ShadowCatcher questions

[SHORT CUTS]

I need some help again, please bare with me since we are not using corona on daily basis....yet ;)

[1] Is it normal behaviour that once you put a ShadowCatcherMtl in your scene the rendertimes increases quite a bit? In my tests it varies from more than 200% to even 3000% in some cases (somehow my simple test scene took way longer then the scene i am working with: without the shadowcatcher it took 5 sec. with the shadowcatcher applied to the groundplane it took up to 3:24 minutes. My working scene reached a noise threshold of 3.5% after 115 passes in 4:59 minutes, while the same scene with the shadowcatcher aplied to the ground took 580 passes to reach the noise threshold in 12:41 minutes.)

[2] I am also struggling with the shadow and reflection intensity when using the the ShadowCatcher, the shadow and reflection are way too strong when compositing the rendering on a  background oppse to my reference rendering. I am not sure what i am missing here to get a better match....to better illustrate what i am talking about see this screenshot: http://prntscr.com/godxd6

thanks in advance and have a nice weekend :)

[lmikkelb]

1: Are you using the compositing mode in shadow-catcher? If so, it is slower for some reason, i guess you will have to wait for the devs to fix this/ develop it more,  seems like the black background is taking a lot of the resources. :D I have no clue.
maybe try one of the other modes, might be faster.

2: I think the solution to this is to render everything with passes, comp it together with masks, and change the reflection intensity in post. That way you will have a lot more control. U can also render only the reflection pass of the ground , as one separate pass alone.

I think u can also use the AO with directionality to get the shadows.

[Juraj]

There must be something wrong with the compositing mode but it's been like that since beginning, multiple threads were wrote about it, but so far no fix.

It's 10-100 times slower, it's crazy. Unusable mode : /

[Nejc Kilar]

I also haven't figured out why the render times go nuts when using the "for compositing" mode. What I normally do I render the shadows separately aka one beauty render on white and then another with "for compositing" just to get the shadows.

I'd really like to hear if thats the intended behavior or if there are any improvements incoming.

[romullus]

IIRC Ondra said that the fix is very hard and would require core rewrite or something along those lines. But i still hope it will be fixed eventually. Clean shadowcatcher in for compositing mode, would significantly improve my workflow.

[sprayer]

i think many people want speedup of shadowcather