Hi,
I am getting dark spots at the UV seams of my meshes in the baked lightmap.
It looks like bleeding, but the margins between the UV islands are a few texels, so it should not be the case (?). The size of the spots shrinks when increasing the lightmap resolution, but it is already quite high and I think there is another issue here. When generating the lightmap UVs, I get the same problem, but at the generated seams. Edge stitching is activated in the lightmap parameters and the meshes have “stitch seams” activated. Also I find odd that the darkness is not justified by either side of the seam. Where do these shadows come from? The light source does not seem to matter (the effect occurs for ambient and directional lights).
I tried tweaking any setting I could find, but to no avail.
Do I need to increase the margins between the UV islands (I find them quite big already)?
Do I need to crank up the lightmap resolution until the issue disappears?
Is there something I overlooked that can fix this?
I am using Unity 2019.3.0f1 with the Universal render pipeline. I get this effect with both, the GPU and the CPU (progressive) lightmapper.
Thank you for your input!
I have the same issue, can’r believe you got no answer after all this time. Did you manage to resolve it?
If you have a proper lightmap UV generated, So the problem is the lightmap resolution
By increasing the lightmap resolution your problem should be solved
Also if you have black spot problem in the double sided faces (for example leaf), you can create a new lightmap parameters and set the Backface Tolerance to the 0.7
or select your material and enable Double Sided Glob al Illumination for your double sided faces
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Actually you need to disable filtering then bump up samples until you get a clean bake.
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This is such an old post that I really can’t say much about what happened back then and how I resolved it. The reason I didn’t just crank up the resolution is that the seams looked darker than both sides, so it really doesn’t seem like a resolution problem. What I think is happening is that the dark, unbaked parts of the lightmap outside the UV islands bleed into the visible areas through filtering. So the suggestion to disable it makes a lot of sense.
I also tried out custom lightmap bakers from the asset store, but I can’t remember the results.
Nowadays I am using the built-in GPU lightmapper with filtering on auto and I haven’t seen any of these Frankenstein Monster scars in a while.
