Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: 16925 on 2016-08-25, 05:35:42

Title: Direct visibility override & thin glass
Post by: 16925 on 2016-08-25, 05:35:42
Please tell me if it's a bug or I don't know what I'm doing. Scene lighting is HDR image. CoronaBitmap is assigned as a direct visibility override.

On the right window I got total of 5 polygons with thin glass CoronaMtl located between camera and outside view: 1 window and 2 separators. On the left window I got total of 3 polygons with thin glass CoronaMtl located between camera and outside view of left window: 1 window and 1 separator. Each separator has 2 polygons of thin glass because of it's thickness (Multi/Sub-Object with solid glass on edges and thin glass on main planes).

My direct visibility override is cut and just bottom part is visible in the right window (that part is black in HDR). Once I remove any of separators (2 thin glass planes) I get it as it should be.

If I make all separators CoronaMtl (not Multi/Sub-Object) with thin glass it doesn't help: direct visibility override just disappears and only HDR image becomes visible through windows.
Title: Re: Direct visibility override & thin glass
Post by: romullus on 2016-08-25, 09:49:07
I hardly understand your description, but try this - activate refraction override and instantiate map from direct override over there. See if that solves your problem.

And yeah, solid glass in multi-subobject material will give wrong results in Corona. This is known bug and hopefully will be fixed in upcoming release.
Title: Re: Direct visibility override & thin glass
Post by: 16925 on 2016-08-25, 18:20:57
I hardly understand your description, but try this - activate refraction override and instantiate map from direct override over there. See if that solves your problem.

And yeah, solid glass in multi-subobject material will give wrong results in Corona. This is known bug and hopefully will be fixed in upcoming release.
Excuse me if my explanation was too long. In short, I don't get it why left window background is fine and right window background is cut off. Both windows are exactly instanced and between both of them and camera are instanced very same thin glasses. I doubt it's by design.
Title: Re: Direct visibility override & thin glass
Post by: romullus on 2016-08-25, 19:28:19
Can you upload simplified scene for inspection? You can strip anything that's not neccessary for this bug to appear.
Title: Re: Direct visibility override & thin glass
Post by: PROH on 2016-08-25, 20:08:47
Hi. There's another bug report regarding glass that might relate to this:
https://forum.corona-renderer.com/index.php/topic,12589.0.html

Besides that, the "light change" you're talking about might indicate that your background plane is set up wrong.

Hope it helps
Title: Re: Direct visibility override & thin glass
Post by: 16925 on 2016-08-25, 20:20:19
I double-checked with different images for direct visibility override and scene lighting. It works a little less obvious but still kinda funky. In my first post it probably has to do with reflection of HDR (that is very light) cutting the backplate when there's extra thin glass... Well I still encourage you to have a look if it's supposed to be this way.
Title: Re: Direct visibility override & thin glass
Post by: romullus on 2016-08-25, 20:56:01
Unfortunatelly i can't open it - file was created in newer version. Mine is max 2016.
Title: Re: Direct visibility override & thin glass
Post by: TomG on 2016-08-25, 21:15:31
2016 version attached
Title: Re: Direct visibility override & thin glass
Post by: TomG on 2016-08-25, 21:28:56
If I open and render the scene as sent with no changes, I get the image attached, and everything looks ok I believe? This is Max 2017, Corona 1.4. All objects are set to be visible when I checked how the scene is set up, with everything listed as a separator being visible. Is this different from your result rendering with the scene as sent? Or is there something I need to change in order to see the problem where the image outside gets cut off?

Thanks!
   Tom

Title: Re: Direct visibility override & thin glass
Post by: PROH on 2016-08-25, 21:48:05
OK. This makes some sense. The "cutoff" is actually overexposed double reflections.
Title: Re: Direct visibility override & thin glass
Post by: 16925 on 2016-08-25, 22:10:16
Yes that's the same result as mine.