Author Topic: Corona Ray Switcher in glass changes refraction?  (Read 3895 times)

2020-11-10, 19:06:34

lupaz

  • Active Users
  • **
  • Posts: 951
    • View Profile
Hi,

I need to have more light bouncing off some glass that you can see here.
So I wanted to use a Corona Ray Switcher for the bounced light only while keeping the same look on the glass.

I'm not sure why the sunlight doesn't seem to go through the glass. Something's strange.


Thanks.

2020-11-10, 19:20:15
Reply #1

maru

  • Corona Team
  • Active Users
  • ****
  • Posts: 12711
  • Marcin
    • View Profile
What kind of glass material is it? Refractive, thin? Does it have reflection or refraction glossiness lower than 1? Some volumetric properties?
Would you be able to share a simple scene demonstrating this ?
Marcin Miodek | chaos-corona.com
3D Support Team Lead - Corona | contact us

2020-11-10, 19:34:02
Reply #2

lupaz

  • Active Users
  • **
  • Posts: 951
    • View Profile
What kind of glass material is it? Refractive, thin? Does it have reflection or refraction glossiness lower than 1? Some volumetric properties?
Would you be able to share a simple scene demonstrating this ?

See the material attached please.
To send the scene I would need more time. I can't right now. Let me know if you still need it and will send it tomorrow.
Thanks.

2020-11-10, 19:52:02
Reply #3

romullus

  • Global Moderator
  • Active Users
  • ****
  • Posts: 8779
  • Let's move this topic, shall we?
    • View Profile
    • My Models
How light could go through, if you plugged opaque material into global illumination slot? Your setup doesn't seem to make any sense. If you want more light bouncing off the windows, then maybe it's worth try to turn the caustics on?
I'm not Corona Team member. Everything i say, is my personal opinion only.
My Models | My Videos | My Pictures

2020-11-10, 20:06:14
Reply #4

lupaz

  • Active Users
  • **
  • Posts: 951
    • View Profile
How light could go through, if you plugged opaque material into global illumination slot? Your setup doesn't seem to make any sense. If you want more light bouncing off the windows, then maybe it's worth try to turn the caustics on?

But for refract I left the original material.
I wasn't expecting an opaque material in global illumination to affect refractivity.

2020-11-10, 21:23:39
Reply #5

romullus

  • Global Moderator
  • Active Users
  • ****
  • Posts: 8779
  • Let's move this topic, shall we?
    • View Profile
    • My Models
The glass is still refractive, it just there's not much what to refract, since behind it is total darkness and that's because global illumination override is opaque. AFAIK, global illumination controls the light rays and refraction/reflection controls visible rays.
I'm not Corona Team member. Everything i say, is my personal opinion only.
My Models | My Videos | My Pictures

2020-11-12, 18:56:11
Reply #6

maru

  • Corona Team
  • Active Users
  • ****
  • Posts: 12711
  • Marcin
    • View Profile
Yeah, this is the expected result. If you plug a solid material into the GI slot, it will basically block all light (cast solid shadows).

I did not understand this part:
Quote
I need to have more light bouncing off some glass that you can see here.

Can you explain what kind of effect you are after? I should be able to help with this.
Marcin Miodek | chaos-corona.com
3D Support Team Lead - Corona | contact us

2020-11-12, 19:37:11
Reply #7

lupaz

  • Active Users
  • **
  • Posts: 951
    • View Profile
Thanks Maru.
What I need to do is have caustics bouncing off the glass. However, turning caustics ON gives me just what it looks like a noisy photon map.
So I thought changing the GI slot to a white material to get more "fake" bounced light.
The effect I'm looking for is like the attached.
The light bouncing off the glass brightens the area in shade.
I could just add area lights, but I was wondering if there was a better way.



2020-11-12, 19:45:20
Reply #8

TomG

  • Administrator
  • Active Users
  • *****
  • Posts: 5434
    • View Profile
Hmm that should work just fine with caustics, I had a test done back when they were released that did exactly this, with no need for any overrides. Can you share what results you are getting with caustics (without overrides), whether your glass is thin, the scale of your scene?
Tom Grimes | chaos-corona.com
Product Manager | contact us

2020-11-12, 19:47:37
Reply #9

TomG

  • Administrator
  • Active Users
  • *****
  • Posts: 5434
    • View Profile
(as a note, best if caustics are not generated by the environment, but by a single bright strong light source such as a Corona Sun only)
Tom Grimes | chaos-corona.com
Product Manager | contact us

2020-11-12, 20:03:36
Reply #10

TomG

  • Administrator
  • Active Users
  • *****
  • Posts: 5434
    • View Profile
As a note, here was my test render where I was experimenting with that very thing (no denoising used here, and not run for very long, just to illustrate they shouldn't be splotchy even without denoising and a decent amount of rendering).
Tom Grimes | chaos-corona.com
Product Manager | contact us

2020-11-12, 20:35:56
Reply #11

lupaz

  • Active Users
  • **
  • Posts: 951
    • View Profile
Hmm that should work just fine with caustics, I had a test done back when they were released that did exactly this, with no need for any overrides. Can you share what results you are getting with caustics (without overrides), whether your glass is thin, the scale of your scene?

Thanks Tom.
My glass is not thin.
The system units are inches.
Corona Sun has "generate caustics" checked.

I'm sending below a rendering showing the bright spots.
Also sending the simplified scene.
I tried 4K and UDH cache.


2020-11-12, 20:37:26
Reply #12

lupaz

  • Active Users
  • **
  • Posts: 951
    • View Profile

2020-11-12, 20:47:00
Reply #13

Frood

  • Active Users
  • **
  • Posts: 1903
    • View Profile
    • Rakete GmbH
However, turning caustics ON gives me just what it looks like a noisy photon map.

If you mean just the caustic solver in performance tab, looking at  the screenshot here it seems like you have just not activated caustics in your glass material :)


Good Luck



« Last Edit: 2020-11-12, 20:51:32 by Frood »
Never underestimate the power of a well placed level one spell.

2020-11-12, 21:12:03
Reply #14

lupaz

  • Active Users
  • **
  • Posts: 951
    • View Profile
However, turning caustics ON gives me just what it looks like a noisy photon map.

If you mean just the caustic solver in performance tab, looking at  the screenshot here it seems like you have just not activated caustics in your glass material :)


Good Luck

I think that's for refractive caustics. I'm looking to get clean reflective caustics.