Normal map seam issue

This isn’t that big of an issue but obviously would like it resolved. I’ve tried multiple seams with same result, just varying in strength of distortion. Also tried searching for an answer with no luck, sorry if this is a common question, not quite sure how to word this issue.More interested in what causes this to happen, because its not all seams. What is the issue with those particular seams and how can i avoid this happening in the future?

BARock.blend (5.23 MB)

Not sure why there’s 2 images, cant figure out how to delete the second one.


Well, to be honest: I really do not get, what You want to get out of what you are doing here.

You have a low-poly mesh, with some slight sort of smothing. Then you take a normal map out of it. For what purpose?

Maybe you are not really aware of the use/informations that normal-maps are porting.

“In normal mapping, the information relevant to illumination about the alignment of the Normals is transferred from a high-resolution to a low-resolution 3D model. The detail of the surface is thus optically preserved. The low detail is only visible on the silhouette, which still corresponds to the low-resolution model.”

So in short terms: Lightning and shaddow informations are taken out of it. And the varibility of the result depends deeply on the lightning of the scene. One lamp would give another outcome than many lamps from different locations.

For me Your issue is not an issue that comes out of seeming - it comes out of the fact that the edges, regardless, whether they are marked as seems or not, will always pass the same info. The mesh You present - in my opinion - would be the “target of a normal-map, that was done on another mesh, with high-poly-counts and in depth structure.”

Ok, but finally it’s only a guess, cause you are describing an “issue”, that does not exist, as far as we do not know what you have in mind.

Before you go getting all worked up over odd stuff in a normal map, try it out in a shader. Normal information has to work with geometry normals and sometimes what looks funny is exactly what it’s supposed to be.

These are not seams. This color change is due to rotation of uv islands in uv editor. To check for seems use shader as sirmaxim wrote.

Not quite sure what your trying to say here. The issue is that I’ve done this before a few times but didn’t encounter the visible lines when having the normal map active. Doesn’t look correct to me, but I’m not exactly a professional blender user either. Thanks for your input.

Yeah you’re right, they seem to disappear when with a shader. Although now i have defects where there aren’t seams… Is this just a lack of geometry or am i missing something else? I’ve gone back to previous projects where I’ve done this exact process to trace my steps but I’m not seeing the issue here unfortunately. Thank you for the help.

One thing that contributes is severely non-planar polygons

original on the left, nearly planar faces on the right

Triangulate modifier on top of that helps to keep the automatic triangulation from changing the geometry after it was baked.

Shadow terminator problem could also be a factor, as it often is with low poly surfaces and Cycles.

Your non-planer explanation was eye opening. Clearly a solution to my issue but I’m curious, besides going around each object that has non-planer defects and fixing them(Would you just adjust the vertices or completely flatten the face?), is there a way to avoid them from the start? Post retopology would be ideal i would think. Trying to avoid them during retopology sounds like a difficult job if using snapping. But I see you used a “cage”, i tried to find a “cage uv’s for dummies” type article with no luck earlier thinking that might help. The BlenderDocs on it wasn’t very enlightening. As usual JA12, thank you for the assistance.

Mesh menu -> clean up -> make planar faces and increasing iterations can help. On the other hand, triangulating the whole thing also makes planar faces since triangles are flat. A quad has two triangulation options and if the order changes between the bake and use, the normals aren’t valid anymore. Triangulation before baking is recommended if the model is exported to another program.

Baking cage is just a bloated version of the low poly object. Duplicate, edit mode, alt+S. It helps to solve intersection problems with a bake and no need to guess the ray distance value.

Perfect, as it stands my problem has been resolved! The non-planer faces info is gonna come in handy. Ahh, okay, think I’m good in that area. well on this rock anyway. Thanks again JA12!