[Help] Weird artifacts in baking! (Xnormals)

SimãoSilva

Hi, today i tried to make an asphalt cylinder, but when i go to bake it i get this weird artifact in the normal map.

I don't know why this is happening, i think it had to do with smoothing groups but at the same time i don't think that !

Here is a picture of the models wire frame, the unwrap and the whole normal map bake!

Thank you all in advance !

Have a nice day.

Simon

Bartalon

That waviness is normal for cylindrical surfaces.  It's because you are baking a perfectly round surface down to a few polygons which have a much more angular curvature.  The solution is to increase the number of sides on your cylinder.

http://polycount.com/discussion/81154/understanding-averaged-normals-and-ray-projection-who-put-waviness-in-my-normal-map/p1

SimãoSilva

So the best way to solve this would be to make a version with more polys, bake that one and then apply that bake to the low poly one ? would that work ? sorry to ask but I'm not at my computer right now ^^

Bartalon

No, you would just use the mesh with more sides as your low poly.  Normal maps are tuned to the exact mesh for which they are baked so applying it to another model, even one using the same UV space, will not display properly. 

I should note that your goal shouldn't be to completely eliminate this waviness from your normal map.  It's not inherently bad that the waviness is there, as it's a direct result of the normal map compensating for the difference in shape of your low poly compared to the high poly.  Check the normal map applied to the low poly and see if it is satisfactory.  If it looks fine, then it doesn't matter what your normal map looks like.

SimãoSilva

tahnk you so much ! i went ahead and drew the normal maps using piece of the bad one and i fixed it ( it looks good now! ) and also tried the same but adding more polys, both ways worked out pretty good ! but i went whit the one with less polys of course

Sean_P

You could also use a high poly which is just the low poly with bevelled edges and no sub division, because the geometry is the same you won't get waviness

SimãoSilva

Never thought of that! thanks ! even though i solved it by painting it by hand that would have also worked thank you ! IL upload the finished model in a bit if you want to see !

musashidan

SimãoSilva said:

Never thought of that! thanks ! even though i solved it by painting it by hand that would have also worked thank you ! IL upload the finished model in a bit if you want to see !

Just to make you aware, painting out baking errors on your NM is very bad practice. NMs are not like other textures. The RGB data is encoded/decoded in the texture.

You might have got a result this time but it is a bad habit. You're better off learning why NMs work the way they do rather than hacking your way to results by painting.

SimãoSilva

musashidan : Thank you for the warning ! I'll keep that in mind in future work !