Normal Map aritfacts (unwanted windmill) (using cage)

TheAnosmic

Still new to this, I'm trying to bake in a simple scenario:
this is an X carved in my high poly mesh, and I'm getting these "wings" outside of it in my bakes.
I'm guessing the model is not perfect, but I tried making all the faces around the X flat, and i couldn't find a better way to model it.
(maybe I just need to find a way to do this with quads? I wraped my head around it, but couldn't find a good way to do it).
you can download the complete blend file from the low poly model.

Thanks!


model
model

jaker3278

Are you tubosmoothing (not sure what the blender term is i think its subdivision surface) your high poly model?  Because if you aren't then you are defeating the purpose of a normal map. Also the lip that you have around the cross on your highpoly i think, Will not show in the normal map as the rays that are being cast will not capture that angle. This detail should be in your low poly. As for the windmill effect your getting, it looks like you have lots of long thin triangles in your high poly try to get rid of those. And weld all verts in that area could be a floating vert im not sure other people might know exactly. 

throttlekitty

Required reading!  http://polycount.com/discussion/107196/youre-making-me-hard-making-sense-of-hard-edges-uvs-normal-maps-and-vertex-counts

The basic rule is that you should have hard edges where the geo is around 90 degrees or greater, and also split the UV's into islands along those edges. I'd also suggest removing all the internal edges along that bevel for a low poly model like this, the normal map will cover that for you.

lotet

was just about to link the same thing @throttlekitty but I wasnt quick enough apparently =P
It really is a must read!

Basicly Mesh normals and UV seams/layout is super important to good normal maps.

Obscura

The "windmill" thingy is visible in your normalmap, because its also visible on your not so highpoly highpoly mesh. Its coming from the vertex shading of that. If you rotate the mesh around a little bit, you'll see it.  Add more geometry to the highpoly.

jaker3278

If i were you i would test out baking normal maps on a really simple object ( say a cube) , read the link that throttlekitty provided and bake until you know the fundamentals and have it right. then move on to more complex shapes. Otherwise you might get confused if you try to apply it to the geo you have in your example. 

Joopson

Obscura said:

The "windmill" thingy is visible in your normalmap, because its also visible on your not so highpoly highpoly mesh. Its coming from the vertex shading of that. If you rotate the mesh around a little bit, you'll see it.  Add more geometry to the highpoly.

Yeah, Obscura is absolutely right here. This isn't a baking issue, in this case (but still read those links shared above anyway! They'll make your work better and save you a million headaches.), but a problem with the high-poly mesh.

daniellooartist

You could probably make the top and the sides of the high poly 2 separate pieces instead of trying to make one topological collision. Let us know how it ends.