Norm Baking: Smoothing Groups?

olivierth

Hi,

I've modeled a low res gun so I can bake the high res onto and I was wondering if it's a good idea to change smoothing groups on some parts so it would "help" the normal map baking.

Because my low res is very low and has a few long triangles it causes some problems with the normal maps.

Thanks

Mr Digital

Can you show us any image for reference? i guess for now is just the cage.

olivierth

My question is more about non-deforming objects in general, not just my gun. I don't want to get input on how I should change the topology. I simply want to know if it's a good practice to modify the smoothing groups on a non-deforming object so it would help with baking the normal maps.

WarrenM

If you're going to be using this mesh to bake a normal map, then your smoothing groups are important and you can't just change them randomly without changing your UVs. The basic rule goes:

Anywhere there is a smoothing split, there HAS to be a UV split - or suffer the nasty edge artifacts.

https://www.youtube.com/watch?v=ciXTyOOnBZQ
(this is the best 9 minutes you'll spend today in learning about normal maps and smoothing groups)

olivierth

Thanks, good to know! It's annoying that at the end of the video he says the next video will be about how to bake using different smoothing groups but the video is not yet created. Oh well, I'll test it out.

Thanks for the help!

olivierth

I applied a projection modifier on my gun with different smoothing groups. The problem I see is none of the cage point are split at the smoothing group borders. Does that mean I should literally split my model per smoothing groups before applying the projection modifier?

Thanks.

Farfarer

You shouldn't split the cage, but if you have a smoothing split, you'll need to have a split (and a gap) in the UVs along the smoothing split.

The reverse is not true; splits in UVs don't need a split in smoothing.

olivierth

When I said "the cage" I meant the projection modifier's cage. I can't split those so I was wondering if I'm supposed to split the model into separate elements according to the smoothing groups before I apply the projection modifier.

joeriv

No, your cage isn't supposed to be split.

Farfarer

olivierth wrote: »

When I said "the cage" I meant the projection modifier's cage. I can't split those so I was wondering if I'm supposed to split the model into separate elements according to the smoothing groups before I apply the projection modifier.

Yep, I meant the projection cage, too.

You shouldn't split it or you'll end up missing bits of your high poly mesh in the bake.

olivierth

RIGHT! I didn't think about that! Sorry I didn't understand at first.

Alright, I'm good with that info.

Thanks for all your help!