Written by me@grafxflow
UPDATE: Shadow catcher is now a built-in material and compositing feature in version Cinema 4D R18 onwards by default.
Part 1 - install the plugin and create a basic 3D scene (This page).
Part 2 - use Advanced Compositing to separate the object and shadow alphas... view it here.
What does the shadow catcher plugin allow?
Here is the scenario, we have a 3D character walking across the floor while casting a shadow. We want to composite this with an image in photoshop. Using shadow catcher we can render the character and shadow (with alpha) without the floor. Very useful.
Before starting... I had been searching for ages to try and find the C4D ShadowCatcher plugin. Luckily after pages and pages I finally managed to track it down back in 2008. So for this tutorial you can download it from this site (It's FREE). It has been tested in Cinema 4D R9 through to R17.
DOWNLOAD: ShadowCatcher for C4D repo
First quit C4D if it is running.
Then unzip the download and place it in the C4D plugins folder (Should be found in the same directory as the application)
MAC = Applications/MAXON/plugins/ShadowCatcher.cob
or
PC = C:/program files/MAXON/plugins/ShadowCatcher.cob
Now start C4D.
Lets create a scene and place a box hovering over a plane.

Then add a light with a target.

Choose the 'General' settings tab and change the following, 'Type' to 'Omni' and 'Shadow' to 'Shadow Maps (Soft)'.

Lets do a quick render...

Now apply a new material to the plain (this is what we want to act as our shadow catcher).


In the new material editor change the properties by unselecting everything except the alpha. NOTE: You may also want to check the transparency if you want to composite the shadow on a background image/video because by default it will be a pure black shadow.

In the alpha properties, click the down arrow next to texture and choose 'Shadow Catcher' (it should be near the bottom). You will also have to select 'Invert' option. If done correctly the material preview should be transparent.

Now lets go to the Render/render settings.

Now depending on which version of C4D the popup window will have a slightly different layout but the options are similar. So choose the 'Anti-Aliasing' option and change 'Anti-Aliasing' to 'Best'.

In the 'Save' tab, check the 'Alpha Channel' (The important bit!).

Choose one of the following:
1. If using in After Effects render as tiff frames and use the import tiff frames option in After Effects.
2. If using in Photoshop render the frame as a png format which will allow the transparency to appear straight away.

We're done!
There is a Part 2 - use Advanced Compositing to seperate the objects and shadows alphas... view it here.
Founder, Grafxflow
I am a Full-stack Developer who also started delving into the world of UX/UI Design a few years back. I blog and tweet to hopefully share a little bit of knowledge that can help others around the web. I build lighting-fast dynamic content engines with Laravel, Winter CMS and Tailwind CSS. Thanks for stopping by!
Cobus
15 Dec 2018
Thank you so much! I am really peeved with Maxon for including its its shadow catching material ONLY in its Studio version. This should have been a basic feature in versions ages ago!
Ahsen Tariq
15 Jan 2019
Is it possible with Octane or Redshift
Dawid
30 May 2019
Doesn't work with C4D R20 Prime. Not visible in Alpha -> Texture in material editor :(
me@grafxflow
30 May 2019
Sad to hear that Dawid... probably better to see if it can be achieved with compositing.
Currently it's only be tested with Cinema 4D R9 through to R17. :(
Robbie
18 Jul 2019
Thank you so much! You are my hero.
I don't know if this is already stated, but for me, the transparency of the shadow was always 100%. Even when I played around with the transparency in the material. (Step 9).
I found a way to control the shadow opacity by adding a Display Tag onto the floor and use the visibility and dropped it to 75%.
Adam
21 Feb 2020
Thanks so much for this. I am amazed that 3D software makes it so hard to capture just shadows. Seems so logical. Thanks for making this.
Is there a way to lighten the shadow though so it's not pure dark?
Thanks!
Adam
me@grafxflow
21 Feb 2020
Hi Adam,
Sadly I wasn't the person who originally developed this plugin, but I am guessing you could play around with the colour or opacity?
Here is a updated tutorial which might help tutorial link.
Also one thing to note - as from C4D R18 onwards shadow catcher is an actual built in feature.... finally! A nice part of this new options is that it also allows reflections as well.