Hello Colt,.. is this only for a screen render... or, to a png/tga file with a alpha channel?
Hi Paul, I want the final output to be a png file with alpha channel so I can eventually make a composite image with multiple renders that may overlap. If all goes well then I should be able to change the background color of the composite without re-rendering.
In playing around with it to show the issue I got the result I was looking for. Now that I know it is possible I just need to figure out what is wrong with my other assembly or why my macro is failing.
Raw image complete transparency with shadow
This image was not a re-render but a background color edit.
I don't really get how you would have a shadow without a surface to project it onto. You can definitely remove the reflection that appears on the floor, but I don't think you can have shadows if there is no floor.
I guess the problem was that I was using a camera. If the render is from camera perspective the floor is shown as opaque. Using the screen render the transparency is correct. This must be a bug then.
Edit. This was caused by me doing a scene change which reset the visibility of the floor appearance.
Looks great but the floor is not transparent. No changes except use a camera for render.
with background change
The final solution was to delete the floor appearance and keep the shadows on. Even though there will not be a floor visible in the final render the shadows still seem to be cast on it. Therefore, before you delete it, you need to make sure the floor is big enough to catch the shadows or no shadow will appear where the floor once was.
Then you can do some cool stuff like this.
A resultant image with overlapping semi-transparent shadows.
Thanks for all the help everyone.