Render Object with Transparent Shadow

[BigAl3D]

I'm in the middle of my project now, but am pounding my head that I couldn't remember how I did this in the past. I have a car on an object which will eventually be placed over a still of that base object in Premiere. In the past, I figured out a way to export that car AND the shadow as one piece, RGBA sort of thing. The closest I was able to get before having to abandon ship and start rendering a separate pass for the shadows, is the vehicle with a shadow, but you can still see the form of the base object it is sitting on.

I apologize I can't post details or files yet, but wanted to put it out there. I put a Shadow Catcher Material on the base object and of course the setting inside there is where I'm sure I'm missing something, but I have tried multiple combinations of Environment/Sky Object/Compositing, Backplate/...... then I enable Multi-Pass and add Mask, Alpha, Shadows and anything else I can think of.

One question on Multi-Pass. If I enable a bunch of passes, does that add to render time, or is Corona rendering that info anyway and I'm just separate them?

Thanks for any tips.

--Alex

[maru]

Sorry for the lack of response here. To render an object with its shadow so that you can compose it in post, you should use the Shadowcatcher material set to "for compositing". Note that ideally directly visible enviro should be set to black, I left it enabled in my example just to show what is going on.

As to multi-passes and performance: they do affect render time, but the difference should be negligible.

[BigAl3D]

Hey thank Maru for the refresher course. I will give this a try and post back.