Intersecting Static Mesh Lighting Errors.

Hi there!

The crux of my problem is that the bottom-most static mesh in a blueprint comprised of multiple static mesh lights much darker, and often of a different colour than the rest of the blueprint. We use blueprints to combine multiple parts of buildings together to generate many different types of buildings with the same mesh pieces. Static Meshes individually work fine, lightmap uvs are fine, etc.

It’s not related to being a part of a blueprint, because just stacking the building meshes will result in the same problem, and it occurs almost 100% of the time when meshes are intersecting. Moving them around the scene away from other meshes clears up the problem. Is there something I’m missing in terms of meshes intersecting causing dark static lighting?

For further clarification, it does occur whether or not the light is baked, the result is a darker value regardless, though it is much more dramatic in the preview. It’s a problem because it causes black shadows and inconsistencies in the scene. And it does occur on every set of these building meshes, but only on the bottom most section, regardless of the mesh.

Here’s the static mesh settings inside of the blueprint.

Thanks very much!

This is still an issue, and I haven’t had any responses. Any help would be appreciated.

Hi

I have been testing this issue for you and have not been getting the same behavior that your are describing. So to break this issue up a little bit, the black shadows are expected on a static build unless you have a sky light in your level to fill in the shadows with some amount of color. So adding that light into your level and adjust the intensity and color to match your needs will help with the black shadows.

The overlapping / interesting mesh, causing odd shadows as your picture above is the particular issue which I cannot immediately reproduce. If possible could you upload a small sample project to the Answerhub with just two test assets which demonstrate the same light build error you are experiencing? If you need to keep this private please feel free to send the assets via the Forums Private Message System.

Thank You

Ketchum

Hi

Thank you for your patience. I was finally able to open your level and after some digging around it looks like the blackness that you are seeing is a result of the lower hemisphere settings in the skylight. Unchecking this option should see your meshes be lit more like you are expecting in this particular map. In particular this has to do with what the indirect lighting is reflecting off of when it lights your scene. With the Lower Hemisphere set to black , then the bottom of meshes like the store front sign is rendering black and when light bounces off it, very little light is being bounced around off those surfaces. With Lower Hemisphere is Black turned off, then you are applying the global skylight to those areas as well and more photons are being bounced and calculated off those surfaces.

Let me know if I can explain further -

Ketchum