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Complex Collision for moving objects

Development Discussion Blueprint Visual Scripting
#1

Hi,

I couldn’t find an answer to solve my particular problem. Actually, it’s almost the same as Complex collision for moving objects - UE4 AnswerHub

I’m using the rolling ball template. I want to make an obstacle course. I created a tunnel (static mesh created with a hollow cylinder shape).
This tunnel should rotate above a cliff, so the player has to have the right timing to get over that cliff through the tunnel.

The problem is the collision. I created a blueprint, added the tunnel, added timeline + rotation. The rotation only works if the mesh is movable. The collision (complex as simple) only works if the mesh is static.

So my questions are:

  • Is there ANY way (be it c++) to enable complex collision on movable meshes?
  • If not, how do I create a “tunnel collision mesh” in UE4?

Thanks,
Ben

#2

I think your best choice is to create the tunnel in 3d yourself, and create a mesh that will be the collision in UE. After that comes the ticky part. Name your tunnel e.g. Tunnel01 (what a genius name:eek:) and name your collision mesh to UCX_Tunnel01 and export. Import it and there you go:)
I hope it helped.

#3

Or you can enable the Use Complex Collision as Simple in your Static Mesh to have per-poly collision. I usually use that a lot. :slight_smile:

#4

Thanks Sim220, I could import it. It’s working now, but it’s a real performance break :slight_smile: I guess I have to come up with a more simple collision mesh for the tunnel.

@ryanjon2040: that only works if you do not want to move the mesh around.

Anyone knows why creating a static mesh is not a performance killer when “complex as simple” is activated whereas an UCX collision mesh is a real break when the object is set to movable?

#5

Hi guys, i belive i found the answear or at least neat solution (depending on how advanced is your mesh).
Import it without collisions, and then use auto convex
image
then pump this numbers up
image
depending on what you need.
Hit apply,
and you’ve got yourself simple collision that might be more complex than complex.

Works perfectly for my d12 dices.

Last word: kinda obvious this is performance killer, dont use it when you dont need. Try not to make too many of them.
I know you wont need this, since this is from 2014, but popped for me as first, so it might help somebody.

#6

The problem with the tool is that while it may work fine for simple shapes (like dice), it will make a mess out a more complex one. Try doing something concave / irregular and watch it squirm, producing chaos… It’s sometimes better to add shapes manually, tbh.

What you’re suggesting is an OK quick fix or for a somewhat regular shape. But if you want a neat and efficient simple collision, you will need UCX as mentioned above.

Not sure why Ben_Cykyria had performance issues with it. You absolutely must simplify the shape before exporting - perhaps the attempt was per poly.

Old tut that is still very valid today: