Some noob questions about normals (again)

nefarius

Hello all! Now i'm modelling the M320 Grenade launcher and i' ve almost finished with hipoly model and lowpoly model and now i'm preparing to make UVs. And before doing that i need some clarification in a couple of questions.

1. How to deal with normal maps? If i'm right then i need to:
| make different smoothing groups for different islands on UV
| then bake normals from hipoly and use tangent space normals in my final model or can i use object space normals? (model is not deformable, all moving parts are solid hardsurfaces)
| if i use tangent space normals, i must have pretty clean geometry on cylindrical and other smooth parts, yes?
| if i use object space normals so how can i export them right from the Substance pinter and apply to the model in Marmoset with any additional detalization that was created in Substance (many Substance materials use normal map channel)

OR

should i use one smoothing group wor the whole model and use object  space normals for the final result?

If i am wrong at something please correct me. I really want to know what to do before start doing something ) Now i have few unwrapped parts of the model and try to experiment with different settings/options.

I am using Substance Painter for baking textures.

Axi5

Test your ideas on some simple models. Learning by doing is the best way to learn. You're in the right mindset, just try some very simple geometry with some test cases similar to your model and see what happens.

nefarius

Axi5 said:

Test your ideas on some simple models. Learning by doing is the best way to learn. You're in the right mindset, just try some very simple geometry with some test cases similar to your model and see what happens.

I am trying ) And now it looks like object space normals much more easy to create and use and i don't have to care about smoothing groups. And maybe i don't understand something, but all weapon models that i see on Artstation have object space normals.
I just need to know which way is right if i try to create game model.

pior

No - the viewer merely shows you the processed, object space normals. That doesn't mean that the artist used object space normals to create the asset itself.

nefarius

pior said:

No - the viewer merely shows you the processed, object space normals. That doesn't mean that the artist used object space normals to create the asset itself.

Thanks! So i am right here, yes?

nefarius said:

| make different smoothing groups for different islands on UV

ActionDawg

No, other way around. You make different UV islands for different smoothing groups. This is because where smoothing groups get split, if you don't also split the UVs in the location where your normals split you will have an infinitesimal line where the baked normals would need to transition from one value to the other.

On the other hand if you split normals exactly how UVs are split you can actually wind up with worse results. Consider that a cylinder must have a seam going down it to be feasibly unwrapped. If you were to split your normals along that seam as well, the normal map would have to work harder to correct for the split.

nefarius

somedoggy said:

No, other way around. You make different UV islands for different smoothing groups. This is because where smoothing groups get split, if you don't also split the UVs in the location where your normals split you will have an infinitesimal line where the baked normals would need to transition from one value to the other.

On the other hand if you split normals exactly how UVs are split you can actually wind up with worse results. Consider that a cylinder must have a seam going down it to be feasibly unwrapped. If you were to split your normals along that seam as well, the normal map would have to work harder to correct for the split.

Thanks man, it's that i mentioned. Now i am trying to do that:)