The Perfect UV mapping for a normal map ( Maya 2018 ) ?

Nanashi

Hi guys, I'm modeling a rifle and I'm done with the high and the low poly and now I'm doing the UV mapping for it and I'm wondering is there any rules or to put it better do or don't  when doing the UV for a normal map ? some people say its better to have a straight edge UV and that will work better  for the normal map, is that true ?  

Andreicus

Nanashi said:

Hi guys, I'm modeling a rifle and I'm done with the high and the low poly and now I'm doing the UV mapping for it and I'm wondering is there any rules or to put it better do or don't  when doing the UV for a normal map ? some people say its better to have a straight edge UV and that will work better  for the normal map, is that true ?  

Yes it's true because if you don't have straight UV edges you will get visible aliasing after the bake and even if you don't bake anything but you still use a Material ID workflow you will get aliasing when one material ends and the other one begins.
This is especially true for hard surface models.

You can also see the aliasing in the uv map, try zooming in a curved uv island and you will see that the borders are all "zig-zagged" like aliasing.

If you use Substance Painter you can put a blur filter on the material layer with aliasing to mask out the artifacts but it's not always possible and you will lose details.

Nanashi

Andreicus said:

Nanashi said:

Hi guys, I'm modeling a rifle and I'm done with the high and the low poly and now I'm doing the UV mapping for it and I'm wondering is there any rules or to put it better do or don't  when doing the UV for a normal map ? some people say its better to have a straight edge UV and that will work better  for the normal map, is that true ?  

Yes it's true because if you don't have straight UV edges you will get visible aliasing after the bake and even if you don't bake anything but you still use a Material ID workflow you will get aliasing when one material ends and the other one begins.
This is especially true for hard surface models.

You can also see the aliasing in the uv map, try zooming in a curved uv island and you will see that the borders are all "zig-zagged" like aliasing.

If you use Substance Painter you can put a blur filter on the material layer with aliasing to mask out the artifacts but it's not always possible and you will lose details.

thanks for your reply and clearing this to me. i was always told to have a clean and nice UV so the texture will be nice but when i make the UV straight it gives me a distortion, is that distortion ok ? or it will effect my textures ? is it worth it to make it straight for the normal map  on the expense of the UV being distorted ??  and how that will affect my textures ?

Clean UV but not straight


 
straight  UV with distortion


what do you think ?? 

ActionDawg

the former image is what you want in this case. straightening uv edges mostly applies to things that are long and straight-ish already and for straightening out cylindrical forms, but comes at the cost of uneven texel density and bad skew like you see in your 2nd images 3d view. so not always desired.

what you want to do with the kind of shapes you have there is how everything in pic1 looks. even, correctly rotated uv islands so as to align with the pixel grid and as "relaxed" as possible (even texel density). sometimes there are manual adjustments you want to make as well in the name of better quality bakes, giving more focus to important areas or straightening out thin edges to be pixel aligned. so it's often a tradeoff of texel density vs pixel alignment vs skew that you tinker with for the best results.

Andreicus

somedoggy said:

the former image is what you want in this case. straightening uv edges mostly applies to things that are long and straight-ish already and for straightening out cylindrical forms, but comes at the cost of uneven texel density and bad skew like you see in your 2nd images 3d view. so not always desired.

what you want to do with the kind of shapes you have there is how everything in pic1 looks. even, correctly rotated uv islands so as to align with the pixel grid and as "relaxed" as possible (even texel density). sometimes there are manual adjustments you want to make as well in the name of better quality bakes, giving more focus to important areas or straightening out thin edges to be pixel aligned. so it's often a tradeoff of texel density vs pixel alignment vs skew that you tinker with for the best results.

This ^