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Can V-ray emulate Corona reflections?
show user profile  LowSpeaker
Hello everyone, I'm a Corona user, i fiddled a little with V-ray but never really used it.
I was given a task of changing several assets from Corona to V-ray, being a Metal ray user (before Corona) I thought it will be a fairly simple task since material creation in those two is quite similar. But, I can't seem to get anywhere near Coronas results.

I hope someone here knows both Corona and V-ray, but in short Corona uses PBR materials and for reflection tweaking you just leave reflection value at one, IOR at ~1.6, and just change glossiness value (for 95% of materials).

So first I tried doing the same thing as in Corona, changing just glossiness value:


As you can see, this got me nowhere.

Then I tried changing the reflection values as well, since that is "the old way", just like it was in Corona before PBR and as is in Mental ray, balancing glossiness, IOR and reflections values.

But, that also didn't work. While Corona at glossiness 0.5 gets blurred but defined reflections, V-ray just creates one big blotch.


Then I tried with a map, in Corona plugged just in glossiness, in V-ray first only reflections, then only glossiness, then both. Again, no go.


Tried the same thing again but run the map through Mix map to accentuate the problem


Things get even worse when i drop down IOR to a more realistic value (still higher then needed for wood to have clear reflections). Corona is pretty straight forward, "raised" parts of wood are reflective, "lowered" ones are not.
V-ray, uniform washed out reflections.


I also tried plugging the diffuse map into reflection (not Mix map as above), but that just changed reflections a bit, not solving the problem.

I know these are two different rendering engines, I'm not looking for an exact same results, just something similar enough.

Thanks in advance!
read 153 times
9/4/2017 7:29:03 PM (last edit: 9/4/2017 7:29:03 PM)
show user profile  Bolteon
Chaosgroup now owns both, so they'll be getting more similar in the future.


In the mean time, it's mainly the difference in BRDF selection and knowing that 0 glossiness in V-Ray is a no no.

-Marko Mandaric



read 151 times
9/4/2017 7:48:02 PM (last edit: 9/4/2017 7:48:02 PM)
show user profile  FX
I haven't touched Corona in a while but have you tried the conversion script ?

http://corona-renderer.com/forum/index.php?topic=6375.msg51713#msg51713

read 139 times
9/4/2017 11:00:07 PM (last edit: 9/4/2017 11:00:07 PM)
show user profile  LowSpeaker
@Bolteon:
Yea, I was able to get somewhat close by balancing reflection, glossiness and IOR. I wouldn't even call it "close", but hey...
The thing is, I have quite a few of the materials to convert. I was hoping there would be some "formula", if in Corona glossiness is X, in Vray set reflection and glossiness to Y. "Manual" conversion will take some time and lot's of re-rendering.

@FX:
Yes I did, unfortunately this is a pretty old script, before Corona went GGX and PBR, so it no longer works properly.
read 121 times
9/5/2017 4:30:39 PM (last edit: 9/5/2017 4:30:39 PM)
show user profile  Bolteon
Post it up on the Chaosgroup forums, Vlado is always happy to help out when there's merit to a question regarding "why can't I do this?" in V-Ray.

-Marko Mandaric



read 108 times
9/6/2017 4:29:03 AM (last edit: 9/6/2017 4:29:03 AM)
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