Hi everyone,
I’m trying to do this: i want a building slowly start to emit blue light. To do that i simply animate the strenght of the emission while setting its color to blue, of course.
The problem is: when the emission is strong enough to reach the effect i need, the whole building becomes a solid light blue and the basic color is not visible anymore.
Is there a way to control the two things separately? I want the blue emission but i want to have control over the color of the building too.
Moreover: if i want to have some transparency i can’t find a way to make it work. If i use “Render method > dithered” the alpha doesn’t work, if i use blended the emission is not emitting on other objects anymore…
Thank you for you help, as always
You can use light linking to restrict lighting to some objects, to avoid some objects to receive it.
That is based on object level.
If you want a distinction more subtle, you need to do it in compositing.
Compositing allows you to use custom masks or mattes corresponding materials or AOV passes to control what is lighten ad what is not.
At compositing step, you can modify what you want, set the colors as you want.
In Eevee, emission works only through screen space raytracing. This means you can’t control an object’s light emission separately from the material’s brightness, at least not directly. You could do it by using light objects to cast more light than the material would allow. The only other way would be to use compositing to alter the material after the render is complete.
It should work, it’s just that it will be pixellated instead of purely transparent. If you render dithered with enough samples, it will eventually converge toward smooth transparency, though it can take lots of samples. But it’s the price to pay for a transparent object to react like a solid one in the render (dithered works by alternating opaque and transparent pixels, so it can support the same features as opaque meshes).
The blended mode doesn’t cast light, because it’s rendered separately from the rest of the scene and added back in, which is why it can have such clean transparency. The consequence is that it will be excluded from screen space effects.
This is absolutely how it should be done. Render a pass for No Blue, and Full Blue. Far more control over everything.
Thank you guys
In the end, like suggested, i opted for a point light, for now. I have to just make a little proposal. Then for the final animation, if accepted,i will compose that.
Thanks a lot.