Depth of Field masking. I think there is a camera that does it here. You make a render and then use a depth of field render which makes object closest to the camera whitest and darker as they go farther from the camera.
I am not sure if the DOF camera works in DS4.5, does it? There was one for DS3 called Atmospheric Camera but I am not sure if it works for DS4.5.
Anyone know if it stills works for 4.5?
You can also do a workaround as well.
Setup your render and all the elements you want to be in the render. Also setup a primitive plane that runs parallel to the image plane.
Color this plane a color that does not appear otherwise in your render. Green is commonly used but so can purple if that is not in your render otherwise. Also, if there is not a lot of pure white or black in your render, this is also an alternative but make sure there is ZERO specularity or reflection on this plane. None. It should be as matte as matte can be.
Render your scene once WITHOUT the plane in place.
Find the elements in your render that are closest to you and place that colored plane so that it is in between your foreground objects and the next “layer” of objects. It does not matter if you have reflective objects or that color and it will become clear why in a few steps.
Repeat the process of slowly pushing the pane father back and rendering. Try not to have the pane intersect an item (there is a way to straighten this out too but I digress).
You probably don’t want to do too many. The most I have ever used is five planes.
Take all of your renders and place them into photoshop in the order so that the layer where the plane was closest in the top layer.
Use the Magic Wand tool on the color in your color plane to make a selection, then make that selection an alpha mask. Do so with each level. You now have masks that you can use on your first render that had no “plane” in it.
Use the alpha masks to help you make selection masks for gaussian blur or any other filter you may like.
You can also make multiple copies of the first “Planeless” render, then eliminate the areas covered by the alpha masks on each layer so that you may interject all new layers or images into a layer.
Hopefully this made enough sense to follow.
Sorry about any confusion.