Invisible light reflections in cycles

I have made some invisible lights, and under their object properties I have unchecked:
camera, diffuse, transmission and shadow (only glossy is checked).
Underneath the lights there is shiny floor, and although I cannot see the lights in the scene :slight_smile: i can see them relflected in the floor :frowning:

PLease can someone tell me what I am doing wrong? I do need the floor to be reflective for other assets.


It’s not just that the energy of the light is so strong it lightens the floor rather than it being a reflection?

Cycles Glossy shader does not honor the flags, I noticed this as well.

Isn’t it so that shiny=glossy and camera is supposed to see exactly this?

Are you meaning the flags in the object context because the node method works.

The light is in the middle of the viewport, but it’s not being reflected nor is it being seen.

The error only shows up when you increase the roughness of the Glossy shader. So it works fine as an absolute mirror. This is why I call it an error. As soon as roughness is increased, bam an ugly light appears in your reflection. So a simple IF statement in the code could fix this.

As you can see in this image, the sphere, which has an emission shader, should clearly not contribute to the glossy processing, yet it does, only when roughness is greater than zero. Seems like a bug or at least an unwanted feature.


26_cycles_glossy_light_error.blend (526 KB)

Could it be that “glossy” is the equivalent of “singular” in ligthpath node? It would make sense to me

When I made that test scene, I also played with different roughness values, and it seemed to me that it’s just due to the illumination of the glossy material similar to what you would see on a diffuse surface.

I used a cube light for my test, and when I turned up the roughness a little, I did get a reflection, but I did notice that it was darker in the center of the reflection where the light would be, so I figured it may just be a product of the glossy surface being rough enough to cause a limited amount of diffusion.

So you see what I mean by my statement that Cycles is not honoring the Ray Visiblity flag. If it was, no part of the emission would be participating in the Glossy reflection.