Spotlight shadow-caster culling control

Development Rendering
, , , , ,
1

I have a setup with a car that has two spotlights for headlights. They’re dynamic lights.

Staticmesh objects that get in front of the car cast shadows fine so long as the camera is close to the mesh. When the camera gets further away from the static mesh, the mesh won’t cast shadows any longer. The distance the camera can get before the object stops casting depends on the size of the static mesh – larger static meshes allow a further distance. So it’s a function of object size and camera distance, but the field of view isn’t taken into account and so lower FOV (around 40) will give lots of shadow popping.

Skeletal meshes always appear to cast shadows, as far as I can tell - regardless of the scale on screen.

I’m looking hopefully for a setting where I can set the distance the camera can get from an object (or more likely the size an object can be on the screen) before its shadow disappears. The min screen radius setting in Project Settings only applies to cascaded shadows, which aren’t used for spotlights.

If there’s no setting, is this a bug? It seems to me it should take the camera FOV into account.

2

Hey kurtrussellfanclub -

Currently you have reached a limitation to the engine, but I have entered a request for our engineers to look at implementing possible solutions to this issue. I am assuming that your car is mobile and controlled in game. If it is static and not moving then you can use the new Distance Field Ray Traced Shadows to achieve the look you want with a Stationary Light, but lose the ability to move the light itself.

I will keep you informed as we investigate this issue further

Thank You

Eric Ketchum

3

Thanks so much Eric. My car is indeed mobile and controlled in the game.

I’m sure the engineers are all over the system but if it helps- I tested it with dynamic point lights and it occurs as well. It seems that the attenuation of the light isn’t taken into account at all, so it looks absolutely fine for low attenuations but for larger radius spotlights and point lights it produces popping.