Author Topic: Reflections in Physical material  (Read 1090 times)

2021-09-21, 18:07:36

masterzone

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Hello all, name's Alex
I using Corona since V4. Now I'm play with v7 Physical Material system, I've a question:
How can I dim the reflections on a GLASS Mat as previously materials?.
With previously GLASS Mat (legacy) when I turn the Refractions and reflections on I can dim the reflection layer by using the IOR....now all has been "merged" on a unique IOR parameter.

E.g. I create a GLASS Box on a bathroom, and I see that the reflections are to much...now with only one IOR is very hard...
Thanks for any tips!

2021-09-22, 12:39:21
Reply #1

Beanzvision

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Hi there, have you tried enabling ''Thin shell'' from under the ''General'' and then played with the IOR settings in the base layer? Also, adding a small of roughness might reduce the reflection amount as well. I think providing an example image might help here too.

2021-09-23, 08:30:14
Reply #2

masterzone

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Thanks for your tips, but by enabling the Thin Shell you will internally turn off the refractions IOR, so you will unable to create a real glass plate...

Sorry if I don't attached any image but the example is very easy to understand: How we can low the strength of the reflections on a glass if the IOR is a global parameter?
On a legacy materials the Reflection layer has separated IOR so I can adjust the strength of the visible reflections or by using the Reflections Color...

Now is impossible with physical material....

2021-09-23, 11:56:04
Reply #3

TomG

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And is impossible via IOR in the real world, as any real material only has one IOR that affects both reflection and refraction :) Which is why the design of the physical. (BTW, a glass plate, being flat, really shouldn't show any bending of light due to refraction, which is why Thin is recommended for windows, car windshields, etc.)

2021-09-23, 12:11:34
Reply #4

masterzone

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Yes, if a material has the same IOR for reflections and refractions using the physical material is a great way to achieve the results. But if you have a glass with some anti-reflections coating you need to adjust the reflections IOR separately...
I understand that the Physical material has the locked IOR for both channels but in the "real world" is not true this way because the "refractions IOR system" is not the same of the "reflections IOR system". The first one is a ray that pass through the surface and is physically correct, but the second one is a ray that hit the surfaces and the GLASS needs a second controller for the final results. As I wrote on my previously messages, how can I dimm a reflections into a car windshield? dimmed by an anti reflections coating treatment?

Quote
(BTW, a glass plate, being flat, really shouldn't show any bending of light due to refraction, which is why Thin is recommended for windows, car windshields, etc.)

ehm...IMHO is not the right way to achieve a glass. Thin shell is used for poly surface without internal volume mass. Glasses must be created with IOR and thin shell turned off otherwise you will render two separated flat surfaces...take a look to attached image.. (LEFT plate a standard Glass, on the RIGHT the Thin shell turned on)

Anyway no problem, now I understand that the Physical material has not way to dimm the IOR reflections...
Thanks for your time

Alex :)
« Last Edit: 2021-09-23, 12:29:33 by masterzone »

2021-09-23, 14:25:34
Reply #5

burnin

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There are types of glass (& other surfaces, especially metals) where nano-coating or oxidation lowers/changes surface reflectivity. So it's now commonly expected that "Clearcoat" should influence reflectivity in same way, but it doesn't. I guess it's not fully implemented yet, since it also shows issues w/ iridescence (in C4D), which should also be property featured in Physical material (as diffraction is).

I get limits and flaws, since this is just a first iteration of Physical material after all.  Now only thing left is to use "Legacy" material for time being.
Still, do continue with proposals and ideas.