That is not how lights work. Not even in ray tracing. In ray tracing or path tracing, either shoot rays in all directions, or towards the light. So the normal of the emissive mesh is not relevant. What it tries to figure out is that if a light is visible from a point or not. Imagine you "sit" on a certain point of the environment. Do you see the light source? If yes, then you are lit. If not, then you are in shade. This can be extended with bounces but the rule stays the same you just move to the next point.
In Corona renderer, 3dsmax u can control the directionality of a light plane. Kinda like spot lights when you want to make a spotlight u adjust the angle.
Alright I see what you mean. It still works like I described, with one extension. It checks the angle between the forward vector of the spotlight and the incoming ray. A spotlight is just a pointlight with a mask. No you can't do this with emissives.
In real life, a spotlight is a pointlight with a "mask" like I described. Its encapsuled in some open shape. That way, the light can only exit on the opening of the object.
What you describe should technically be possible, but these systems aren't made with this in mind. Instead of the forward vector of the spotlight, normal direction should be taken into account when this check occurs. But its not there.
Ok. Thanks. Btw, would you knoiw how to zoom into a camera which has its transform locked? I need to zoom into the camera like a picture with no perspecive change like pure ref. In 3dsmax, u have the 2d perspective zoom.
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