Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] Bug Reporting => [Max] Resolved Bugs => Topic started by: Oltskul on 2013-02-08, 10:20:20

Title: Alpha leaks
Post by: Oltskul on 2013-02-08, 10:20:20

Hi i just remeberd, when i was rendering this immage, I have encountered some artifacts in transparency of exported image. Artifatcs are apparent in the "alarma light" on top of the model
(attachment). That middle part, where is supposed to be black axle is transparrent (later on i will upload the PNG with alpha and upload the scene)

In the render it looks OK, because I faked it with solit behind that.

http://forum.corona-renderer.com/index.php/topic,336.msg2983.html#msg2983

I will render larger detail when I will get to corona. I completely forgot to upload that scene yesterday. But it is possible that those artifacts are caused by "bad" geometry.
 

Title: Re: Alpha leaks
Post by: Oltskul on 2013-02-08, 19:22:46

the alpha leak - more obvious...

scene on sunday - aint got no time for that now :)

Title: Re: Alpha leaks
Post by: Polymax on 2013-02-09, 08:12:12

I checked the bug, well, again, everything is normal,  the alpha channel is correct.

Which version of renderer you are using?

Title: Re: Alpha leaks
Post by: Ondra on 2013-03-04, 19:46:42

Can you provide a sample scene for the problem? Because I don't see it ;)

Title: Re: Alpha leaks
Post by: Oltskul on 2013-03-04, 20:12:47

my build:
Defines:  LEGACY  STATS
Internal color space: CIE XYZ
Build timestamp: Jan 21 2013 03:04:05
Max version: 2013


scene: free of charge :) but you need to relink the corona proxy!

https://dl.dropbox.com/u/17434859/bagrik33-alfa02.zip

Title: Re: Alpha leaks
Post by: Ondra on 2013-03-04, 20:55:50

Do you have the original objects (not in proxy)? It is kinda hard to figure out what is even going on, and what objects exactly are there

Title: Re: Alpha leaks
Post by: Oltskul on 2013-03-04, 21:31:31

Quote from: Keymaster on 2013-03-04, 20:55:50

Do you have the original objects (not in proxy)? It is kinda hard to figure out what is even going on, and what objects exactly are there

last scene state before expoting model to proxy:

https://dl.dropbox.com/u/17434859/bagrik11.rar

model is from some Lego exporter :)

Title: Re: Alpha leaks
Post by: Ondra on 2013-03-13, 21:32:09

Mystery solved, there are self-intersections in the scene because it is poorly modelled, and there are double faces inside (one transparent plastic, other black). This can cause some rays to go through (and also creates interesting patterns). See attachements