Product Imagery / Transparent Backgrounds with Shadows

[shoebu23]

Hello Forum!  Looking for some advice on how to streamline a specific type of consumer product shots (3dsmax).

Question:  How best to get higher-volume products shots on transparent background with shadows on their own layer (typically in a PSD or TIF file).  There are a couple of small things that come up that I would love to streamline if anyone has suggestions...

Here is my typical workflow...

MAX:
1.  Place product on shadow-catcher and set to compositing mode.
2.  I typically have a set of lights used just for the shadow I'm looking to achieve
3.  Render just the product (typically use render-selected option).  Save as PNG w/ Alpha
4.  Change the product property to setting to 'not visible to camera'
5.  Render shadow catcher and save as PNG w/ Alpha

PHOTOSHOP.
6.  Drop in shadow layer.
7.  Apply a slight blur to the layer to get ride of noise **this is because the de-noiser does not clean up the alpha channel**
8.  Drop in product
9.  Apply a de-fringe to layer **the products always seem to come in with a small black fringe from Corona**
10. Name things and save to TIF or PSD.

Sometimes I simply use the MaskID pass to separate out the product vs. shadow so I don't have to render twice, but the problem I face is I apply a blur to the shadow layer to get rid of noise which then muddies against the product since it doesn't go underneath it (hence, why I render twice and set the product to not be visible to camera so I can get the shadow underneath it).

Seems like a couple unnecessary steps for higher-volume product shots so any thoughts, advice would be appreciated!  Cheers

[romullus]

9.  Apply a de-fringe to layer **the products always seem to come in with a small black fringe from Corona**

So far i found single solution that gives no fringe. You need to render an object on black background with alpha render elemet active, save beauty layer as PNG, or TIFF with alpha enabled and save alpha layer with alpha disabled (sounds like mumbo jumbo, i know) Then load both images in photoshop, or other program and mask beauty with alpha layer. This gives perfect cutout. All other methods that i tried, gives either black, or white fringe.

[shoebu23]

Thanks for the tip on this- certainly helped!  Here is what I ended up moving towards... admittedly a bit strange, but is working nicely...

1.  Set Shadowcatcher to 'Always Transparent' ... NOT compositing
2.  Use rayswitcher to have 'Direct Override' set to WHITE on Shadowcatcher
3.  Beauty and Alpha pass saved with NO alpha

Two layers in Photoshop
1. Mask Beauty Render with Alpha Render (seems to get no fringe and allows for transparency)
2. Have Beauty Render with no mask underneath the masked layer and set to multiply**

** This is why I am using Rayswitcher so that the beautiful shadows are captured on white so it can simply be set to Multiply blending so it can be placed on any surface at the client.  Since it is denoised and no relying on any alpha channels for the shadow, which doesn't get denoised-- I can get away with only a couple render passes.  When set to compositing, it takes longer and the results are not as good.

Anyways, thought I would share