VRay: Mesh light doesnt work with Surface in front of it

I have a problem trying to get a shape of the light on my floor. I modelled lamp like this.

and made holes in the surface to let the light source inside emit the light through.

However the render turns out like this.

where I would like to achieve effect similar to this (phoshopped version)

here’s a closer look to the lamp head with annotation

and a snapshot of the scene

I’m using V-Ray 3.40.01 for Rhinoceros 5 SR14.

I tried a test with a sphere with holes and mesh sphere on the inside (and made it vray mesh light). When I placed it really close to the target surface (floor) it worked. It shines the light through the holes. But that is way too close for a lamp. example here:

I hope the images explain everything well. Here’s the .3dm file just in case.


Hi @swenreindl

That’s the physics of light - not a rendering issue. Build a mock-up or scale model, and you’ll see! If you want the light to hit the ground as focused dots, you are probably going to need both a reflector and a lens to get it focused - basically you want to force the light to travel (close to) parallel, and light tends to spread out - especially if the light source is a light emitting plane/surface, which is what I think you have here. Take a look at stage lighting/follow spots and high powered torches for examples of how it can be done. For you rendering needs, you are probably better off using a single spotlight for each hole and adjusting the hotspot of the spotlight to fit the size of the hole. I have a feeling that getting the reflector and lens right might be quite the task if you are not an engineer with lighting experience and the render times would probably be looooong :grimacing:

HTH, Jakob