Light material + geo as a light source

[seandunderdale]

Hi, Im having an issue that Im sure didnt used to be an issue. I have some geo that is animated along a curve with a light material on (direct illum unticked). This geo is hidden and casts light into the scene as it animates which is great. There are also other vray lights in the scene, and these cast shadows. My issue is, the geo on the curve is having its shadow cast onto the scene via the other lights. If I turn shadow casting off on the hidden curve geo with the light material on it, it suddenly doesnt cast any light at all. Light linking also doesnt fix it. Im not sure why a geo object now isnt able to cast light, whilst not casting its own shadow.

[seandunderdale]

ok...having tested, it seems turning on "direct illum" fixes it. I remember this also killing some of my render times in the past which is why Ive avoided it.

Edit....ok, so turning on direct illum seems to override the "not visible in reflections" i had setup. I Might be wrong but this was very simple a couple of yars back, now it seems a simple thing has been made complicated or impossible.

[hermit.crab]

Not sure how you've hidden the object, but disabling the "Primary Visibility" and "Visible in Reflections" plus enabling the Direct Illumination should do the trick. Check this simple scene.

[seandunderdale]

interesting....I tried those..Im fairly sure...I mean this should be about as simple as it gets, which is why I was surprised I couldn't fix it. Admittedly its been crunch time with a lot of late nights recently so WHO KNOWS! Thanks for the scene, I will test.

[seandunderdale]

OK, try to see if you can get rid of the reflections in the floor in this scene. Its your scene with a minor tweak to the floor shader gloss

[hermit.crab]

Using a "Reflection Exclude List" (as Inclusive with everything except the VRayLightMtl ) in the Plane object does the trick, however, this solution is quite crude. Problem is, although the VRayLightMlt with DI acts as a Light, it does not have "Affect" options like regular lights. I think you'd be better off using a VRayMeshLight instead.

[seandunderdale]

ok cool...Ill check the reflection exclude list....I've never actually used it before so it never occurred to me. Mesh light is an option, I will test that....I remember trying that for a shot that had env fog once (my current shot does too) and render times went nuts. But Ill try it out and see. Cheers!

[seandunderdale]

Tried exclusion lists and they didnt seem to work with my blurry ice shader. I needed a mirror surface for it to work. Turning my geo into a mesh light did work though and solved the issues I had. Didnt test render time, but at least the visual issues in the render were fixed.