how to prevent sun from reflecting inside

i can see the sun reflection while inside

is this intended behavior?

could i set up to prevent this somehow from reflecting while im inside and surrounded by bsp?

im using the skysphere from engine content

best regards

Is this a “soft” corner or a solid corner?

Soft corners can mess with the math involved in determining where light falls.

i see your picture but i don´t understand that soft and solid corner stuff, sorry.

in the screen there is a 90 degree corner, if that matters
basically its only a square brush subtracted from a larger square brush, there are no other angles than 90 degree

the effect is everywhere inside, not only on floor, not only in corners, its also on walls depending on the looking direction

corners examples

A pair of FBX files showing the different corners.

If the corners are solid you may try exporting the BSP blocks as FBX and importing them again.

The physics brushes aren’t actually meshes so they have a few quirks of their own. They are intended for quick building with the expectation you will replace them once you have the basic idea worked out.

If neither of those ways work, if you send me a copy of the map itself, I can make the actual meshes to replace the BSP brushes and see if that fixes your problem.

(sorry it took so long to respond)

Hmm. I don’t know why it would ‘seep’ than.

Let me throw together a few meshes and upload them - maybe see if solid meshes fix the problem.


Just 3 cubes with different origins.
One that sits on the floor/ground, one that is centered, and one that sits under a plane to work as a floor.

See if putting down a “floor” and wall piece block the light seeping in.

thank for the example, i now understand what u are saying.

the corners are solid in my case then, i built it this way mostly because of the looks from outside…

i will try to convert it to static mesh, but afaik i cant convert it back to BSP after this step, so it will be impossible for me to make changes or adjustment to the geometry and materials of this, is that correct?

the specific object is a three story house, using simple geometry

is it better to convert every single brush into a mesh each or should i do the whole building to one single mesh?

thanks for your help and examples, i even tried that, but sorry i think its not something directly to do with lighting or leaking light because the scene does not get brighter or darker in relation, its only the shiny sun disk thats reflecting on the brushes materials, while it should not do when inside and surrounded by geometry…

the lighting itself from the directional light is not going inside, it seems blocked by bsp, not the reflection tho

maybe i can fix this inside the skysphere_bp or material settings of the surfaces?

This is no matter soft or hard corner, because this is no light leaking, but reflection, cubemap problem and connecting walls have any influence.


This is problem I have seen before on some UE demo Content Example, this scene with palace on ocean, same as your problem in few darker corners. And in many other games it happens too.

Back to answer, you should add Box Reflection Capture to this place. Maybe this box should cover whole room or just this corner, it need tests. Also, Box Reflection Capture settings must fits room size, because if will be bigger - default is 1000x1000x400 - it will be gather reflections from out of this room.

This can be pain anyway, but in my opinion this is worth for realistic effect. If still problem, even after adding Box Reflection Capture (or in some cases Sphere Reflection Capture) you have few emergency solutions, used a lot in game design:

  • limit reflecting surfaces
  • add ambient light to dark rooms/places
  • play some with post process effects - in short words…
  • create custom cubemap for this place - and this is best, but most costly solution in UE

Have a fun and good luck

ps. Dark places with reflections creating always problem in any known engine, please correct me - I hope.