Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] General Discussion => Topic started by: cecofuli on 2015-06-11, 17:20:20

Title: Opacity performance - LOW!
Post by: cecofuli on 2015-06-11, 17:20:20

Hello guy,

we know, opacity is a very "killer render time" beast!
I wanted to see if there is some boost with the new Coronabitmap
Unfortunately no. But I noticed that, with opacity OFF, I can have a 2.5X boost! WOW!
Ondra, maybe can you improve something? Like in VRay (http://docs.chaosgroup.com/display/VRAY3/VRayMtl#VRayMtl-Example:Opacitymodeparameter)?


Thanks!

(http://www.francescolegrenzi.com/Temp/Corona/0063_Opacity.jpg)

Title: Re: Opacity performance - LOW!
Post by: romullus on 2015-06-11, 17:43:45

Comparing opacity vs no opacity in Corona and filtered opacity vs non filtered opacity in Vray isn't very fair.

Title: Re: Opacity performance - LOW!
Post by: cecofuli on 2015-06-11, 17:47:51

Yes, but for static rendering, I would like to get the lower rendering time possible. If non filtered can help, why not?
I tried with CoronaBitmap to change filtering blur and interpolation. No differences.

Title: Re: Opacity performance - LOW!
Post by: Ludvik Koutny on 2015-06-11, 18:13:27

Corona disables filtering for all opacity maps by default, so there is not much more to gain there.

It's not much of a surprise that opacity maps (especially as fine as conifer needles) will reduce performance of raytracer. Compare rendertimes of material with opacity vs material without opacity on same scene in Vray, and you will get same, if not bigger slowdown.

Title: Re: Opacity performance - LOW!
Post by: dfcorona on 2015-06-11, 18:33:50

Vray has the new Clip Map Opacity to render really fast! Maybe corona can come up with something like that.

Title: Re: Opacity performance - LOW!
Post by: cecofuli on 2015-06-11, 18:36:38

I know, but, maybe, as VRay does, we can reduce rendering time in such situations. 2.5X is very much!

Title: Re: Opacity performance - LOW!
Post by: Ludvik Koutny on 2015-06-11, 19:28:33

Doing these two things in opacity map will give you equivalent of Vray's clip mode for pretty much any 3ds Max renderer.

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=8451.0;attach=32700)

Title: Re: Opacity performance - LOW!
Post by: romullus on 2015-06-11, 19:56:40

Alternativelly you can make action in photoshop to resave image in indexed color mode, run all your opacity maps through it and forget all headaches with opacity once and for all :]

Title: Re: Opacity performance - LOW!
Post by: romullus on 2015-06-11, 20:49:02

Did quick non scientific comparison with Mental Ray.

MR
no opacity - 67 s
opacity - 202 s (x3)
opacity + translucency - 1063 s (x16)

Corona
no opacity - 54 s
opacity - 84 s (x1.6)
opacity + translucency - 96 s (x1.8)

So we have nothing to complaint about ;]

Title: Re: Opacity performance - LOW!
Post by: cecofuli on 2015-06-11, 21:14:15

So, it's a ray-tracer "problem". Nothing to do...  =) good to know, sadly ^___^