I have a video background layer, an ambient light layer, a subject comp with alpha, and a spot light. I am using lux to shine the spot onto the subject layer. I am using the ambient layer to give both the subject and the background some light, about 40%.
1st off, what I want is for the spot light to cast enough light to light up the subject's face and body so that the overall look on these areas would be as if the ambient light were 100%. I want it to look like a spot light in a theater where the face is well lit but not overly washed out. I cannot find a balance using lux where the subject is not washed out with the spot light, even if I turn the ambient down to zero. Are there some magic settings that I should try to accomplish this feat? I do not mind washing out my background.
Next, I'm trying to figure out how shadows work. I'd like the subject layer to block some of the spot light from casting onto the background. But I cannot see any shadows anywhere and I have turned on accept and cast shadows on these layers. The layers are really 2d layers with the 3d check mark added so that light will work. I've tried moving the subject and background layers in all axis but I can't ever find any shadows anywhere. Is there a a good resource where I might learn more about shadows that would help me here?
Honestly I have no idea what you are talking about and think you are approaching this the wrong way.
a) Lux does not calculate volume shadows - it's an annoyance, but I understand why Trapcode made it this way. Volumetric shadows are a speed killer. Makes the plugin a bit redundant and useless, though, since all its effects can be faked/ created with other techniques.
b) AE layers do not self-shadow, since they are only flat planes. You would have to fake those shadows as well.
c) That part about the ambient I understand the least. You should try to adjust the shading properties of the 3D layer, not moosh it up by placing other layers on top. If any such thing, you should do it in the pre-composition and use layer blend modes such as Screen or Add.