I can add a post process to the camera in my pawn blueprint and it works as expected but I intend it for an effect for when my pawn collides with something (using the fringe effect for a fraction of a second to simulate a bumped camera) but I can’t find a way to activate or turn on the post process effect, it seems I have to either set it to on or off in my pawn’s blueprint
Hi rodstone,
This is definitely possible to do within your character blueprint although you’re about to be shown the largest blueprint node in the editor! (Don’t worry we’re reviewing ways to make this one a bit more manageable than it is currently!)
This is how I’ve set it up:
What I’ve done here is tied the post process change to my character jump. You can set that up however you like but this will give you a starting point.
The first set post process members node You’ll need to go through and Override (the top check boxes) any post process effects you want to enable by placing a check box (in this one Override Fringe Intensity and Saturation) > You’ll then need to scroll to the bottom/middle and find the ones you want to change.
I dragged a pin off and promoted to variable the fringe ones so that I could change them without having to go back into the blueprint again. By making these a variable that’s editable we can change this via the details panel in the blueprint.
At the very bottom for blendables drag off a pin and make a variable. Nothing needs to be done with this other than that.
This will enable our post process to trigger and change when we jump. I placed a delay between the other node of half a second. Then a post process members node that set’s everything back to what it was before. You can use variables in the settings to adjust the original values or you can just uncheck the overrides to use the defaults.
This should be enough to get your started. If you have any questions feel free to ask! 
Tim
Thanks very much! I actually stumbled across those massive nodes but gave up when I saw the size of them! I should have persevered! That’s perfect thanks
It’s a bit daunting but it’s the only way for the moment to get the job done within your character blueprint. If you have any questions I’ll gladly help!
Wow dude, I need ctrl+f to find nodes 
ty for posting this Tim. Found it helpful!
I have an issue (using 4.11). Any node regarding post process settings appears blank when I try to expand the node (via Split Struct Pin). Even the Break PostProcessSettings and Make PostProcessSettings nodes become blank, so there is no way to actually view or edit this stuff…
Thanks, Tim
You can try with Set PostProcess Blend Weight.
Pro: So simple!!
Con: Target is a camera actor, so It only works with in-camera embedded postproduction.
Luckily it worked fine for me.