Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] Bug Reporting => [Max] Resolved Bugs => Topic started by: marchik on 2019-06-11, 16:48:07

Title: Very slow render of metals with glossiness 0.7-0.99
Post by: marchik on 2019-06-11, 16:48:07

I have noticed this issue after installing Corona 4 Release version, when i create simple metal (or mirror-like) material with ior 23-999 and glossiness between 0.7-0.99, rendering models with material applied becomes weird and slow, its happens both for IR and Production rendering in all complex scenes no matter of lighting, with hdri or simple Coronalights, caustics on and off, with new lightsolver on/off, the only thing that helped me is a fresh scene with one sphere in it) then it is rendered well.

I attach screenshots of comparison between the 5th and 25th pass
I want to upload GIF but it is too big)

3ds max 2018
Windows 10
Xeon E5-2683 v3
32 GB RAM

Title: Re: Very slow render of metals with glossiness 0.7-0.99
Post by: maru on 2019-06-12, 14:40:14

This definitely doesn't look correct, but we will need more details to understand it (for example - how exactly is the bg/enviro loaded?)
Could you send a sample scene here or contact us about this at https://coronarenderer.freshdesk.com/support/tickets/new ?
Thanks a lot!

Title: Re: Very slow render of metals with glossiness 0.7-0.99
Post by: marchik on 2019-06-27, 20:16:34

I've deleted all objects except one with materials causing this bug, metal with glossy ~ 0.90 and glass with refr glossy ~0.95
https://www.dropbox.com/s/0v452jdhvwdt729/Bugrep.zip?dl=0
enviro hdri loaded as CoronaBitmap in "Single map" slot in scene settings but it is the same for multiple maps connected to LightMix and for maps in 3ds max environment tab

Title: Re: Very slow render of metals with glossiness 0.7-0.99
Post by: maru on 2019-07-05, 11:40:18

Thanks, looking into this.

Title: Re: Very slow render of metals with glossiness 0.7-0.99
Post by: maru on 2019-07-05, 11:48:00

You have various development/experimental settings changed in your scene.
Please:
- Do not touch the development/experimental stuff rollout until you are sure you know what you are doing
- Reset your render settings - this solves the issue

Attaching before and after images. Before is rendered in 2 minutes. After is rendered in 10 seconds.

Title: Re: Very slow render of metals with glossiness 0.7-0.99
Post by: marchik on 2019-07-07, 11:36:47

thx guys, maybe i change smth accidentially when scrolling down through settings) my bad