Light build creates dark or black spots on geometry thats too close i assume

I don’t see any outwards pointing normals on bottom corners and near bottom of the wooden panels in the first screen. Most likely black spots occur at that side of the wall.
If the long wooden plank is tesselated, then it also doesn’t have correct normals.

Something like that could’ve happened if you created backfacing part of the mesh by duplicating and dragging front-facing portion.

When you look at the surface, surface normals should be pointing towards you. When you look at the surface from behind the surface, the normal should be pointing away from you.

Anyway, recalculate normals properly, reexport geometry and try again.

You may be onto something. i exported that model out of unreal and into my 3d package and i saw the normals were opposite direction for that side of the wall. Very strange. That model was made in unreal because i combined a bunch of assets… (the wall usually comes in a 1 sided peice and i duplicated and scaled it negative one to make it double sided… then i merged them with unreals merge mesh tool. Looks like scaling things negative in unreal is never a good idea even if it looks correct normal wise from a visual standpoint.

Still though that doesnt exactly explain foliage / rocks in terrain turning black… worst part of the rocks is its random… for instance lod 0 may be fun but lod1 turns black… or opposite can be true… or nothing turns black…

This is a little off topic, but i figure id ask. Whats the best approach to lighting a 2 sided flat peice of geometry that light can somewhat shine through like sss … almost like foliage… like paper shoji windows or something…?

It does explain it. Lighting is calculated based on normal and direction towards light source (n dot l in traditional shaders). If normal points towards light, surface is lit, if it is pointing away, surface is in shadow. Normal is interpolated across faces for the purposes of light calculates.

If normal is flipped to the opposite, you get black surface. Black plant most likely has normal flipped. Rocks are lacking proper edges, and normals are either overly smoothed or pointing in the wrong direction, which would produce similar effect - black spots.

Basically, you have an issue related to either smoothing groups or normal export somewhere. Cursory look at your level in the first screen show that there’s quite a lot of geometry that appears to be smooth shaded, although it looks like it is supposed to have hard edges.

For example, column near that gate at the first screen seems to be smooth shaded. Half of the pillar on the same column also looks smooth shaded. There’s strangely smoothed ends of steps on stairs, etc.

Thats intentional. Some of those are actual props where the normal map is generated from a high res model. So how would u do something that has to be lit from 2 sides and is flat? Like shoji windows.

There was “two-sided-lighting” checkbox somewhere.

https://wiki.unrealengine/LightingTroubleshootingGuide#Two-Sided_Lighting_for_Single_Sided_Meshes.2C_or_Why_does_my_light_come_through_the_roof.3F

THat never works out nice after a lightmap bake. I mean with realtime lights it works great, but 2 sided lighting in a lightmap bake makes one of the sides dark always… Its as though it does take some lighting from the other side, but its much much darker…

See the screenshot for what im talking about… Baking that should not make it practically black in a lit room…

I’m not dealing with this kind of levels, so I can’t help with that.

You could try turning those into high-opacity translucent windows, or just cheat and add emissive glow to the “inside” surface. Aside from that, I don’t have any ideas.

I dont know if thos helps but i switched my lights to movable and it fixed this problem for me its a cheap fix but it works

Your nice work looks like you have big experience with meshing and setup.
Happens that only to your meshes? Basic UE4 assets behavior different?

Have you more then two uv channels on your objects? First channel UV- second LM?
I dunno if that helps, but i encountered something a bit similar some time ago.
The meshes i imported into UE with triangles in the basemesh (not quads only, before triangulating) caused(cause) problems sometimes.

When i make clean quadtopo and export that, i get no errors.(Blender)
Overlapping/loose faces/vertices/hidden objects?

What is when you make a cube and or sphere with emissive material and place it in your darkish scene?

Edit again: mhhh when i look at first picture https://forums.unrealengine/showthread.php?88850-Light-build-creates-dark-or-black-spots-on-geometry-thats-too-close-i-assume&p=406671&viewfull=1#post406671
Can you make a shindle one seperate object with own uvmap lightmap, and then try it again? Your whole object is onto one lightmap…
Scaled you the models down so much inside ue4?