Compositing Background with Alpha? Correct Shadows!

[Jahe]

Hello,

what I want to archieve is quite simple:

Comping a reflection object into an lmage via camprojected geometry, thus having correct reflections in the mentioned object AND THEN the object only with an alphachannel PLUS a shadow pass PLUS a reflection pass - so when slapcomped the object sits in the image nicely.

but... HOW? There are some threads but they somehow don´t answer this issue.

What I want to archieve can be seen here at around 06:04 (better change the speed to 0.25 ):
https://www.youtube.com/watch?v=7eCzaZzqZZY

This tutorial from 2016 uses the checkbox "Shadow" in the "Render Layer" Dropdown. But that checkbox seems to be gone now so I can´t figure out how to render out a white shadowpass with dark shadows in it.

Can anybody help?
Thank you!

[niestudio]

What version are you using? That checkbox should still be there.
Can you post a screenshot of your settings if you don't see it?

[Jahe]

I´m using V4.02.1-R3 in C4D R20 right now.

Screenshots attached.

[bepeg4d]

Hi,
please upgrade to 4.04-R2.
Now the Shadows pass in Render Layer is called Black Shadows:

ciao Beppe

[Jahe]

Hi bepeg4d,
I have that "black shadow" checkbox as well (as seen in my screenshot).

But it doesn´t give me out a white render with black shadows.

Also: there was used to be a "black shadow" and a "shadows" checkbox in the Render Layer field... if one is gone now there must be some kind of drawback I guess?

[bepeg4d]

Hi,
the Shadows pass has been removed, since it was necessary to multiply the result, while Black shadows works in both Normal and Multiply mode.
ciao Beppe

[Jahe]

but I can´t see what´s necessary to get that channel properly. I´m playing parameter roullette.


Sorry, but Octane is sometimes really a nightmare to work with. E.g. it robs me my sleep.

Having Geometry engine at "only updates" my scene lacks of one important object.
having it on "resend all" it looks fine in the liveviewer... but then ignores my "enabled render layer" and renders it without alpha.

To me that´s no reproducible behavior and, for the third time now, I´m tending to adapt everything to C4D Advanced Render shortly before the deadline.

[bepeg4d]

Please, always use the default settings for Geometry Engine, and Geometry Control:

Please, also share a scene that shows the issue with me via PM, thanks.
ciao Beppe

[Jahe]

Hi Beppe,

please find the file here on wetransfer:
https://we.tl/t-ulP0Jew9Ph

My goal is to have only the spheres, cube, flat cylinder on one layer with alpha channel.
Plus I want to have LBShadow and LRef of everything on separate layers.

Render it with liveviewer and it looks good.
Render it in Liveviewer (before doing that please turn Cam exposure from 30 back to 1. I don´t now why it´s that extreme) and the rendering looks like the room has no ceiling and the sunlight falls directly onto the floor.
That makes no sense to me.

Now... turn Geometry Control to "Manual Assignment" (because I expected there are refreshing issues) and it still looks fine in the liveviewer.
BUT when youn render it EVERYthing. Also the room that should be disabled by the Object tag with LayerID on "2" and Main -> Mesh number on "0".

I don´t get it.

[bepeg4d]

Hi,
please, keep it simple.
By default, all the objects are seen separately with ID 1, so, just add the Octane Object tag to the objects that you want to isolate, and change their ID to a different number, eg 2.
Then chose 2 in the Render Layer settings.
Also note that the Daylight object is un useful, and false the shadow result, just use the Environment node:

You can also group all the desired objects, and assign the object tag only to the father, to keep the things even more simple.

00113_05_Room_01_Forum_b2.c4d.zip

(181.73 KiB) Downloaded 144 times

ciao Beppe