Custom collison responses don't work

I’ve either discovered a rather serious bug in Unreal 4, or I’m grossly misunderstanding how collisions work in this engine.

Here’s my example scenario. I have two actors (one player and one AI) and I want them to be able to walk through each other. So, one of these is set to use the preset collision response “Pawn”, and the other is set to use the preset collision response “OverlapOnlyPawn”. Sure enough, with this setup, the two actors can walk through each other, no problem.

The interesting part comes when I switch “OverlapOnlyPawn” to “Custom…”, and don’t change any of the collision responses. If I’m understanding the system correctly, this should have exactly the same collision result as “OverlapOnlyPawn”, as all the channel settings are the same. When I try this, however, the two actors collide and push each other apart, as if the channel response were set to “Block” and not “Overlap”. This response occurs regardless of the collision settings.

Am I grossly misunderstanding how these should be used, or is there some underlying issue here?

Note: The collision responses work as expected if I create a new preset and use that. The problem only occurs when “Custom…” is used.

Hi Hoeloe,

Which version of the editor are you currently using? I just tested this in 4.4.3 and it is working correctly in-house.

I’m using 4.4.3. It’s definitely not working here - I tested with the scenario I suggested above - the Custom collision response setting is definitely not working.

Have you tried testing it in a new project with a non-custom character/pawn?

I’ll give that a try, but the only thing I can think I have done that might change the collision response is to add a second, trigger-only, collider to the pawn, which shouldn’t make the collisions responses simply not work like this.

EDIT: Yes, it does appear to work correctly in a new project. Is there anything I could have done to cause this error?

I’m not sure, I would say it’s most likely caused by a combination of settings that you are using. Try comparing the Details panel of your character & pawn to the character & pawn in the new template. Hopefully if you set them up exactly the same it will fix it.

Hi Hoeloe,

We haven’t heard back from you in a few days, so we are marking this post as Resolved for tracking purposes. If you’re still experiencing this issue, please feel free to post back here with additional information.