Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: mommus on 2014-11-28, 10:06:49

Title: black glass refraction?
Post by: mommus on 2014-11-28, 10:06:49

Hi guys,

   I've been rendering an interior scene of a barn conversion I'm designing.

   I've used a Corona sun for the external light with the sunlight shining through a large run of windows.

   There seems to be a strange dark area in the shadow/refracted sunlight cast on the floor - it resembles the shadow of a fir tree - but it isn't there when the refraction of the glass material is overridden (or when the glass is hidden). It's at the bottom left of the image.

   The glass material is a very simple standard setup with an IOR of 1.05

(http://i59.tinypic.com/f51rhk.jpg)

   Has anyone else had this issue?

Title: Re: black glass refraction?
Post by: maru on 2014-11-28, 10:37:49

It really does look like a tree. Do you have a tree object in your scene? Maybe it's hidden?

Title: Re: black glass refraction?
Post by: mommus on 2014-11-28, 10:50:28

Definitely no trees there

If I hide the glass, or tick Thin (no refraction) the artifact doesn't show up.

Title: Re: black glass refraction?
Post by: romullus on 2014-11-28, 11:27:35

Maybe there's some overlapping polygons?

If you hide everything except sun, glass and floor objects, does problem persists? If yes, could you upload scene with only those objects?

Title: Re: black glass refraction?
Post by: mommus on 2014-11-28, 11:54:06

Still happening if I isolate sun, floor and glass

also still happens whether Corona Sky is on or off.

I'm confused

Title: Re: black glass refraction?
Post by: mommus on 2014-11-28, 12:01:46

just looking at it now - it seems that the black area is actually the direct reflection of the sun - but inverted for some reason

if I remove everything but the sun and the floor, the sun itself is reflected in the floor, but for some reason when it is refracted through the glass, the direct reflections of the sun are black

unticking any of the boxes under 'Visibility' in the Corona sun dropdown seems to make no difference - replacing the glass texture with a new one, and replacing the glass geometry doesn't seem to help either

Title: Re: black glass refraction?
Post by: maru on 2014-11-28, 19:42:20

Can you upload the scene or similar with this effect? :)

Title: Re: black glass refraction?
Post by: drado226 on 2014-11-28, 23:04:24

i want to see this scene , you must upload floor map too, im very curious

Title: Re: black glass refraction?
Post by: mommus on 2014-11-30, 20:37:05

where should I upload the scene to?