COSMOS assets materials mostly wrong.

[frv]

Thanks Tom,
I noticed though that these materials with very low IOR's look like crap. Weird is that some assets are converted with these low IOR's and others not.  I had never seen any help manuals or references on how to work with Coronamaterials where the practise is to lower IOR values to 1 or less  to obtain realistic results for 3D people, trees and so on.

I have most Maxtree corona assets and I have never seen any with these low IOR's other than those from Chaos Cosmos. Apparently Chaos does not use the Corona set up provided by Maxtree but converts the Vray ones. When I export Vectorworks files to C4D I notice that IOR's values are wrongly converted from C4D standard to Corona PB with IOr's 1 or less. The converter is broken for IOR values and reflectivity. Many of the Chaos 3D people assets are glossy like glass statues and do not look "okay" at all.
I use Cosmos as little as possible and only to convert assets in to the C4D asset browser to make sure I don't get a project rendered out with unexpected results.

[davetwo]

I too think there should be a fundamental look at how the corona assets are being created for the COSMOS asset browser. They often feel like automatic conversions without the level of care and oversight that I'd like.

[frv]

This is what the people look like straight from Cosmos.

The third from the left is Alexei and has a texture, roughness and bump map and a IOR of 1.54 and looks okay.

The zombies are:
Janna has maps for texture, glossiness, edge color and bump and a IOR of 2 and looks unrealistically bright.
Zeef has to live with just a texture map and looks unrealistically oversaturated.
Kaden has a texture, roughness and bump map and an IOR of 1.054 and looks unrealistically dark.

[TomG]

Do note that there are no "Corona assets" in the Cosmos browser - they are universal assets, created once, then used everywhere. Unfortunately they are not all as physically correct in their set up as Corona materials are, as noted earlier some have a "reflection color" which is used to dampen the result which can only be calculated in Corona as a change to the IOR as we (correctly) don't have the concept of reflection color. The material conversion done to get things in to Corona is also universal, and not asset specific, so we have to apply the same rules to every object in translating its materials into Corona.

The only possibility I can think of there would be to have the original materials edited to not use something like reflection color and just use IOR, making the materials more physically correct, and done in such a way that when we read them they would arrive in a better state  - and that would be a request to be sent in via ticket to the Cosmos team, as it involves changing the models at source. Thanks!

[frv]

Thanks Tom for your kind replies.

[davetwo]

Thanks for taking the time to reply Tom. I understand that they are Chaos  and not 'corona' assets. But as they are the only material and asset library that ships with Corona since the native library was discontinued - I really feel that they should be adapted for use in Corona properly.

[TomG]

I wouldn't disagree, I do think it would be worth a ticket (from users, to emphasize the importance of this) to request the source materials be reworked to be more readily compatible with all render engines. You can explain the problem being the use of Reflectance Color to "dampen" reflection strength without modifying the IOR, where Corona has to modify the base IOR as we (physically correctly) don't have reflection color - so if source materials were modified to simply use IOR with reflection color white, they should translate better. Perhaps better yet it can be a feature suggestion on the Cosmos board, as then it can be suggested once and then voted for :) https://chaoscosmos.ideas.aha.io/ for the portal, and if anyone does post a request, you can let us know here as then those interested can vote for it.

[davetwo]

I've added a 'idea' to the portal.

After downloading a coloured glass material form cosmos the other day I noticed that volumetrics weren't even turned on, so it was actually colourless. Such a simple problem that should be picked up by quality control.