HDRI Coordinates in C4DtoA

[Anonymous]

Hi there!
I'm testing the Arnold for C4D demo and I came across a rather weird issue with the Skydome reflections. I've rendered the same image in Vray, Corona, Physical and Arnold, and I keep getting an unexpected result with Arnold.

Here's the renders comparison of a simple chrome sphere and a sky or dome object in each render engine:

Arnold is the only renderer that shows me an inverted version of the Arnold Sky image, rotated 180º.
If I adjust the Arnold Sky coordinates to 90º, 180º, 0º and invert the Y scale it shows the same as the other render engines, but by default it shows me an inverted and rotated reflection.

I'm using this HDRI file from HDRI Haven:
https://hdrihaven.com/hdri/?c=studio&h=photo_studio_01

I've tested other HDRI files, from other sources like Grayscale Gorilla, but the results are the same.

I've also created an alternative setup in Arnold, with a basic sphere acting as a sky, with the same HDRI applied to it, which produced the same results as the other render engines.

I'm using the latlong coordinates in Arnold Sky, but the other options produce even worst results.

Am I missing something? Might this be related to the default Arnold sky coordinates?

Thanks!!

[lee_griggs]

Do you get the same issue with the skydome_light?

[peter.horvath6V6K3]

Hah, that's interesting. It must be like this for a long time (maybe day 1). I'm surprised that nobody else reported this so far. The difference must be coming from the coordinate system used by Arnold vs C4D, which is handled in other places, but not here it seems. I have to investigate to be sure, but definitely looks like a bug.

[Anonymous]

Thanks Peter!
Can you make a quick test and see if you get the same results??
Much appreciated.

[Anonymous]

Hi Lee. Thanks for helping out.

I get the exact same result with the Skydome light.

I tested in two different computers, a mac and a pc, and I get the same result.

Running out of ideas...

[peter.horvath6V6K3]

Yes, I did and I see the same.

[peter.horvath6V6K3]

This is now fixed in C4DtoA 3.3.0. Note that the Cinema 4D sky object flips the texture (which seems to be incorrect). There's a new Flip checkbox added to the Arnold Sky and skydome light in case you want to match the C4D Sky.

[Anonymous]

Perfect!!
Thanks for the quick update.

[Anonymous]

Getting the same issue on 3.3.0 while loading the scene from 3.2.1. The new flip checkbox doesn't work, only manual -90 rotation showed the correct result matching the original scene.

[peter.horvath6V6K3]

Following updates in C4DtoA 3.3.0, loading old scenes (prior 3.3.0) which contain skydome type Arnold Light objects (not an Arnold Sky object) have an issue with skydomes rendered rotated. It will be fixed in an upcoming bugfix release.