I have a Light Material plugged in the GI-slot. A black material is in the direct visible-slot.
However the LightMaterial is directly visible. Only when I uncheck ‘Emit Light’ the black material is visible.
Is this a bug or is my understanding of the rayswitch limited?
thanks.
There’s been similar report recently: Help with using Corona Light Mtl and RaySwitcher - Corona for 3ds Max :: Help Required - Chaos Forum
Lets wait for devs answer. I’ll move topic to bug reporting board, if there will be no response.
Ok. Many thanks, Romullus.
This is nothing recent, it worked like that when I used it year ago.
I absolutely do not get the idea behind Rayswitch, works polar to how it’s implemented in Vray. Instead of using override for what I need I have to separate it into all slots.
The Lightmaterial use inside was so painful I never used it again.
It is working with a standard material with self illumination turned on. But this gives me pretty noisy renders.
So I went for the Light Material in the GI-Slot.
When I uncheck the ‘Emit Light’ checkbox: What I get is equivalent to SelfIllumination?
I will try to get back with some explanations tomorrow, but now I can only post this for info about differences between self illumination and light mtl:
https://coronarenderer.freshdesk.com/support/solutions/articles/5000515603
Thanks. I know this link and the selfIllum. is by far not the brightest or main light in the scene.
But I bumped the value up, just to see a little bit of spill light in the nearer environment.
Sorry for bumping this thread up. But I really have to know if this behaviour of Light material in GI-slot is faulty.
And if yes: How can it be fixed? Is there a workaround?
Just to make sure I understand everything - the idea is to make a light using light mtl that will glow (illuminate scene), but will appear as, for example, black sphere?
I didn’t find a good way to do it. It looks like what we see directly is actually the GI component of the light material.
A silly workaround is to disable light’s “visible directly” option (in reflections/refractions too if needed), duplicated it, assign black material to the duplicate, and exclude the duplicate from light’s influence.
An interesting approach, thanks. But to be honest I can’t reproduce it. Silly me.
Let me describe your suggestion with my own words.
- you disable ‘visible directly’ in the properties of the light material.
- clone the object and assign black shader
- exclude the clone from the light.
correct? thanks
Yes, that it exactly what I did. Does it produce a different result for you?
I don’t get it. Your glowing teapot is still visible despite the fact that you unchecked “visible directly”. Are you sure that you have right materials applied?
That’s hardly a workaround if it’s requires to fiddle with geometry. And it’s very impractical. maru, can you tell us if such Rayswitch behaviour is by design, some limitation or simply a bug?
I don’t think this workaround is something I want to do in production. But it is a good approach finding out
what’s going on.
I’m still not able to reproduce it- maybe some misconception on my side?
Without trying to reproduce the ‘exclude-copy’-thing:
capture1. Shouldn’t there be a black teapot in the viewport?
capture2. You could see ‘vis.dir.’ checkbox disabled. The preview render of the material works, but
not in the viewport and not in the render.
Here is the scene + example. I made two “black” materials. One will occlude the light, and the other one uses rayswitch to let it glow.
I know that this is not a real solution, but it’s the only one I could think of…
light-rs2-13.max (656 KB)
thanks a lot. Yes, that’s working fine.
Can we conclude that GI-slot in combination with light-material behaves oddly?
I would love to hear what Ondra might have to say about this.
Behavior of rayswitch+light seems counter-intuitive, but let’s wait for Ondrej’s explanation. I already notified him.
this is limitation of the fake system, light emitters cannot be ray-switched. When you disable emission, you turn the light into self-illumination, which is computed differently and can be ray-switched