noob question--normal map seam baking from 3ds max

zuno

Hi guys,
I try to pack my UV more efficient, so I break the rim to two pieces, and the result is I got ugly seam on the model.
is it better not breaking the rim or is my bake setting is off? 
Got this model all in the same smoothing group.

Thanks,

Eric Chadwick

Depends on how the normal map is rendered. If this is viewport display in Max, there's likely going to be seams, because Max's viewport rendering generally sucks.

There are several ways to display normal maps in Max, I can't remember which ones are synched to their baker, the only one I remember for sure is to use the Normal Bump map type in a Standard material and render with the Scanline renderer.

Usually the most important thing is to check how your eventual game engine is rendering your normal maps. Most are not synched with 3ds Max's baker, if I recall correctly.

Revel

Half cylinder of the rim is arrange horizontal and half is vertical it's gonna give seam on normal map no matter what though. It's better to arrange it on the same direction/ orientation.

huffer

These seams are because of gamma mismatch, try loading your normal map file in the material editor file with Gamma 1.0 (choose override when you load the rendered file); or just disable gamma 2.2 in the Gamma / LUT setup (set it to 1.0).

poopipe

max2015  (and later?) can use Maya's tangent basis which is a pretty safe bet for testing as it's closer to most engines than max's native one.

The realistic material display in  nitrous and scanline baker appear to be synched to whatever tangent basis you choose in the max preferences.

If you lay those UVs out straight across the texture page you can tile them and save even more space. 

zuno

thanks for the reply guys,
I bake using 3dsmax "bake to texture" and load up in both max and unity with proper setups, they all have seams. using max 2015
@Revel : shouldn't the bake correcting the direction/ orientation when baking?

Revel

Yeah that what I thought at first too but apparently it's not, even view in UE4 eventhough it's barely visible..

When you bake normal based on UV ch1, but your UV ch2 arranged on different direction, it still showing slightly different normal direction there. I have no idea the technical issue behind this..

Your screenshot looks too extreme to be caused by this though, like huffer said, did you check the gamma?

zuno

I load it in the Marmoset Toolbag, got the same seam. so must be the baking issue. just trying to find what cause the seam. I tried assign different smoothing group for different uv island. same. 
the reason I break the uv like this is because I want to have better texture density. Or it's just no other way around, must have UV in one piece to have a clean bake and sacrifice texture density?