UE 4.11 Preview 5 collision bugs

Development World Creation
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1

When I started our current project in UE 4.11 preview 5, enemies fell through the floor right after spawning.
I managed to prevent this by manually doing “Set Collision Enabled” to “physics and overlap” during “Begin Play”. That was NOT necessary in 4.10. The editor setting of the respective collision capsule is “physics only”.

Also a capsule trace executed when a weapon is fired suddenly started hitting the player to which the weapon is attached. I finally tracked it down to some problem regarding collision object types. The player’s capsule is set to a certain custom object type, and the trace is looking for a different object type, but does return the player’s capsule as a first hit for some reason.
I managed to “fix” this by setting the player’s capsule to a different object type, though that obviously breaks other parts of the game.
When I have the trace look exactly for the object type of the player’s capsule (with its proper object type), it does NOT hit the player’s capsule, though. It only does so when looking for something else entirely.

2

Hi abeccu,

  • Does this occur in a clean, blank project with no additional content or is this limited to one project?
  • What steps can I take to reproduce this on my end?
  • Are you using BSPs or static mesh actors?
3

Hi ,

I am using static mesh actors.

I’m going to try to reproduce this in a blank project. If I find any way to reproduce it there, I’ll let you know.

EDIT:

I could not get it to fail reliably in a blank project.

4

Does it seem to occur with specific actors? What are the collision settings you are using?

5

Hi abeccu,

We have not heard from you in several days. I am marking this as answered for tracking purposes. If you are still experiencing this error, please comment with the requested information.

6

Hi ,

I managed to isolate the problem with the enemies falling through the floor.

It happens if the respective collision capsule (root component) is set to “Physics only”. If switched to “Query and Physics”, the enemies no longer fall through the floor.

This worked just fine with 4.10. I’ll try to reproduce it in an empty project.

7

I managed to reproduce it:

  1. Create a fresh project, “top down” template.
  2. Open the TopDownCharacter blueprint
  3. select the capsule component, switch collision preset from “Pawn” to “Custom”
  4. Set “Collision Enabled” from “Query and Physics” to “Physics only”
  5. Press Play

The player character will fall through the floor.

8

I also found another problem that looks like a bug.

“Get Hit Result Under Cursor by Channel” with trace channel set to “Visibility” returns collision capsules which have “Trace Response Visibility” set to “Ignore”. (It always returns the first, i.e. largest, capsule hit.)

I assume this is not intended?

9

Sadly I wasn’t able to reproduce that problem in a clean project. I managed to fix it in mine by switching back and forth the collision type and trace responses several times.

10

It’s probably the same problem I have here: https://answers.unrealengine.com/questions/378384/trace-channel-buggy-in-411.html

11

Hi abeccu,

The reason for the character falling through the floor is in part because the capsule, while coded to simulate a physics object, is not technically a physics object and will react poorly to physics only information. Specifically, if you check “Simulate Physics” to true and then set collision enabled to physics only, it will no longer fall through the floor but you will not be able to move. The setup that works best in this case is both physics and query, which should prevent your character from falling through the floor. In regards to the trace channel error you are seeing, I have not been able to reproduce this on my end. What steps can I take to do so?