Hey guys, i have this high poly model right here:

And a low poly

and, like everyone else does, i make a normal map from the high poly for the low poly and it happens something like this:

A couple of my problems are displaced areas, screwed-up areas and bad shadings. Do you know any tips i can use to make the normal map fit and look perfect on the low poly model?

Some of the things in here might help.
http://wiki.polycount.net/Normal_Map

Overall your map looks pretty good though, just around the eyes you have some dark spots.

Noah, it doesn’t look good at all. Basically i get those 3 types of problems...i think i know you, aren’t you one of the guys from guerrilla cg? Anyway :D , there’re those 3 types of problems i described in the first post, which give me a hard time. I also have some screenshots so you can better understand what’s goin’ on.

Displaced areas

so what happens here is that the hair line from the normal map doesn’t match the edges from the low poly model. This is not that mouch of a big problem cuz i found out about a plugin for 3dsmax called polyboost which allows me to move around those areas as if i was changing the uv, though i’m not.

Screwed-up areas

That i got no clue what’s it all about. (that’s the ear you’re looking at)

Bad shadings

Same thing, i can’t see anything causing this.

I’m also reading what you gave me but it’s really difficult to identify what sort of problems i have.

Nope, not from guerilla cg, but we could be familiar from elsewhere. Thanks for these images, they’re giving me much more info.

1) Modeling the low-poly is a series of choices in where you want to reduce the silhouette, but still retain enough vertices for definition and for animation. For the hairline you can either adjust the cage and re-bake, or you can move the lowpoly edges to match the highpoly better, or you can add more edges, or you can shift the UVs (though this can add distortion of its own).

2) The ear problems look like overlaps or ray-misses in the bake. This section has some things you can try. It would also help if you posted the normalmap itself.
http://wiki.polycount.net/Normal_Map#SolvingIntersections

3) What shader are you using? Some of the shaders that ship with Max don’t solve seams or mirroring very well. I haven’t spent time updating this section since Max 9, but it might give you some clues.
http://wiki.polycount.net/Normal_Map#ShadersAndSeams

Wow, you really know what you’re doing :D . Ok, i’ll go for bad shadings first, see if i can fix them.

[Edit]

Ok, i tried those 3 shaders but all 3 messed up the material, not to mention that none solved my bad shading problems xD . Does that mean that my normal map is broken from the beginning? Or at least it’s not a software issue?

edithegodfather 09 November 2009 10:48 AM

Does that mean that my normal map is broken from the beginning? Or at least it’s not a software issue?

Could be, hard to say. Did you bake using Max’s RTT? Did you bake with the scanline or mentalray renderer? Did you mess with the UVs after the bake? (certainly do-able, but you have to be careful) Did you adjust the low-poly model after the bake? (again, have to be careful)

Did you bake using Max’s RTT?
No, i baked it in mudbox, or at least i don’t know what you’re talkin’ about xD .

Did you bake with the scanline or mentalray renderer?
No, i don’t think so, anyway i don’t know what’s that.

Did you mess with the UVs after the bake? (certainly do-able, but you have to be careful) Did you adjust the low-poly model after the bake? (again, have to be careful)
Nope didn’t touch the mesh nor uv’s after bake.

Bake means to create the normal map, by “baking” the normals from the high-resolution mesh.

If you baked in Mudbox, then you probably will get seams in Max. The simplest way to solve the seams would be to import the highpoly mudbox mesh into Max, and bake it with Max’s Render To Texture.

Edit… moving a normalmapped mesh between apps is often problematic, sometimes because you don’t know if the apps use the same tangent basis, other times because the model format can strip out vertices or normals, or it can add new ones, or it can change the UVs subtly. All of these affect the way the normalmap is displayed. You just have to test out all the options.

Hmm :-? i’ll see how’s with baking in 3ds max. But i also used xnormal for baking and i got the same shading issues, exactly identical.

There’s a catch here, you know. When i modeled the head i did a bit of cheating, i didn’t model absolutely everything you see there. The eyes, lips, ears and the neck stomp were taken from the ut3 male model they give you on udn and the shadings occur exactly in those areas, well the eyes don’t look that bad but i think it’s not just a coincidence that only the lips and ears look bad.
I was thinking if there isn’t some sort of process to bake the head and get rid of those shades.

That usually isn’t a problem with baking, it’s problem of plagiarism. But my earlier point was that to solve these errors, you should eliminate the methods that often cause problems, like baking in one app and rendering in another. Sometimes it can work, but it can also just as easily break.

You should also make sure your low-poly model doesn’t have mesh errors like unwelded vertices, or multiple smoothing groups where you usually want just one, or overlapping polygons, or T-vertices, etc.