Another "how do you do it?" question

Tue Mar 04, 2014 2:01 pm

Ok all you gurus....

I have a background picture...say a beach. In the scene is Vicky. How do you get Vickie's shadow to appear as if its falling onto the sand...in the Octane render window and without merging alphachannels in Photoshop?

Thanks
Sam

Tue Mar 04, 2014 3:19 pm

Havent dabbled with it, but I guess you'd put "Vicky" onto a plane so a shadow can be cast and then get that plane to be transparent with only shadows remaining .... can't interact realisstically with things in the foto of course.

Tue Mar 04, 2014 3:22 pm

Havent dabbled with it, but I guess you'd put "Vicky" onto a plane so a shadow can be cast and then get that plane to be transparent with only shadows remaining .... can't interact realisstically with things in the foto of course. Google for poser and shadow catcher .. should give you something.

Tue Mar 04, 2014 3:30 pm

voon wrote:Havent dabbled with it, but I guess you'd put "Vicky" onto a plane so a shadow can be cast and then get that plane to be transparent with only shadows remaining .... can't interact realisstically with things in the foto of course. Google for poser and shadow catcher .. should give you something.

Yeah, the "surface" would have to be pretty flat...no steps or big mounds or anything like that.

Matter of fact, I think I remember two checkboxes on the parent object (ie., ground)...visible in camera and another for shadow visibility (or something to that effect). That may be the ticket!

I'll have to play when I get off work later.

Fri Mar 07, 2014 5:39 am

Set the plane to diffuse and enable "matte", this will turn it into a transparent shadow catcher.

You may need to enable alphachannel as well and merge it with the background pic in postwork.

Sat Mar 08, 2014 1:24 pm

I presume that the background plate you're trying to drop the shadow onto doesn't have a flat ground surface (sand).
By adding a flat ground plane as a shadow catcher - however - your shadow would become just that - flat.

If you want the shadow to follow the pattern of the sand you could render the image in Octane with an alpha channel and then drop the shadow later manually by using the 3D lighting option in Photoshop. That way you would have more control over the shadows hue and displacement as you would have by rendering it like my foreposters mentioned it.

Just my two cents...