Omni Light oddities

[thomthom]

I'm working on an interior - something which is pretty new to me, it's not often we do that at the office here.

I added a couple of spot lights (omni-lights) under the bookshelf on the right hand side:


From a floor level the intensity looks like this.

But when I render and top-down view of it I get an intense burn:


There is no change between the two renders other than the camera perspective.

Anyone got some pointers to why this occurs?

[Jackson_cg]

Re: Omni Light oddities

I think the likely culprit is the invisible ceiling in the bird's eye view- the combined intensity of the lighting from GI and Omnis are probably causing the burn. You could reduce the multiplier on the omnis, or maybe try saving it out as .hdr and adjusting the tone mapping in an HDR editor to remove the burn.

[thomthom]

Re: Omni Light oddities

But the ceiling is the same in both renders. One side is solid the other transparent - so you can see into the room. That way the sun didn't enter the room other than from the windows.

[Jackson_cg]

Re: Omni Light oddities

Hmmm :-\ ... what are the focal lengths in the two images?

[thomthom]

Re: Omni Light oddities

From inside the room: 40mm
Top-down: 57mm

[thomthom]

Re: Omni Light oddities

Just to show a third view - up close of the omni-lights.


Same X-Ray ceiling as the previous two. Focal Length: 40mm

[Jackson_cg]

Re: Omni Light oddities

I've no idea what the problem is then- must be a 2 sided material bug affecting how omnis are viewed from the other side?

[thomthom]

Re: Omni Light oddities

hm.. I'll do some further tests tomorrow.

[nomeradona_cg]

Re: Omni Light oddities

my guess is that they are the reflection from the wood material. you have to uncheck affect specular on your omni lights. on the top view you can see the reflection parallel to the viewing angle..

[thomthom]

Re: Omni Light oddities

my guess is that they are the reflection from the wood material. you have to uncheck affect specular on your omni lights. on the top view you can see the reflection parallel to the viewing angle..

Jackpot! That was it!
I wonder if that wouldn't have happened if I set the light to Inverse Square. I set these lights to Inverse as I was having problems getting them to reach as far as I wanted without burning any other parts. Setting to Inverse seemed like a quick-fix.