Im designing an item viewer that you can use to rotate a mesh in world space while the rest of the background is blurred. I’ve completed the rotation part but cant manage to get the blur working. Adding a postprocess simply to the character doesnt seem to work well, or maybe Im doing something wrong. Is there a way to render on different ‘layers’? Thank you.
I’m no expert, but if I were to do this I’d create a semi transparent blur in photoshop and have the middle completely transparent, and just have that display while viewing the item, I’m sure there’s a way you could loop the visibility to make it look smoother as well.
What you are looking for is called “Depth of Field”. Please have a look here. If a static DoF is not enough you can implement a dynamic one, which you can find here.
I hope it’s going to help you. hfgl 
EDIT:
As you can see in the image below, you have a ‘Focal Region’ which is the focused region.
In your example you should move this region to the very beginning. You can do it by setting the ‘Focal Distance’ property to a quite low value. As a result everything direct in front of you will be sharp and everything else is blurred.
Thank you for your reply.
I’m aware of the focal region property and have already tried it at several values. The result is not sharp as I want it to be and there seems to be considerable blur near the view.
Did you already tried:
Focal Distance: 0.0
Focal Region: 100 (or higher?)
Near Blur Size: 0.0
Far Blur Size: 2.5 (or lower/higher?)
This worked out quite well for me.