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The Black Diamond
Posted: Tue Oct 02, 2018 6:06 pm
by SurfingNerd
Hello,
i just started with blender and LuxRenderer,
and i am stuck with a rendering:
(The diamond is laying on a plane)
i am trying to create a rendering of a diamond,
thanks to some tutorials i came already pretty far.
i am very satisfied with the dispersion and refraction of the lightrays on the ground,
but the diamond itself appears very dark.
any idea ?
there are 2 spotlights shining on the diamond.
blender version 2.79b
LuxCoreRenderer 2.0
Ubuntu 18.04
Re: The Black Diamond
Posted: Tue Oct 02, 2018 6:09 pm
by Dade
SurfingNerd wrote: ↑Tue Oct 02, 2018 6:06 pm
but the diamond itself appears very dark.
any idea ?
This is likely to happen because of the black background (reflected by the diamond). Try to use an HDR background or just a white one.
Re: The Black Diamond
Posted: Tue Oct 02, 2018 7:54 pm
by SurfingNerd
thx for the answer.
here the scene in a brighter light:
- settings_world.png (11 KiB) Viewed 3133 times
the diamond is indeed reflecting the world box colors.
but it shouldn't it reflect/refract the light from above as well ?
shouldn't the concentrated light on the ground be reflected back into the crystal as well ?
Re: The Black Diamond
Posted: Tue Oct 02, 2018 10:01 pm
by Dade
It looks like you have to increase the "gain" a lot (may be to 10.0, try to do some test).
What main light source type are you using ? A point light ? Try also to replace the point light with 1-3 quads emitting light. You probably want to simulate a studio-like light setup.
Re: The Black Diamond
Posted: Thu Oct 04, 2018 9:03 am
by SurfingNerd
Thank you for your help!
I had used spotlights from above in the scene.
I have done further experiments and now i have a deeper understanding of the issue:
Light direct from a lightsource get ignored by the camera.
I have set up a scene here with some point lights and replaced the ground with a mirror.
Maybe there is a trick or a setting to stop this ignorance ?
Here the layout of the Spot lights and the new Point Lights
Even the scene is full of lights with direct camera hits, most of the scene stays dark
What you can observe if you replace the Mirror ground with a matte ground.
Re: The Black Diamond
Posted: Thu Oct 04, 2018 9:48 am
by Dade
SurfingNerd wrote: ↑Thu Oct 04, 2018 9:03 am
I have done further experiments and now i have a deeper understanding of the issue:
Light direct from a lightsource get ignored by the camera.
I have set up a scene here with some point lights and replaced the ground with a mirror.
Point lights have no extension so they are not visible if you look at them (or trough a mirror). It is the reason why I was suggesting to use a quad area lights so they are visible.