Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: spoudastis on 2015-06-12, 22:13:07

Title: Backplate display obscured by HDRI
Post by: spoudastis on 2015-06-12, 22:13:07

Hi,

Im new to corona and have been testing it to se whether I will make the switch over from vray (looks likely).  An issue I am running into is that when I use a PG HDRI in the environment slot there is a very obvious band where the horizon line is (normal).  However usually I put in a backplate so that this horizon line does not appear in reflections etc.  when I put in a backplate in this scene either on a light material or just on a standard material, I am still getting the horizon band with the backplate image and the rest of the image is obscured.  its like in photoshop when the mode is set to multiply.  is there a reason the backplate image is not being displayed?

Thanks in advance for any help.

Title: Re: Backplate display obscured by HDRI
Post by: Ludvik Koutny on 2015-06-13, 09:35:35

Are you using LightMTL with emit light option disabled?

Title: Re: Backplate display obscured by HDRI
Post by: spoudastis on 2015-06-13, 17:22:51

I have tried with a corona light material with both the light emitting and not.  I'm totally stumped.

Title: Re: Backplate display obscured by HDRI
Post by: Ludvik Koutny on 2015-06-13, 20:44:29

So it's still happening even with Emit light ON? And what about CoronaMTL with self illumination?

Title: Re: Backplate display obscured by HDRI
Post by: maru on 2015-06-13, 22:00:08

Haven't you disabled the "cast shadows" option for the backplate in object properties?

Title: Re: Backplate display obscured by HDRI
Post by: spoudastis on 2015-06-13, 22:36:30

Hi Maru,

Yes I have disabled cast and receive shadows.

Title: Re: Backplate display obscured by HDRI
Post by: Ludvik Koutny on 2015-06-14, 08:59:24

Quote from: spoudastis on 2015-06-13, 22:36:30

Hi Maru,

Yes I have disabled cast and receive shadows.

Yes, then that is part of the problem. Enable shadows back on ;)

Disabling Emit light in LightMTL will disable LightMTL's visibility to GI, therefore also shadows. But it's different to disabling shadows in objects properties, which works in unpredictable way.

The problem here that LightMTL with emit light off works also in unpredictable way, even with shadows enabled in object properties. (I hope it will FINALLY get fixed so i don't have to give this awkward explanation to everyone everytime :) ) I would therefore suggest you use CoronaMTL with self illumination plugged in rayswitchMTL with GI slot left empty.

Title: Re: Backplate display obscured by HDRI
Post by: spoudastis on 2015-06-14, 09:27:13

Thank you rawalanche for this explanation. I am on holiday for a week, but when I get back I'll give this a try and let you know how it goes.  Thanks again!

Title: Re: Backplate display obscured by HDRI
Post by: maru on 2015-06-14, 10:24:29

Here are Rawa's advices and examples in a more user-friendly form (hopefully :) ):
https://coronarenderer.freshdesk.com/support/solutions/articles/5000516723
https://coronarenderer.freshdesk.com/support/solutions/articles/5000515605

Title: Re: Backplate display obscured by HDRI
Post by: spoudastis on 2015-06-14, 17:39:53

Perfect!! Thanks Maru.