Defocus node with external renderers
Blender now has a node based rendering system and one of the nodes is Defocus.
Indigo test
I made a very quick test with Indigo. Here is the image without defocus:
And after defocus node:
How was this made?
Defocus is image based so all you need is an image input and Z-buffer input. Image input is easy. Just export to renderer, save image and get it back to blender with image node.
We can have Z-buffer for that image by letting Blender to render that for us. Just like normal use of Defocus node.
Here is the setup:
Why?
Why would you want to use defocus node if renderer has that ability allready? One reason could be speed. Because Defocus is image based, the scene complexity does not affect to the processing time.
topConclusion
In order to work the output of the external renderer must of course match to the Blender's internal renderer. There seems to be some artifacts in the defocused images (jagged edges). It is possible that could be fixed by using larger images.