Spotlight question

[andy_smith]

I’ve been struggling with spotlights this past few days:

1. In the room I’m in now at home, I have a spotlight. I can see the bulb (too bright to look at) as well as a glow around the bulb and then light illuminating the surfaces it is hitting.
2. In V-Ray, I can only see light on the surfaces it is hitting: there is no bulb illumination so the ceiling is pitch black even though, in reality, you’d see a bulb there and some amount of halo around it.

Is point 2 above how you’d expect V-Ray to behave? I.E. it’s almost as if it’s saying “this spotlight ONLY renders the light that is reflected off other objects in the scene; it does not emit light from its source so you cannot see it”. It’s kind of behaving like infrared hitting a target that is phosphorescent: the source is invisible to the camera/eye but the absorbed/reflected rays are visible.

I’ve looked at the training materials (although I can’t find anything for V-Ray 5 that shows the answer to this and have searched on the forum too. I’m starting to wonder if all the other folks out there who have rendered great scenes with spotlights glowing brightly in their ceilings have just resorted to throwing “fake” emissive materials in there or even pasted coronae in PP using Photoshop...

thanks!

[georgi.georgiev]

Hi andy_smith

In respect to real-life spotlights, the effect is produced from the diffuser surrounding the bulb. Remove that an you have a sphere or omni light which emits in all direction.

In V-Ray, spotlights are essentially a point in space which emit light in the direction specified by the cone and penumbra angle. In most cases, they are used inside a body of some sort (be it pendant, sconce or similar light fixtures).
If a physical source is necessary, as you have mention, faking it with a sphere or mesh light and adjusting how they affect the scene (Options rollout). Note that the source of the spotlight needs to be on the outer side of any geometry and cannot be overlapping with any surfaces to produce visible light.