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Is Lightmass broken in 4.13?

I have a simple level (third person demo, except I re-built the floor/walls using BSP blocks)
The sun and skylight are the same as in the original level, with sun intensity pulled down from 10 to 2.75.
There are a few additional point lights with small radii, marked “do not cast shadow.”
These lights are one red, and three yellow (for the pick-ups on top of the blocks on the right in these images.)

The problem is that “static” or “stationary” lights do not cast shadows onto the ground, even though they do cast shadows on the walls.
If everything is fully dynamic, shadows are correct, but there is instead a weird cyan lighting at glancing angles on the blocks.
After each change of the directional and skylight, I re-bake lighting at the Production level.
See the screen shots below:

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Additionally, the floor had a light map resolution of 1024.
When I change it to 256 or 512, a few blobby shadows show up on the ground in Stationary mode.
However, the registration of those shadow blobs is really bad; much worse than I’d expect for a 512 resolution.
The far wall doesn’t cast a shadow at all, and the blocks on the floor don’t cast shadows; meanwhile, the area in front of the ramp that came with the third-person template is way over-shaded.
This is with stationary lights. When I use static lights, even with 512 resolution, there are no shadows on the ground.
With 256 resolution, some shadows start showing up on the ground from the walls, but not from the blocks, and the shadows are weaker on the floor than on the walls.

Btw:
Unreal Engine 4.13.0
Windows 10 Anniversary Edition
NVIDIA GeForce GTX 970M with driver 372.70.

Try adjusting the lightmap resolution lower. Reference thebsp section here.

Thanks! So the problem was that BSPs get coarser shadows the higher the resolution, but static meshes get finer shadows the higher the resolution.
That’s … probably drive by some accident of history that I’m sure made perfect sense at the time :slight_smile:

I still need to understand where the cyan flashes in the dynamic lighting case come from, though.

Not sure. I’ve never put resolutions that high into bsp before. I’ll try it tomorrow when I’m back in the office though.

The higher value you use on BSP, the lower the quality. Opposite to static meshes. That’s actually in the docs. Beats me why it’s inconsistent, but that’s what it is :confused:

It’s odd, I have shadows in my project - everything casts static shadows, movable or static.

The problem is definitely the floor bsp lightmap res of 512. Default is 32. try 4 or 2 instead. The lower the better like motorsep said.

Yes, and the stupid thing is I was confused by the same BSP-vs-static resolution thing two years ago :-/
Maybe this time it will stick.

I think the cyan flashes are something else, having to do with reflection capture or something. It only happens with fully dynamic light/shadows, so resolution shouldn’t affect it.