Author Topic: Light material in Ray-Switch  (Read 7770 times)

2016-01-24, 17:03:29

mraw

  • Active Users
  • **
  • Posts: 151
    • View Profile
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.

2016-01-24, 19:08:10
Reply #1

romullus

  • Global Moderator
  • Active Users
  • ****
  • Posts: 6087
  • Let's move this topic, shall we?
    • View Profile
    • My Models
There's been similar report recently: https://corona-renderer.com/forum/index.php/topic,10853.0.html
Lets wait for devs answer. I'll move topic to bug reporting board, if there will be no response.
I'm not Corona Team member. Everything i say, is my personal opinion only.

2016-01-25, 10:40:35
Reply #2

mraw

  • Active Users
  • **
  • Posts: 151
    • View Profile
Ok. Many thanks, Romullus.

2016-01-25, 12:49:15
Reply #3

Juraj Talcik

  • Active Users
  • **
  • Posts: 3763
  • Tinkering away
    • View Profile
    • studio website
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.
talcikdemovicova.com  Website and blog
be.net/jurajtalcik   Our studio Behance portfolio
Instagram   Our studio Instagram, managed by Veronika

2016-01-25, 13:47:40
Reply #4

mraw

  • Active Users
  • **
  • Posts: 151
    • View Profile
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?


2016-01-25, 17:47:56
Reply #5

maru

  • Corona Team
  • Active Users
  • ****
  • Posts: 9269
  • Marcin
    • View Profile
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

2016-01-25, 17:57:46
Reply #6

mraw

  • Active Users
  • **
  • Posts: 151
    • View Profile
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.

2016-01-27, 09:56:41
Reply #7

mraw

  • Active Users
  • **
  • Posts: 151
    • View Profile
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?

2016-01-27, 11:47:09
Reply #8

maru

  • Corona Team
  • Active Users
  • ****
  • Posts: 9269
  • Marcin
    • View Profile
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.

2016-01-27, 16:30:31
Reply #9

mraw

  • Active Users
  • **
  • Posts: 151
    • View Profile
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

2016-01-27, 17:03:12
Reply #10

maru

  • Corona Team
  • Active Users
  • ****
  • Posts: 9269
  • Marcin
    • View Profile

2016-01-27, 17:52:48
Reply #11

mraw

  • Active Users
  • **
  • Posts: 151
    • View Profile
Yes, because the cloned teapot occupies exactly the same space?
it seems to confuse Max what's behind and what to show/render.


2016-01-27, 18:03:40
Reply #12

maru

  • Corona Team
  • Active Users
  • ****
  • Posts: 9269
  • Marcin
    • View Profile
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?

2016-01-28, 10:54:40
Reply #13

romullus

  • Global Moderator
  • Active Users
  • ****
  • Posts: 6087
  • Let's move this topic, shall we?
    • View Profile
    • My Models
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'm not Corona Team member. Everything i say, is my personal opinion only.

2016-01-28, 11:37:00
Reply #14

mraw

  • Active Users
  • **
  • Posts: 151
    • View Profile
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.