Physics objects falling trough meshes using complex collision as simple

Development World Creation
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I’m using Hammer editor to make maps for a game and set all the meshes to use complex collision as simple, since manually re-making the collision for the whole level would take ages. Unfortunately, this causes a lot of objects to straight up phase trough the ground, especially when they move fast or have another object fall on top of it.

I tried enabling sub-stepping, but even at high settings things still consistently phase trough the walls.

As far as I can tell it’s caused by walls being infinitely flat and manually adding box or hull collisions solves it. Unfortunately doing it manually isn’t realistic and the automatic generation is too inaccurate.

I couldn’t find anyone else having this issue, so I’ll just mention I’m using Unreal Engine 5.3 just in case it’s something version-specific. I can also provide the specific meshes I used in the video, but the problem doesn’t seem to be mesh-specific.

EDIT: I tried enabling Continuous Collision Detection (CCD) on my mesh. Previously I didn’t try it because I thought it was a project setting, not a mesh one, but after enabling it on all offending actors that seemed to resolve the issue to a satisfactory degree

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I seem to recall that physics only works with simplex collision. Maybe someone will correct me on that…

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You are never wrong maestro Clockwork. How can you doubt yourself now? :stuck_out_tongue:

You can set all of the ‘static’ level geometry / static meshes to Complex for now (also look into merging parts of the level maybe). But this may hit performance down the road. For now, just set-up a subset of the meshes that absolutely need physics to simulate, or cheat with kinematic (interp) movement. After a while you’ll get used to having multiple copies of the same meshes with different types of collision. :wink:

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Oh can be, definitely :rofl:

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Complex as simple is the stup1dest thing one can do for videogames.

All the bugs - 0 benefits - 100% lazy.

Just generate collisions.

And for a floor, you usually want a thickness of at least 10uu - preferibly more like 100uu (1m) so you dont get issues later on, but minimum around 10uu.