Need help ASAP, advanced lighting

[MKVR1408]

I need to have this done in a week, please help me.
I’m working on a fairly simple 5-minute animation, little to no movement except for the camera, but I need to make some very advanced lighting, which I can not figure out how to do.

In a nutshell, I need the character model to be pitch black, as if no light was falling on it, but still have a shadow. A few times I want to illuminate some parts of it, like a flashlight or something similar passed over it, but otherwise I just want it completely dark.
So a shadow created by a model which can not have light falling on it, except a few times when I want it to have that.

I suspect I can reach there somehow using nodes, but I am very much a Blender beginner and have no real idea of what I’m doing. I really need help and would appreciate cohesive instructions from anyone who knows what to do.

[Thijs_Linssen]

I would do it after. So make on render with only the shadow of the character. And one with some lighting on it. Then use after effects or i guess it can be done in blender to get the effect you want. This way you can easily play around with it.

[Photox (Tim Gregory)]

For cycles the basic nodes would look something like this. The mix shader value can be keyframed by right clicking to blend between the two shaders.

[zeealpal]

Why not make the characters material pitch black? Just turn on any shininess/reflective settings, and set the main colour to black?

[MKVR1408]

Because then no light would be able to fall on it. I want to be able to light it with a secondary light source.

[MKVR1408]

@Photox

For cycles the basic nodes would look something like this. The mix shader value can be keyframed by right clicking to blend between the two shaders.

[ATTACH=CONFIG]458212[/ATTACH]

Would that let me light it with a second light source?

[MKVR1408]

@Thijs Linssen

I would do it after. So make on render with only the shadow of the character. And one with some lighting on it. Then use after effects or i guess it can be done in blender to get the effect you want. This way you can easily play around with it.

I’m not entirely sure I understand. You want me to make two models - one reflective and one not - and juxtapose them somehow?

[RamboBaby]

Try this:
https://www.blender.org/forum/viewtopic.php?t=20922

It’s really not anything advanced…very simplistic actually.
There are also other material settings like turning off specular shading, shadow only receiving materials, setting an object to only cast shadows by making it not visible to the camera (this still leaves it visible to raytraced shadows and reflections thus allowing you to have a duplicate object occupying the same space without the crazy things that would otherwise occur at rendertime), etc… You can also set up duicate scenes and import some specificic parts into the compositor and recombine the scenes.

[MKVR1408]

@RamboBaby

Try this:
https://www.blender.org/forum/viewtopic.php?t=20922

It’s really not anything advanced…very simplistic actually.
There are also other material settings like turning off specular shading, shadow only receiving materials, setting an object to only cast shadows by making it not visible to the camera (this still leaves it visible to raytraced shadows and reflections thus allowing you to have a duplicate object occupying the same space without the crazy things that would otherwise occur at rendertime), etc… You can also set up duicate scenes and import some specificic parts into the compositor and recombine the scenes.

Funny thing is as I was waiting for a reply I managed to solve it myself, and what’s even funnier is I am not really sure how I did it.
That said I also have a new problem. For some reason the back of the head and neck of the model isn’t illuminated as the light passes over it, but the chest area is despite them both having the same UV map. I’ll create a seperate thread for that, but would you have any idea what’s going on?