LOD Baking in Marmoset?

Geosmith

Hello.

With the new addition of baking PBR textures from a highpoly I thought I'd give LOD creation a go by baking down my lowpoly mesh onto a completely separate LOD1 made from scratch and unwrapped with unique UVs. 

For the most part, it works really well. The only issues I really see are with the normal map baking. It seems all details instead of for example going upwards are going inwards and any hard edges or UV seams appear super ugly. It also seems the smoothing from LOD0 is bleeding through into the bake. 

I've been flipping channels like hell, both in the materials of LOD1 and LOD0 as well as in the baker settings. No combination that I've found seems to do the trick. Other combos just look much worse. Hoping I'm missing some magic step, or is this not supported? Maybe it's a broken feature? Thanks.

EarthQuake

One thing to do would be make sure your tangent space is locked down throughout. So make sure you're using the same tangent space when you bake the LOD0 normal map, make sure your LOD0 source mesh is set to that tangent space, and make sure the LOD1 target has the same tangent space as well. If there is any sort of tangent space mismatch it will bake into the end result.

The hard edges problem is unexpected but could be related to tangent mismatching as well.

Geosmith

@EarthQuake

Tangent space is definitely the same wherever I have the option to set it. 

EarthQuake

Okay and the original source normal map, was that baked with Mikktspace as well?

Geosmith

Yeah, baked in the same scene, just duplicated the baker. Tangent space was never touched and remains mikktspace everywhere. Double checked and rebaked all normal maps.
I even made a completely fresh scene. Here you can see three different meshes. Far right is lowpoly in the original highpoly to lowpoly baker, in the middle is the exact same lowpoly used to bake to LOD1 with the same normal map applied. Far left is LOD1 baked from the middle mesh. There's only two bakers and both have Mikktspace, all the objects in the bakers are automatically assigned mikktspace from the baker. Made sure not to ever flip Y channel either in this new scene. Same results.

EarthQuake

Okay cool thanks, if you can send us this scene we'll take a look at it. Please package up the low/high poly meshes files and the .tbscene and send it to support@marmoset.co with a brief description of the problem. Thanks!

DRoss3d

For these types of LODs I usually just get the normal information directly from the high poly. The only downside is that you need a separate scene for the other maps (albedo, gloss, etc..)  and you will have to deal with the name matching. 

Geosmith

Not viable when you need to add a lot normal info through painting. Patterns and some effects are often faster achieved through texturing, which can take up pretty big chunks of an asset. Even subtle bumps will mess with how lighting hits the object which even if subtle will add to how noticeable a pop-in is. Highpoly would work fine in some cases like this one but hopefully this issue is resolved for future use. 

DRoss3d

Very true, I haven't ran into that situation (yet), so baking from the high poly is usually the most viable option for me.