V-Ray 5: VrScans Clearcoat is blurred compared to Next

[Ivaylo Katev]

Probably the best solution for 5 is to load the measured glossiness specified in the sample when loading the material, but also the ability to override that value to 1, i.e mirror-like glossiness.

OK then, this is anyway sheduled and i will push it forward, perhaps in few days will be accessible in the 5.1 nightlies

[seandunderdale]

Thanks for the solution. I havnt done much testing myself, but on live shots I have noticed the difference in glossy reflections. I remember checking everything else in my scene to find why the paint was soft, but I was surprised to find it was the carpaint. No idea how to explain your tests showing the same results.

[Ivaylo Katev]

Thanks for the solution. I havnt done much testing myself, but on live shots I have noticed the difference in glossy reflections. I remember checking everything else in my scene to find why the paint was soft, but I was surprised to find it was the carpaint. No idea how to explain your tests showing the same results.

Which material? Only the materials scanned before Sep. 2019 must be equal in VRay 5 and 4. The material info contains a number called "build stamp" , if this number is bigger than 409270000 , the material contains glossiness and will be rendered differently in 4 and 5

[kosso_olli]

OK then, this is anyway sheduled and i will push it forward, perhaps in few days will be accessible in the 5.1 nightlies

Thank you so much!

[seandunderdale]

Which material? Only the materials scanned before Sep. 2019 must be equal in VRay 5 and 4. The material info contains a number called "build stamp" , if this number is bigger than 409270000 , the material contains glossiness and will be rendered differently in 4 and 5

It was a silver scanned paint. Im not sure right now exactly which it is. It was a project from last Nov so Ill have to dive back into it when I get a chance.

[Ivaylo Katev]

it should be already in the 5.1 nightlies

[kosso_olli]

Thank you, I just tested it. The glossiness parameter seems to work as expected, no more blurred clearcoats in 5.
I noticed the glossiness variation parameter, too. Can you please explain what it does?

EDIT: It seems it controls the glossiness falloff for grazing angles. Neat, this is exactly what I would have needed for one of the recent projects!
Is this also a value which is measured with the scans and thus set to a measured value upon loading? Because I have a matte car paint sample scanned a few weeks ago, where the glossiness variation parameter comes in at 0 after loading. Also, the glossiness is set to 0,82 after loading. But the appearance when rendered is much more matte, like a value of 0,5 for example.
That sample was somewhat altered for us to use in Next, so maybe that is the issue.

[Ivaylo Katev]

Hi Oliver,
yes, in the UI the glossy variation is also marked with * that means it comes with "measured" value from the material, with the note that we are still not able to measure it,and we have almost no materials with glossy variation. The few materials where we used this parameter were adjusted manually.
About the appearance - the vrscan's glossines is actually measured in different units, but in the user interface we convert it to VRay units to avoid additional confucing in the users. The conversion is made by a formula (i mean not by a table), and covers the entire range. The appearance is tested with the attached scene, you can try it with your material to check the result.
I should warn you that the glossy variation would produce slightly different result in VRay 5 compared to Next. The reason is the different way used in 5 to introduce the variation. In Next all the clear coat materials were assumed perfect mirrors,and the variation was decreasing the glossines when the observation angle gets near to frontal. In 5 the glossines can vary and is defined under frontal observation, the variation increases the glossiness when the observation angle is shallow. More precisely,the variation sets the angle where the glossiness growth becomes significant. Under "parallel to the surface" observarion it always gets 1.

[kosso_olli]

Thanks for the clarification. The glossiness parameters will be usefull for matte surfaces like carpaint or wood trims with matte clearcoat.