Performant Cylinder collisions for pickups? Or way to Z scale Sphere Collisions?


  1. I need a Rotating and round collision for pickup items > Interaction area for Overlap Events that turns things on BEFORE player gets close enough to touch the item in the center.

  2. But I also need to reduce the Z height = make shorter, yet keep it wide/fat (X,Y).

  3. So I cant use a Capsule or Sphere collision (because I need wide a radius, but the Z height is too big, thus a Player on the floor below the Pickup could touch it, since I cant change only Z height (scale) on Primitive Sphere collision? I also tried to use a Construct script to Z scale the Sphere collision component, but it changes scale of X,Y also.)

  4. So I tried a Cylinder MESH, but is 512 triangles (times the # of pickups in a map) - too many draw/collision calls vs if I used a Sphere collision?

  • I.e. NO, not too many tris/calls, it is Performant (the difference doesnt matter to 2020 computers (I want it to work on people’s older laptops)). Or YES too many calls, not Performant when scaled = many pickups?
  1. And I cant use a Box collision because the Rotation component makes it spin, and I use Overlap events. Thus the spinning Box causes unequal overlap triggers.
  2. So what should I use for the interaction area collisions of my perfomant Pickups? Thank you.

Could you use a shape (BSP volume) and maybe make it octagonal?
BSP volume overlaps are frequently used for triggers and other volumes.

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Ty but what is a BSP volume in context of a BP actor? I dont see “volume” as a search option to add as a component.

I maybe found a partial solution by using #5, a Box collision (closer to the Z shape I need to adjust), and make it NOT auto Rotate, by:

  • Selecting the Box > Settings Panel > click on “Rotation” to access the dropbox > set to World (rotation type).

  • This seems to stop the RotationMovement (addon) from rotating the Box collision. But the rest of the components of my pickup do rotate (wanted).

UE4 how to turn off forced Rotate of a Box collision

Cons are: still a box shape, not as round as Id prefer.

They are generally referred to as "Volume"s. It may be that you need to separately place a volume, and then link that as an actor reference to the blueprint object you’re interested in.