Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: karklinskarlis1993 on 2018-02-11, 12:10:39

Title: does curtains need to have thickness?
Post by: karklinskarlis1993 on 2018-02-11, 12:10:39

hello there,

i wish there was a spam part of this forum as my question is really straight forwarded.
i made a few tests and onesided cloth looked imho a bit better than solid twosided. (onesided allowed more light to penetrate)

can anybody give me a fast hint what to do and how they do it. i am bit confused. its first time ever i use transparent curtains...

(http://www.bildites.lv/images/mmbez5v2/103090/original.png)

(http://www.bildites.lv/images/363swev8/103091/original.png)

TWO SIDED <----> ONE SIDED

Title: Re: does curtains need to have thickness?
Post by: maru on 2018-02-12, 13:38:55

You can use translucency on geometry with and without thickness. The results will be slightly different. Translucency is basically simulating very thin layer which scatters light.

With just one face on it's way, light will hit the surface, scatter inside of the very thin layer, and then pass to the other side.
With two faces, this will happen in two "layers", so the result will be probably a bit more "blurry", and less bright.

If you imagine a sharp shadow cast on such surface, with just one face, the shadow will be still sharp on the other side (imagine a sheet of paper). With two faces, it will get more blurry on the other side (imagine two sheets of paper, one placed behind each other).

Update: added a simple test to back up my theory. ;)

Title: Re: does curtains need to have thickness?
Post by: karklinskarlis1993 on 2018-02-12, 18:09:26

thanks for respond
so basically you can do it onesided way and dont get any weird artefacts coming from that am i right?
my aim is realism and in the same time ability to more light coming in as corresponding room has low amount of windows

Title: Re: does curtains need to have thickness?
Post by: maru on 2018-02-13, 11:32:52

Quote from: karklinskarlis1993 on 2018-02-12, 18:09:26

so basically you can do it onesided way and dont get any weird artefacts coming from that am i right?

Yes, there won't be any artifacts, as translucency is designed exactly for cases like this.

Quote

my aim is realism and in the same time ability to more light coming in as corresponding room has low amount of windows

Using curtains with no thickness will definitely not add realism, as there are no objects with no thickness in real life, so if you would like to have curtains with thickness, and bright interior at the same time, you can use the rayswitch material or map. For example you can use opacity-mapped material for the GI, and translucency for direct visibility: https://coronarenderer.freshdesk.com/support/solutions/articles/5000529341

Title: Re: does curtains need to have thickness?
Post by: karklinskarlis1993 on 2018-02-13, 16:38:56

got you. thanks a lot for your time, its much clearer now!