Author Topic: physical mat | reflection intensity question  (Read 6386 times)

2022-01-31, 12:07:19
Reply #15

Stefan-L

  • Active Users
  • **
  • Posts: 503
    • View Profile
i am trying to use glass, as it is used in architecture, to suit our usual customers, so in a normal way, and glass is said to be much more realistic in new physical material overall.

i would love to eliminate the old legacy material use for most things, and i do think the new phy-material is the way to go for future, but also believe this one feature (reduce reflections) is needed to really create all usual real world materials with it.
glass is one of the #1 used materials in archviz, and atm is hard to use as it cant be tuned the needed way.

 i truly believe this would make it not less physical, as we have these controls in almost
very other material feature already now.

2022-01-31, 12:36:29
Reply #16

piotrus3333

  • Active Users
  • **
  • Posts: 230
    • View Profile
it would make it exactly that: non-physical. and I guess that was not the intention behind it.
Marcin Piotrowski
youtube

2022-01-31, 13:17:54
Reply #17

Stefan-L

  • Active Users
  • **
  • Posts: 503
    • View Profile
i dont think so to be honest.
these materials do exist in real world, and are pretty often used.
a physical material that cannot do often used real world mats isnt yet really physical, for my understanding at least.

and second we are still artists and need to react to our customers wishes.
Corona is a tool for artists as far i understand it, and its target is to provide us a good and easy to use work flow.
the future of the phy-material will be only bright if it let us make the usual daily needed material tunings

this is what i mean, it is available in almost any other material feature already, so adding it would be consist i think:

« Last Edit: 2022-01-31, 13:25:16 by Stefan-L »

2022-01-31, 20:05:24
Reply #18

burnin

  • Active Users
  • **
  • Posts: 1532
    • View Profile
Then it will not be light Aluminium, but a dark metal.
True.

Quote
I attach the file, I hope you will show it as it should be?
I see problem arising from Corona Sun.

Note:
This also occurs in photography. So avoid shooting/rendering in direct sunlight is best you can do. Either lower Sun's Size & Intensity or use an IBL/HDRI on the Sky. (In photography you'd have to do multi-bracketing and then composing in post.)

Quote
... and also, if you switch the material from "Non-metal" to "Metal", then even the IOR becomes unavailable. How to regulate?
It's there, in Physical Material, under Advanced tab >  Complex IOR

With PBR technique it's advised to take photographer's approach to lighting & shading, look dev.
« Last Edit: 2022-01-31, 20:08:47 by burnin »

2022-01-31, 20:31:32
Reply #19

Stefan-L

  • Active Users
  • **
  • Posts: 503
    • View Profile
"With PBR technique it's advised to take photographer's approach to lighting & shading, look dev."

well a photographer taking a shot of such a reflection reduced glas will get the right result,
exact that option i wish for the new corona mat, to recreate reality;)

2022-01-31, 21:31:36
Reply #20

TomG

  • Administrator
  • Active Users
  • *****
  • Posts: 5434
    • View Profile
I think it was mentioned earlier that such glass has a special coating, and we can't incorporate controls in the one material that allow for every sort of extra coating (ie extra material) that can be added one top. The clearcoat covers the most common coatings, ones which increase reflectivity. Not sure what kind of extra coating would reduce it (in my museum glass for a framed painting, the reduced reflections are in fact rather green).
Tom Grimes | chaos-corona.com
Product Manager | contact us

2022-01-31, 22:18:57
Reply #21

aler

  • Active Users
  • **
  • Posts: 170
    • View Profile
I see problem arising from Corona Sun...
This also occurs in photography. So avoid shooting/rendering in direct sunlight is best you can do....
...under Advanced tab >  Complex IOR
Probably everyone has their own ideas about how to do it right.
For me responding to every replica is very tedious. Instead I answered here.

2022-01-31, 22:42:57
Reply #22

burnin

  • Active Users
  • **
  • Posts: 1532
    • View Profile
Sorry, that last post wasn't directed at you...
... nonetheless, I still have to find such magical glass. Most of what I've seen have slightly reduced reflection, nowhere near to marketing claims. Especially with right lighting conditions you can break an illusion easily ;) 

Even Saint-Gobain have a disclaimer:
Quote
Important
The residual reflectance of VISION-LITE anti-reflective glass is very low (approximately 1% for laminated
monolithic glass). It is however still visible under certain lighting conditions, viewing angles and in certain
surrounding environments. The residual reflectance depends on the angle from which it is viewed.
Perpendicular to the glass, it is slightly bluish and can vary slightly. For external applications (eg: shop
fronts), it is strongly recommended that a sample is viewed in the intended location.

Their measurements are done head on @90°
& Fresnel still does its physical correctness.

PSMaybe there's a way to get tabulated data into Corona & then mimic SGG's.
Otherwise, I'd consider Legacy a perfect solution for such cases.

2022-01-31, 23:00:32
Reply #23

burnin

  • Active Users
  • **
  • Posts: 1532
    • View Profile
Probably everyone has their own ideas about how to do it right.
For me responding to every replica is very tedious. Instead I answered here.
Gee...
Do note that that request is about the Legacy Material.
Also, I was under impression you seek physical way & a solution to particular problem. And about artistic "right ways of doing something", there are as many as there are artists.
So do, Be well

2022-02-01, 14:57:01
Reply #24

jojorender

  • Active Users
  • **
  • Posts: 241
    • View Profile
+1 to all that Stefan-L is saying.
and second we are still artists and need to react to our customers wishes.
Corona is a tool for artists as far i understand it, and its target is to provide us a good and easy to use work flow.
the future of the phy-material will be only bright if it let us make the usual daily needed material tunings

I also understand corona’s approach to make the PBR MAT “fool proof” because users can’t be trusted. That’s why the base layer color value needs to be restricted between 7% and 93%
Ok, I’M KIDDING, or am I?
Back to the issue, everyone that worked with real clients knows that they care very little, if at all, about what’s physically correct. That includes architects that, you would assume, are interested in “a real world” representation of materials.
A friend of mine is a architectural photographer working with big name arch firms, and we talk about the absurd retouching requests he gets. Reflections are always a battle.
In my early days I worked in a photo studio, and pol filters for lights and lenses were in daily use. Anything to kill unwanted reflections.
So, while the quest for physically correct*** materials is honorable and probably prevents many disasters, a “reflection value” slider is absolutely needed.

If this is not possible in PBR mat, please reassure us that the legacy material is here to stay, by renaming it to “experimental” or “DO NOT USE”  or whatever prevents the casual user from touching it.
***lol - my autocomplete just made “physically corrupt” out of “physically correct” - says it all.
« Last Edit: 2022-02-01, 23:48:41 by jojorender »

2022-02-02, 13:22:37
Reply #25

Pepelecrabb

  • Active Users
  • **
  • Posts: 96
    • View Profile
Ha, I was thinking (joking) in the back of my mind, they just need to add a polarizing filter to the Post Render. Perhaps like negative numbers under Bloom and Glare.
And, if they would add swing and tilt to the Corona Camera it would be just like the old days.

2022-02-02, 23:09:48
Reply #26

Stefan-L

  • Active Users
  • **
  • Posts: 503
    • View Profile
guys really,

beside all other, - how you imagine we cope with very very usual requests from customers:  "please make glass reflection lot less" ?

can someone explain me, what i shall tell the customers? "No i cant, - it is not physical"? ;)
(and yes we all should use the new material not the old legacy of course)

2022-02-02, 23:23:43
Reply #27

piotrus3333

  • Active Users
  • **
  • Posts: 230
    • View Profile
why not? legacy mtl is not going anywhere. another option I see is asking devs for additive blend mtl.
Marcin Piotrowski
youtube

2022-02-02, 23:56:26
Reply #28

TomG

  • Administrator
  • Active Users
  • *****
  • Posts: 5434
    • View Profile
Ideas on controlling reflection:

- Flat glass such as windows etc. does not show any refraction effect, reducing IOR will not change refraction in terms of how things look in your render, but will reduce reflection

- For rare cases such as specialist glass that is not flat, render to separate elements and combine in post, using masks (up to and including the new Cryptomatte) to isolate objects and adjust their reflection separately during compositing

- Use Legacy material for breaking the laws of physics when your client won't be happy any other way

(BTW museum glass, apparently works with a coating and I guess using a specific thickness such that reflection from the inner surface of the glass destructively interferes with the reflection from the outer surface
t=96s - not sure that could actually work with non-flat glass anyway tbh)

Tom Grimes | chaos-corona.com
Product Manager | contact us

2022-02-03, 04:32:13
Reply #29

jojorender

  • Active Users
  • **
  • Posts: 241
    • View Profile
legacy mtl is not going anywhere.

Ah ok, thanks for confirming this! Didn't realize you are a Corona Team member.