Tutorials on Quixel Megascans library to C4d/Corona workflow

[corriette]

Hi,

Does anybody know of good tutorials where I can properly learn importing content from the Quixel Megascans library into C4D/Corona?
I found only this one, but it's for Octane.
http://cgterminal.com/2017/06/09/cinema-4d-stunning-environment-megascans-octane-tutorial/

I find myself out of my league when trying to convert this workflow to C4D/Corona.
If anybody wants to have a look, skip right to 7:22, all the import-action is between 7:22 and 11.58

I'm particularly interested in how to deal with the glossiness channel in C4D/Corona. He talks about it from 10:55 to 11:35.

Any help is much appreciated.

Thanx.

[Eddoron]

Roughness is basically just inverted glossiness. IIRC you can download both types when you download something from Megascans.
For the Specular:
He's just mixing the specular map with a color and using a fall-off as the mask. The fall-off would be in this case the fresnel shader.

[ozwald]

It really takes a lot of tutorials to understand how Corona works, and users are not making mistakes.
It would be nice to have a forum or a website dedicated to crown tutorials for cinema 4d

[Eddoron]

I don't think so at all.
Corona is a lot more intuitive and artist-friendly than many other engines.  After all, that's how it was designed.
Arnold, for example, that would take some time to learn properly.
But if you know the fundamentals of CG, with Corona you won't bump into a steep learning curve.

There are official tutorials on youtube, the documentation and nothing beats learning by doing/trying.
But if you want some, go here:
https://corona-renderer.com/resources/tutorials

[TomG]

Yep, official tutorials are in our C4D playlist on our YouTube https://www.youtube.com/watch?v=kustKlQ6c0U&list=PLt4UrWcQaAX8O9JnSsAzKA_GxIU43yVAZ - naturally we haven't done too many of these while things are in development, as UI and features can change and we'd have to throw out the tutorials :) But now that things are getting more finalized, you can expect to see more as we go forward.

Also our helpdesk page covers a lot of topics - https://help.c4d.corona-renderer.com. Again, this is a section that will keep growing over time!

[corriette]

@Eddoron: Thanx for helping out.
I downloaded all of the maps available, so I could play around with them and I did know I needed to use the glossiness-map (I've ignored the roughness-map all together.)
Somehow I failed to realize that the "mix-trick" he uses, was in fact the fresnel-shader. So thanks for clearing that up.
One question though: does this mean I have to load the map into the fresnel-slot in Corona also, or would I just simply play around with values? (within the dielectrics range, I suppose.)
And lastly, what is the "normal vs vector 90 degrees"-setting he selects?

@TomG: I know you guys are waiting for everything to be more final before you record more tutorials and I think we're all eagerly awaiting those.
@Ozwald: Having said that, I did learn a lot from watching all tutorials that exist for Max and tried to convert it all back to C4D. Works for greater part.

[corriette]

Just come to realize that probably this "normal vs vector 90 degrees" IS what makes it a fresnel-shader.
(Please correct me if I'm wrong, I'm a newbie trying to learn here.)
Still the same question though: do I load the glossiness map into the fresnel-slot?

[Eddoron]

Yes, the IOR slider does what it should, the optional map slot is for maps. When you have a complex material that is composed of let's say water&oil.
Substance Painter can also output maps for that but I haven't painted in that channel yet.

The "normal vs 90 degrees settings" which he means is one of multiple settings in octane "normal vs eye ray", "normal vs 90°" and "normal vs 180°".
The first option behaves like the fresnel shader (and I also think he meant that one because it makes more sense, though I'd have to rewatch with sound), the others are at an angle to a (custom)vector and you can create a snow mask for a mountain etc. Those are all settings you can also find in the c4d fall-off shader, modify the vector with -1 to 1. 0(x),0(y),1(z) and camera dependant would behave similarly to the fresnel shader but take the whole object into account, not only up to the most grazing angle.

edith: the glossiness map comes into glossiness slot. He only mixed the specular material with a color node and the fall-off as the mask. The specular mix would go into the reflection slot in Corona.

[corriette]

Hey Eddoron, sorry for the late response.

Thanks for explaining that in detail, that makes so much more sense to me now.
Still learning about the whole PBR-thing.

I've been further playing around with the megascans-files, but this time the displacement is giving me trouble.
No matter what value I input, I can't seem to get it right.
At low values the result doesn't seem to budge (<1cm), higher values (>2cm) make the whole thing explode.
I've tried dividing the mesh further with an SDS-object, but that only seems to amount to rounder corners, which are not wanted, obviously.
Any thoughts on this?

Also, is it normal that the IAR needs to be stopped and restarted for every new value that I input in the displacement? Or would that be a bug?

[Eddoron]

Hi,
You don't need to divide objects in corona for displacement. One polygon is enough. The accuracy is set in the render settings either by size per pixel or per scene unit.
As I see, you're using the  32bit floating point displacement map. I'm not sure how corona handles those. I've been only using 16 bit here.
But Displacement is always scale dependent. If you have an object that is let's say 1cm in diameter, then the polys shouldn't be pushed out very far.
I have a link to a tutorial somewhere where you can find out what's the best method to apply the map you have. I'll post it as soon as I find it.
As a general rule of thumb, I start with ~1% of the diameter and adjust it then.(if the scale of the used map isn't already described somewhere.)
Another thing is to find out if the map was generated object centered- meaning 50% gray value is 0, pushing outwards -black=0, inwards-white 1 and you have to push inwards(rare).
Floating point maps can have negative numbers so that makes the thing a bit trickier.
Make also sure that you're using linear color space for the displacements. You can set it in a corona bitmap shader, for example.That way, you won't get an exponential rise in the displacement.

About the IR: It's still a new feature and some things don't display correctly or need a restart. Also note that when using pixels for the control of the displacement, then it will retain the quality of the started IR view.ie. if you started the IR with the object farther away and go closer with the camera, it won't get more detailed or if parts of the object were off-screen before, they might not be "subdivided" at all.


until I find the link:

https://coronarenderer.freshdesk.com/support/solutions/articles/5000515597-my-displacement-has-huge-spikes-or-is-invisible-

https://www.cggallery.com/tutorials/displacement/

[corriette]

Hi,

All great information.
Thank you.
The main problem was indeed the scale. I didn't scale things up upon importing, so that messed the whole thing up.
Once I had rescaled my project, I had a much better handle on the displacement.

FYI, the best results I got from putting the 32-bit map into a Corona-bitmap (so linear) - so that does work and I feel it works well.

About the IR: I'm perfectly fine with restarting it every time. It's just with my inexperience, I sometimes am unsure whether it is user-error or a development hick-up.
But I think it's great that we can use it already, so no complaints here. :)