[Kevron]

Hi,

All I want is to output a shadow pass for 350 frames. Scene is only lit with Sun and physical sky.

It is basically a character standing on a chair. I want her shadow that the sun produces at the floor.

I am able to just render a shadow pass, but estimated time to SL 14 is 2 hours. So I reckon there is a lot to gain in optimization.

Only two materials in scene (white where the "shadow" is checked, and plain white for the character)
No motion blur, no displacement, no caustics etc..


Any tips to get this blazingly fast?



Cheers,
Tor M

[Mihai]

But is it an interior scene? Make sure that you still don't use fully white materials, even when rendering only a shadow pass. The pass takes into account the full GI lighting of the scene so having a 255 white reflective material will not give good results and probably take longer to render.

What resolution are you rendering at? Check if the shadow pass isn't clean enough already at a lower SL. Difference between SL 12 and 14 can be 30 min or so, and 2 hours.

[Kevron]

I´ll send you the scene via PM, maybe I could learn a thing or two.
No whites above 220.

Thanks!

[Mihai]

Well there is a strange thing in your setup in that the floor you want the shadow from is the same object as the bookshelf behind with all those books. And this whole object is also set to hide from GI. So you get some weird calculations of a sort of shadow pass that also looks "through" everything. It becomes inefficient because of all those books/bookshelf set to hidden from GI.

If you just want the shadow of the character on the floor, separate the floor and make only that a shadow catcher, and also hide the bookshelf completely. Then it's about 24x faster (and you don't need to hide the floor-only shadow catcher from GI):

[Kevron]

Hi, I think I also would like to catch her shadow on the books + shelf.

Any tips on optimizing that?

Thanks for looking into it