Lamp Design


I’m designing some lamp shades for a cnc machine so I’m using a scale of 1 blender unit as 1mm and using cycles to test shadow casting.

Currently I’m using a stretched uv sphere as an emitter for the bulb (dia 20, height 40). There is also a basic enclosing room comprising of faces (with inward pointing normals), dimensions 4000x5000 with a height of 2500.

To get the shadows to hit the walls I have set emission to 10,000. No AO currently.

The results aren’t looking great at the moment, just shadows on the ceiling and not really on the walls. The lamp shade is totally burnt out white.

Are there any tips you can suggest please?

(I’ll post images later when home, currently on phone)

Oh, using Blender 2.78

Emission set 100,000 not 10,000

I would guess the problem is not with the render (I can take a look, though, if you post the blend file).

One needs to consider, that this kind of scenes are intrinsically very HDR (high dynamic range). If you think about how it would be in reality, looking directly at the lamp will almost blind you, while it still it weak enough for only dimly light the room.

The best way to solve the problem is probably to do it in the compositor. The primarily thing to do there should be gamma correction, and like birghtness/contrast afterwards.

Wasn’t wanting to involve the compositor for this, I’ll go through some arch vis tutorials later, thanks

Just remembered another common trick to fix the lamp shade getting clipped white. Using the light path node, one can reduce the brightness of stuff when viewed directly, but still have it produce enough indirect lighting for the surroundings to be illuminated sufficiently.


lamp-camera-ray-trick.blend (747.4 KB)

Yeah, best to share the scene with the minimum amount of geometry that still causes the issue. Sounds like the scale is off though if you need 100000 strength light. 1 blender unit should be 1 meter, lights are affected by this. Also, try to use lamp based lights instead of emissive geometry where possible, as this tends to converge faster.