post-production - diamond

[fario]

Hello, I need your help and thank you in advance for your teaching.

I'm not a big user of Photoshop and I think my question is a beginner level.

This subject concerns the post-production, after the calculation of images with Keyshot.

Often diamond prefer a HDRI environment different from that used for other materials of the same scene.


Domain: watchmaking.
Problem: photorealistic diamonds in several passes.
Request: get an excellent rendering of white diamonds.

scenario:

Keyshot
calculating an image of a metal support without diamond. HDR (1) ideal for this support. -. Png
calculating an image of white diamonds only. HDR (2), ideal for those diamonds. -. Png with alpha channel.

Photoshop
2 images import and assemble.

-

my problem:
How to hide the cones of diamonds, which are normally below the surface of the metal support?

thank you very much for your help.

my video:

http://screencast.com/t/Cb1A1lYoVc

the files for test.

Antoine

[PhilippeV8]

Try this:

Keyshot
calculating an image of white diamonds with metal support, but give the metal support a "flat" material that has the exact same color as the background.  (e.g. white or black).

Carefull now, cuz this "invisible" metal support will block the view of those cones, but at the same time will show up on the alpha channel !  Therefore make yet another render pass with the same settings as above, but with the diamonds also a "flat" material with the oposite color of the background/metal support.  This last render will become your alpha channel.

[fario]

merci! Philippe,

I keep your valuable explanations in my case

I see that Version 4 offers Keyshot rendering by layer, it should also respond to my request.

Again thank you for your feedback.

Antoine