render drop shadow without a floor

[edecker]

Hi guys,

For the life of me I cannot figure out how to render an item like a ball with a drop shadow for composition later. I need the shadow on the floor but no floor so the final render is the ball with a drop shadow.

Thanks!

Eric

[Tomas Egger]

Ola Eric,

The secret is in the group info window:

Look my projects, if you want, change the color floor to be dark like your shadow. :)

Project attached:

Metal Ball - Shadow.zip

Thanks

Tom

Hi guys,

For the life of me I cannot figure out how to render an item like a ball with a drop shadow for composition later. I need the shadow on the floor but no floor so the final render is the ball with a drop shadow.

Thanks!

Eric

[edecker]

Hey Tom,

Thanks for posting that project file. I now know why it was not working for me. I am using only GI lighting and one radial for specular (set to highlight only) and it gives nice soft shadows on the object and to a floor but using GI lighting alone will not allow the generation of a shadow mask. Any thoughts on getting the GI shadows to allow the mask generation?

Project attached:

test_shadow.zip

[Arketype]

You can use the Layers Shader to do this.

Render with a white floor and all objects Final Render and set to "multiply",

And put your foreground objects only (do not include the floor) in another selection set

and render this with the "final render option.

Open the layered Photoshop file that is rendered and drop your background image behind these other two layers.

Works really well.

Dave

[Tomas Egger]

Ola Dave,

Thanks for the tip

Tom :)

[edecker]

Dave,

Excellent tip. Unfortunately I am rendering a sequence of images and my delivery is a set of png with transparency except for the item and drop shadow so this approach will not do it this time. The floor is still retained on the Final Render layer so it is not transparent. It has given me some other ideas on how to achieve this by modifying what you suggested.

Thanks,

Eric

[edecker]

Any other ideas are accepted. I cannot figure out how to do this and get a clean soft shadow sans the floor it is projected on to.

Thanks,

Eric

[apu]

What i usually do is rendir the whole sequence And them render only the objects in the foreground in another sequence. Then in aftereffects place the whole sequence below And set to multiply. Duplicate this layer And set it to normal. And place on top the render with the foreground objects. Then tell the duplicated layer to use the alpha channel of the layer of the foreground objects.

Hope this helps

[edecker]

Totally helped! I did change mode of the top layer to Silhouette Luma and bingo!

Thanks so much.

Eric

[Tomas Egger]

Ola Apu,

Great Tip :)

Thanks

Tom