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Mats Andersen
01-25-2018, 02:46 AM
Hi Everyone, im getting more used to the new concept now, and I find it faster and better in many ways. Volumetrics got to be 100 times faster and much better looking.

There is one thing I wonder about. In many cases I get overly powerful speculars at low incidende angles. So too much fresnel. It can be a strong reflection of the sky, a light or HDRI highlight.

AS we now it doesnt help setting the specual setting lower unless you set it to zero. alternatively I have had to crank roughness up to 100% for some materials to dampen the highlight.
But I ve heard that specual tint would do the trick but it has zero effect as far as I have been able to do.

In 2015 - easy enough change the gradient of the fresnel.
It has to be a way within the PBR system as well.??

Typical material - asphalt. very low reflection, very rough. any ideas?
A forest seen from the air. many leaves become super bright pixles as they have the low incidence angle. I turn up roughess to kill it, but i dont feel this is the way to go.

best
Mats Andersen

Ztreem
01-25-2018, 04:59 AM
Hi Everyone, im getting more used to the new concept now, and I find it faster and better in many ways. Volumetrics got to be 100 times faster and much better looking.

There is one thing I wonder about. In many cases I get overly powerful speculars at low incidende angles. So too much fresnel. It can be a strong reflection of the sky, a light or HDRI highlight.

AS we now it doesnt help setting the specual setting lower unless you set it to zero. alternatively I have had to crank roughness up to 100% for some materials to dampen the highlight.
But I ve heard that specual tint would do the trick but it has zero effect as far as I have been able to do.

In 2015 - easy enough change the gradient of the fresnel.
It has to be a way within the PBR system as well.??

Typical material - asphalt. very low reflection, very rough. any ideas?
A forest seen from the air. many leaves become super bright pixles as they have the low incidence angle. I turn up roughess to kill it, but i dont feel this is the way to go.

best
Mats Andersen

This is how it works in real life. If a material is less reflective its more rough, so if you want a material to be less reflective increase the roughness.

Danner
01-25-2018, 05:48 AM
As a side note, if you just want to tint reflections, up the metalic property of the material.

gerry_g
01-25-2018, 06:40 AM
the docs say PBR is supposed to have fresnel built in as a value to each of the functions natively and that is why you don't have it as a stand alone input, but there is nothing stopping you from plugging a gradient into any given value such as roughness to ramp it up even more

Mats Andersen
01-25-2018, 07:53 AM
This is how it works in real life. If a material is less reflective its more rough, so if you want a material to be less reflective increase the roughness.

Hi yes I see the concept, but its not rough enough then at 100%. So i guess adding a gradient as suggestion made here can boost roughness. Will try this.


thanks guys. So what about the specular tint setting?? how does that apply?

Mats

RebelHill
01-25-2018, 09:20 AM
So, fresnel etc are built into principled because they're so common in so many materials. Also, they're "non-negotiable" in that material because its very purpose is to provide something realistic with minimal effort or knowledge on the part of the user. This doesnt make it suitable for EVERY possible surface type, just the majority.

As for ashphalt... it DOES have specular with fresnel, you have to get the right conditions in the real world to see it (rising, rolling road, strong sun, etc)

https://image.shutterstock.com/z/stock-photo-beautiful-highway-road-of-thailand-with-green-mountain-and-sun-shine-background-660299458.jpg

And the result is a very diffuse lightening, because, as you say, its so rough it doesnt look like a "reflection", but it is.

Your main options would be to either set spec to 0 and use sheen, or use standard and craft your own surface with the visual properties you specifically want.

gar26lw
01-25-2018, 09:42 AM
does standard behave and look the same as 2015 or has it been improved for 2018?

if not arenít you better off with 2015 for speed?

RebelHill
01-25-2018, 01:28 PM
Its similar, though its not the same. And no, because 2015 is not faster.