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Re: [REQ] Shadow Catcher material...

Posted: Thu Feb 28, 2013 7:56 am
by Zom-B
OnoSendai wrote:
Zom-B wrote:This can be done with a background plate in the scene directly right?
No Physical mesh as background plate but rather something like a "Background Layer".
(with a few options to pan & zoom)
Checkout moofe: https://www.moofe.com/#/free
The free samples give a good overview of what that kind of material you get for such shots!

Also keep in mind that the shadow catcher needs to be a custom mesh, so irregular grounds can be used too :)

Re: [REQ] Shadow Catcher material...

Posted: Thu Feb 28, 2013 8:08 am
by galinette
Zom-B wrote:
OnoSendai wrote:
Zom-B wrote:This can be done with a background plate in the scene directly right?
No Physical mesh as background plate but rather something like a "Background Layer"
This would be exactly as an envmap, but instead of giving a spherical 360° image, it would be a partial image plus positionning parameters (direction of image center, rotation around direction, and FOV of image).

Re: [REQ] Shadow Catcher material...

Posted: Thu Feb 28, 2013 10:00 am
by OnoSendai
Did get the 'direct-composite' shadow catcher hack working. Only works in PT. It's quite fun to play with :)
Not sure if it will stay though.

Re: [REQ] Shadow Catcher material...

Posted: Thu Feb 28, 2013 10:14 am
by galinette
OnoSendai wrote:Did get the 'direct-composite' shadow catcher hack working. Only works in PT. It's quite fun to play with :)
Not sure if it will stay though.
What if there is a mirror beside the teapot, do you correctly see shadows in the mirror image?
Oh my god, a biased feature ;)

Re: [REQ] Shadow Catcher material...

Posted: Thu Feb 28, 2013 10:15 am
by OnoSendai
galinette wrote:
OnoSendai wrote:Did get the 'direct-composite' shadow catcher hack working. Only works in PT. It's quite fun to play with :)
Not sure if it will stay though.
What if there is a mirror beside the teapot, do you correctly see shadows in the mirror image?
Oh my god, a biased feature ;)
Probably not. As I said, it's a massive hack. But any kind of shadow-based compositing into an HDR image is.

Re: [REQ] Shadow Catcher material...

Posted: Thu Feb 28, 2013 10:15 am
by Zom-B
Awesome, I would love to see some bigger, more complex Object here :)
OnoSendai wrote:Not sure if it will stay though.
So what kind of direction you wanna go with it?

Re: [REQ] Shadow Catcher material...

Posted: Thu Feb 28, 2013 10:20 am
by OnoSendai
Zom-B wrote:Awesome, I would love to see some bigger, more complex Object here :)
OnoSendai wrote:Not sure if it will stay though.
So what kind of direction you wanna go with it?
Well, there are a lot of things that would be nice:

* Quick and interactive compositing into an HDR environment. (this is what the current hack does)
* Correct (or as correct as possible) shadows
* be able to use more advanced render modes like bidir.
* Avoid precomputation / pre-pass if possible

I'm not sure if all of these are possible at the same time :)

Re: [REQ] Shadow Catcher material...

Posted: Thu Feb 28, 2013 10:21 am
by OnoSendai
quick car render

Re: [REQ] Shadow Catcher material...

Posted: Thu Feb 28, 2013 10:30 am
by Zom-B
Looks somehow... not dark enough on the ground under the car, but maybe there are relevant Lights in the scene to bright it up.
Or does maybe the bottom of the car reflects light from the bottom of the HDRI and lightens up the shadow by doing so?

Re: [REQ] Shadow Catcher material...

Posted: Thu Feb 28, 2013 10:34 am
by OnoSendai
the shadows could be quite wrong.

Continuing with the 'American muscle cars in small German city streets' theme:

[REQ] Shadow Catcher material...

Posted: Thu Feb 28, 2013 8:11 pm
by zeitmeister
Hell yeah, gettin close!!
Shadows should really be darker.
Two ways sound really like the perfect way:
- The realistic shadow pass
- the nasty hack shadow catcher material

This will help artists tremendeously for quick compositing or product visualisation; even in previz state.

How did you light this last scene?

May there be an option that is controllable by the user? Like a shadow depth value slider or something?

Re: [REQ] Shadow Catcher material...

Posted: Thu Feb 28, 2013 11:20 pm
by CTZn
zeitmeister wrote:Shadows should really be darker.
Should they really that much ?

I'm not saying that their intensity is accurate because it was explained that this was not guaranteed, but the image is like that really, rather overburned.

look where the two shadows meet under the car; that looks nearly correct to me in this context :)

I think that the tires albedo do not reflect the complexion of a real tire car and that this is introducing a perceptive bias.

Re: [REQ] Shadow Catcher material...

Posted: Thu Feb 28, 2013 11:32 pm
by CTZn
CTZn wrote:look where the two shadows meet under the car; that looks nearly correct to me in this context :)
You'll get my point if you compare them with the shadows of the pipe on the left wall.

Re: [REQ] Shadow Catcher material...

Posted: Thu Feb 28, 2013 11:34 pm
by Zom-B
Simply render the scene with the shadow catcher as usual mesh, and compare the shadows :)

[REQ] Shadow Catcher material...

Posted: Fri Mar 01, 2013 4:02 am
by zeitmeister
Anyway,
very very cool!!!
Her damit! :-)