View Full Version : Glowing object adds to brightness of backgorund texture?

08-20-2016, 05:05 PM
Hi everyone,

I am posting on behalf of my artist who is working on a 3D scene for me... Basically, we've got a space scene, there are stars and clouds, and on top of that, there are blue lines that are glowing. It appears that the glow of the blue lines adds to the brightness of the background texture as you can see here:


The places where the bright parts of the space background intersect with glowing object cause the glowing object to get brighter... How can this be fixed?


Also, there is an explosion that happens in the animation, and the light from the explosion is also making the background "space clouds" get brighter. The artist says the background is already excluding all lights, and that it's an alpha channel problem. Does anyone know how this can be fixed?

08-20-2016, 06:04 PM
without knowing more of what is in the scene (image types and how it is applied to the background) easiest thing would be to render the background and foreground separately then comp them together after

08-20-2016, 06:26 PM
When you say comp them together, can lightwave do that? Or should I do that in a video editor?

08-20-2016, 10:42 PM
Technically speaking, that is what is supposed to happen. Energy adds up or subtracts from other energy. According to physics, there is nothing to be "fixed". That is what is happening in your scene. It is simply not that which you expected to see. Most probably, your background is too bright for actual conditions. Nebulae are not very luminous compared to other sources, but portraying them in their actual state isn't sexy, so people pump them to absurd levels in order to make it look interesting.

Your only path would be to render separate passes for the elements in question and comp them together in After Effects, Fusion or similar in order to control the amount of addition of energy sources seen in line with each other.

08-20-2016, 11:26 PM
Which is a good idea anyway, because your control and SPEED is so much better. Comp it.

There's several free compositors if you don't want to shell out cash, or just have very limited needs.

08-21-2016, 12:34 AM
it might be that the DPont BufferNodes can do it, probably, but i'm no expert at it...

a render setup from Gerardo Estrada