as possible will preserve the edges you've baked the best. The sharper the baked edge, the more important this becomes.
For consistent texel density, the oval shape is best, but at a distance it will break down. Aliasing and visible seams at the split UV edges can be avoided 100% by not applying the detail texture in UV space, instead projecting it triplanar. 

While I argued that all the other edges should be straightened, that was because most of those edges are sharp, in 90% of cases you can get away with slightly skewed textures scot-free, and if you don't, you won't even need to mip that sucker once for it to look like a jagged mess.
On the asplody body however you have edges that are ~10 pixels wide. Even at mip 3 those should hold their own, so you won't be able to see the issues that certainly will arise from using a more oval shape. What you gain from doing the oval style map is a much more consistent texel density, and for the size of that particular part, I think that it's more important that this looks it's best up close than at 10m.

TL;DR: We're debating whether to avoid a piece of shit or a turd sandwich. OP gets to choose, and it'll be a great learning experience if he tries both.

Thank you! now is more clear 
In Substance Painter, I applied triplanar projection and I don't see any problem. 

Thanez

You can test mipping by viewing maps at 0,5x 0,25x and 0,125x res to see if issues pop up. It won't be 100% the same as in-engine, because their downscaling algorithm will vary, but it'll give you a ballpark idea of how well of a job you did.

marco_3D_artist

Thanez said:

You can test mipping by viewing maps at 0,5x 0,25x and 0,125x res to see if issues pop up. It won't be 100% the same as in-engine, because their downscaling algorithm will vary, but it'll give you a ballpark idea of how well of a job you did.

Ok, Thanks I'll try that