OTOY Forums

Background Composite again!

And it seems I really can´t figure it out.

Still I want the following, putting an object into a cameraprojected scene:

Pass A: "Sphere only" with alpha
Pass B: Shadow only (only of the sphere)
Pass C: Reflection only (only of the sphere)

Desired result after comping: Reflecting object sitting inside a scene with a reflecting ground and correct shadows.




Issue 1: I acted after that: https://www.youtube.com/watch?v=7eCzaZzqZZY (put speed to .25)
In the "main" liveviewer pass it doesnt show me the floor and the left wall (similar to the video) but instead the entire background + the sphere without shadows in the liveviewer. No way to judge how it´s sitting in the scene.

Issue 2: Because I put a cube as a wall to the left it should block any hard shadows. and it does so on the sphere itself. BUT on the Floor object the shadow is still hard.

Just some minutes ago Issue 1 wasn´t occurrent for some reason. I´m not sure if it´s a refresh issue.
However, then I had another thing,
Issue 3: also the left wall was also reflecting in the Layer´s reflection pass, thus adding to the original room reflections after comping which also isn´t desired.

Simple Scenefile and renderpass outputs attached. "BG" Shader is in glossy mode to make it reflect the sphere.

Why do I have this issues?
Composite Background should be such a easy task...

You can use the BG material as diffuse material and enable Shadow catcher under Common. Problem is you cannot get reflections with it so you might need another rendering for reflections and grap them from multipass layer

I agree stuff ike this should be waaay easier since it is everyday work for us.

Hi Ceen,

thank you so far.

But shouldn´t it at least block out the hard sunlight and be creating a soft shadow? I´m pretty sure it should. And again it seems like a pretty arbitrary behavior to me.


Of course I could also just render an objectpass for the sphere only.

But also: I had cases where it looked in the liveviewer just as expected: No Background but a sphere with cameraprojected floor and a shadow. I have no clue why it looks different (also different to the linked video) now.

Also: as mentioned there is the is still the annoying "Issue 3"