New Corona Physical Material (PBR) playground!

[Feodor]

Hi,

Can you send over a scene for the second issue you described? I am unable to reproduce this crash/hang.

Cheers,

Rowan

It doesn't make sense to load the scene at all. Try creating a teapot object, with 64 segments, or a sphere of 200 segments, put the material and click the render button. This happens with highly polygonal objects

[rowmanns]

Hi,

Can you send over a scene for the second issue you described? I am unable to reproduce this crash/hang.

Cheers,

Rowan

It doesn't make sense to load the scene at all. Try creating a teapot object, with 64 segments, or a sphere of 200 segments, put the material and click the render button. This happens with highly polygonal objects

Hey,

Thanks for the info! I was missing the high polygon objects part. I will forward this to our devs.

Rowan

(Report ID=CRMAX-80)

[GeorgeK]

PS
please guys, pay attention to the implementation of coating, which we wrote about above. let it be possible for coating to smooth the surface, creating mirror-like glossy coat with displaying the height details of the surface lying below, as Bormax mentioned here

New material is really great! Thank you!

The Clearcoat layer is the thing I was missing for very long time, nice to get it now. Some idea came to my mind about it.
Now the Base bump affects the Clearcoat layer and Clearcoat bump gives possibility to Add bump to this layer. Would it be nice (if it's possible) to have kinda lock between Base bump and Clearcoat bump in order to imitate the bumpy surface covered by the polished transparent layer of lacquer? Something like on attached picture where I've created the geometry of the covering layer and assigned different material to the inner and covering surfaces.
According to this idea if the Lock is active Base bump affects the Coatlayer, if it's unlocked only Clearcoat layer's bump affects the Coat layer.

PPS
and maybe it is worth lowering the metalness map slot below the others, because now I habitually attach base color or diffuse to it as it is the first in the list :D

Thank you and Bormax for your input on this, I have passed all information to the devs.

(Report ID=CRMAX-85)

[n2graf]

I have seen that you have improved the BDRF single scattering problem that appears for maximum reflections with high roughtness, where all the 100x100 light should be reflected. Now it reflects much more light than before. Will it end up implementing a multiple scattering BDRF solution where all complete 100x100 of the light is reflected?

It would be nice if there was a numerical value for the amount of metalness because almost no material in reality is pure metal, there is always a film of rust or dust, and we would save time applying a corona color to obtain a gray value, if we could regulate the amount of metalness with a numerical value as an alternative to using a map.


Thanks!

[GeorgeK]

I have seen that you have improved the BDRF single scattering problem that appears for maximum reflections with high roughtness, where all the 100x100 light should be reflected. Now it reflects much more light than before. Will it end up implementing a multiple scattering BDRF solution where all complete 100x100 of the light is reflected?

It would be nice if there was a numerical value for the amount of metalness because almost no material in reality is pure metal, there is always a film of rust or dust, and we would save time applying a corona color to obtain a gray value, if we could regulate the amount of metalness with a numerical value as an alternative to using a map.


Thanks!

Hey, thanks for the feedback. I will get back to you on the first one, in regards to the second I have reported it to the dev-team for consideration.

(report id=CRMAX-120)

[marchik]

for some reason I now miss the opportunity to change the final level of reflections using a spinner or a BW map, sometimes it helps a lot in bringing the floor material to realism, now you have to create a composite map with two ior values :DDD

[maru]

for some reason I now miss the opportunity to change the final level of reflections using a spinner or a BW map, sometimes it helps a lot in bringing the floor material to realism, now you have to create a composite map with two ior values :DDD

Can you explain what exact property you would like to change?
With the new physical material, you should be following the metalness/roughness workflow. You can map metalness, roughness, and IOR.

[marchik]

for some reason I now miss the opportunity to change the final level of reflections using a spinner or a BW map, sometimes it helps a lot in bringing the floor material to realism, now you have to create a composite map with two ior values :DDD

Can you explain what exact property you would like to change?
With the new physical material, you should be following the metalness/roughness workflow. You can map metalness, roughness, and IOR.

Of course I understand that I should use a metallic / roughness workflow, there is no problem with that) and of course there is a direct relationship between roughness and the strength of reflections, the same as it was in legacy corona mtl

And despite this, there are some materials in which, to achieve better results, sometimes it is necessary to tweak the final strength of the reflections with spinner or B&W map, and its not very convenient to do this by mixing two linear ior values

as an example, lets take a flooring material, let's assume I use a generator from Poliigon and at the output, in addition to roughness, I will also get a specular level (pic1) but unfortunately now I can't use it directly but only as a mask when mixing two IORs, in fact it is not a big problem, except that mixing different IORs give a slightly different result from simply reducing the strength of reflections. e.g. in legacy mtl i used speclvl in reflection color slot with about 5-15% of opacity

[romullus]

as an example, lets take a flooring material, let's assume I use a generator from Poliigon and at the output, in addition to roughness, I will also get a specular level (pic1) but unfortunately now I can't use it directly but only as a mask when mixing two IORs, in fact it is not a big problem, except that mixing different IORs give a slightly different result from simply reducing the strength of reflections. e.g. in legacy mtl i used speclvl in reflection color slot with about 5-15% of opacity

I can't tell you how realistic those maps are - i suspect they are pretty arbitrary, but by mapping IOR instead of reflection level, you get at least physically more correct results, even if it requires more work to set-up.

[marchik]

I can't tell you how realistic those maps are - i suspect they are pretty arbitrary, but by mapping IOR instead of reflection level, you get at least physically more correct results, even if it requires more work to set-up.

exactly) no matter how realistic those maps are, my eye and little tweaks will make them look realistic)
and for my part, I'm just looking for a handy tool that will allow me to achieve this in less amount of time.

it would probably be a good idea to allow  mapping ior values ​​with rgb where  ​​1.0 is 0.0.0 and 3.0 is 255.255.255, in this case we can easily clamp our speclvl map values ​​to 0-128 and get reasonable results. Just my thoughts.

[n2graf]

I wanted to contribute some insights.

For metallic materials that accumulate a thin layer of dust, it is interesting to be able to map the metalness so that it has dielectric zones (non-metal), as the physicalmtl now allows. Previously we could do this by lowering the reflection and the diffuse color would appear. The problem now is that you are forced to make the reflection color the same as the diffuse color of the non-metal you are mixing, since there is only one slot for base color. It might be interesting that there is a slot for diffuse so you can separate the gold color for the reflection of the metal and the white color for the diffuse of the layer of dust or dirt. I know that it can usually be solved with the coronalayeredmtl but it is more laborious and makes sense for more complex cases. When you only want to add dust and dirt it would be useful to be able to do it from the physicalmtl itself since it has the option to map the metalness. Another option would be to place an identical color texture to the one we placed in metalness but that has the desired colors for the metal area and for the diffuse area of ​​dirt, but it is difficult to achieve textures like this or they would have to be generated by adding shaders previously, which complicates work, for this reason I think the most practical would be a slot for diffuse that will be activated only in the case that you want to map the metalness, as well as a spinner in metalness would be practical to be able to mix it numerically for little complex cases where we can save the step of putting a map. Thank you!

[maru]

it would probably be a good idea to allow  mapping ior values ​​with rgb where  ​​1.0 is 0.0.0 and 3.0 is 255.255.255, in this case we can easily clamp our speclvl map values ​​to 0-128 and get reasonable results. Just my thoughts.

Is this (screenshot attached) solution good enough for you, or would it be vital to have some kind of native Corona feature for this?

[maru]

For metallic materials that accumulate a thin layer of dust...

The issue is that metal and dust are two completely different materials. Layered Mtl would be definitely preferred here.
Maybe you could also use the built in Sheen layer? (you can specify its color, amount, and roughness so it's a bit like a layer of non-metal).

[rowmanns]

As always, you are on top!

But!
When testing the new Shader, I found two problems.
First: in a refractive material, when the minimum roughness value is set, the IOR changes significantly. Shown in the picture. Especially the picture becomes different when using glass with the Shell modifier
Second: if you set the roughness value to 0 in the Sheen layer, 3ds max 2021 will hang dead. (There must be a division by zero) :))

Second issue is fixed in the latest daily. Available here: https://forum.corona-renderer.com/index.php?topic=30876.msg180340#msg180340

Cheers.

[marchik]

it would probably be a good idea to allow  mapping ior values ​​with rgb where  ​​1.0 is 0.0.0 and 3.0 is 255.255.255, in this case we can easily clamp our speclvl map values ​​to 0-128 and get reasonable results. Just my thoughts.

Is this (screenshot attached) solution good enough for you, or would it be vital to have some kind of native Corona feature for this?

As I described, I am using this solution now, of course, this is not an "vital" feature, but just my suggestion to simplify the usage of the new shader, is that what you are aiming for in the end? convenience and realism) What I'm most worried about right now is the implementation of changing the bump effect on the clearcoat layer. Everything except the clearcoat layer works well overall, thx :D