Shadow Map Technology is creating dark spots on some meshes

[wevetments]

1. What issue are you having? Describe what is happening when the bug occurs. Describe what you would normally expect to occur.

I have uploaded several meshes in the past months and ever since I set Shadow Map as my lighting configuration, dark spots appeared on most of the meshes.

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2. Does the bug happen 100% of the time?

The dark spots are present on the affected meshes 100% of the time.

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3. Where does the bug happen?

Live Games and Studio

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4. Screenshot

(Source: @maplestick)

(Source: Me)

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5. When did the bug start happening? If we can tie it to a specific release that helps us figure out what we broke.

Ever since the shadow map update

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Note:
I am willing to provide the mesh files via Private Messages

[TheRings0fSaturn (SaturianNightmare)]

This happened to me after I set some meshes to be “Automatic” in their RenderFidelity property, which seems to have completely broken the shadow system for these meshes.

Places affected have a “negative shadow” as well.

[filiptibell]

This is happening in our game as well, with RenderFidelity on all meshes set to Automatic.
Also getting the same “negative shadow” in some places, like @TheRings0fSaturn mentioned.

It seems almost as if the mesh is casting a shadow onto itself? Maybe the different LOD meshes are casting shadows onto each other or something? As a temporary fix, it seems like making small changes in the mesh and reuploading can sometimes solve the problem.

[wevetments]

After further experimenting with the lighting, the only way I got the dark spots to somehow disappear was to change the Outdoor Ambient to pure white.

[nooneisback]

CSGv2 is stable outcome-wise. It almost never fails, but the results are barely satisfactory.

Here is an example of a non-union sphere-shaped part compared to what happens when you union it.

It just looks awful with many useless faces and senseless normals which often cause shadow issues.

Here is a union structure I made in Roblox and its remake in Blender with the boolean modifier and then triangulated with the fastest method (couldn’t directly use the output of “Export as .obj” as the individual parts are separated into multiple meshes representing individual sides).

The triangle count is almost by a quarter smaller, the result has perfect normals and the edges are also much cleaner. Also CSGv1 and v2 treat touching faces as something that shouldn’t be joined.

Just a note: I made sure that the UV-Spheres have a triangle count as close as possible to the Roblox’s spheres.

[zeuxcg]

Just a note that the shadowmap issues are unrelated to the CSG algorithm etc. - they are the artifact of us not handling level of detail cleanly. There’s a fix for this that will ship in the next few weeks.

[nooneisback]

Importing from another topic:

The bug report already exists.
What I’m saying is that those mushed up faces tend to make this issue even more noticeable as you can clearly see the irregularities. This is only an issue with shadow maps.

The CSG method itself is excellent. The issue comes from conversion between parts and unions.

Or at least they look like the same issue

This is a random part with a sphere taken out of it.