Baking Errors
Hey everyone, I just recently completed a tutorial for making game ready models. This meant that i would have to bake a normal map, while i follow the tutorial to the letter i still came upon some baking errors. Any help in resolving this would be greatly appreciated! Ps. The image on the left side is that of the bake and the error is this strange line down the model.
Replies
edit: I did try the different coordinates flips before i had changed the tangent. Didn't try it after the tangent which was a new guy mistake i suppose XD.
Don't confuse the purpose of the maps. Normal map will always be on its own (maybe with a specular in its alpha channel), but AO and cavity maps either are used on themselves to occlude global illumination or are multiplied on top of the diffuse map to simulate GI.
To be honest, you can skip out on the cavity map if you wanted to, particularly if you don't have any smaller details the AO might have glanced over. Before you do that, make sure everything's working and fine, then go make the diffuse!
If I were you, clean up the UV's a bit. They're a mess right now.
I would advise not getting in the habit of fixing your normal map problems inside of Photoshop. You should really try and figure out the real reason behind it. It's just a bad habit to get into and a hack. It also won't produce as good of results if you actually fix the underlying problem and get a good bake the right way.
Earthquake has 2 threads that explain quite a bit about normals and baking. I'd invite you to check them out if you haven't already.
http://www.polycount.com/forum/showthread.php?t=107196
http://www.polycount.com/forum/showthread.php?t=81154
These errors happen when you bake your normal map with your triangle orientation in one direction, and then display your model with the triangles going in other directions.
To fix this, always remember to force your model to be triangulated before you bake and import into a 3D package. Before you bake, add a "Turn to poly" modifier on your 3D object and choose the 'limit polygon' option to 3. This is a non destructive way to bake and export your 3D model with 'forced' triangulation. This will fix many of your issues.
Rarely if ever fix bake errors in photoshop, in a production environment it's a waste of time.
+1000
Yeah, I think if you simple triangulate your mesh before exporting you should fix these issues. The problem is that when quads are imported into Toolbag, Toolbag needs to decide which direction to triangulate in, and that may vary from your 3d app. With max you shouldn't need to triangulate before baking, but certainty before exporting for best results.
Tangent space maps are pretty much industry standard, support for object space maps is very slim in game engines. With object space maps you can't mirror (unless you have a special shader), its much harder to add hand-painted detail, and there are issues with animation as well (again your shader needs to be set up to allow animations).
So stick with tangent unless your programmers/technical artists on your project tell you to use object space.
The differences are much larger than the swizzle/handness/green channel orientation. Max, Maya and xnormal(mikktspace) all calculate bi-normals and tangents differently, which means that if you bake a normal map in max, and send it to an engine calibrated for maya style maps, you'll likely get smoothing errors.
You should always bake in the app that your engine's tangent space is set up to use, if you're not sure, talk to your programmers.
You can also use handplane to transfer from object space maps to the tangent space of your choice for various engine.
Some engines use their own proprietary tangent space (like UE3/UDK, source, etc), and the best way to get accurate results is to use handplane.
Edit: I did give both normal post by Earthquake a read which is where i began to do the uvmap hard-edge splits but i may have messed up along the way, may need to give it another shot.
It looks like you have some other errors here too, that green decal with the wings should not be green, make sure the highpoly source mesh does not have inverted faces.
And another bit a little lower on the map has strange screen-door like artifacts. Not sure what would cause that, duplicated polys in the lowpoly maybe?
Edit: I did triangulated the mesh aswell