Can't simulate physics because of ComplexAsSimple collision

[anonymous_user_206353df]

I don’t know if it’s the right category and tags but never mind. can someone please explain me, why can’t I simulate physics on actors that uses complex collision as simple? I have a ram skull which I downloaded from Quixel bridge and I tried to edit it in blueprint and add some functions to it but when I try to simulate physics on it (via the blueprint) it’s says error. it cannot simulate physics on complexAsSimple collision. And I need the complex collision I don’t want to switch to simple box collision I need to keep the complex. anyway to solve this problem?

[Rev0verDrive]

You need to either export the mesh and add custom collision in Blender, 3DSM or other 3D modeling software, or add primitives to it in the SM editor. A simple convex collision from the sm editor will work.

FBX Static Mesh Pipeline

There’s loads of tutorials on this.

[Everynone]

why can’t I simulate physics on actors that uses complex collision

That’s how the engine is set up. It would be too taxing to simulate on millions of triangles in real time. You can simulate against complex (a ball rolling down very complex terrain) but the terrain cannot simulate itself.

@anonymous_user_206353df

I don’t want to switch to simple box collision I need to keep the complex. anyway to solve this problem?

It does not need to be a box:

The auto-convex can generate more advanced shapes, too:

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But the best advice is in the previous post. If you need custom and accurate collision that is also performant, look no further than this:

UE4 - Tutorial - Custom Collisions! (Request!)

[CorruptClaw08]

I have noticed that I am getting the same problem with ComplexAsSimple collision, but I have noticed on my object that there is a button for me to change its collision complexity. Would you recommend that I click on that and then press on “Project Default”, “Simple and Complex” or “Use Simple collison as Complex”?

(Just showing how it looks like on my end)

[Everynone]

I am getting the same problem

What problem? Complex Collision is static and cannot be simulated.

• if we have a bunch of immovable craggy rocks players needs to navigate on with a high degree of fidelity, and one cannot be arsed to laboriously craft neat collisions, use Complex as Simple
• if you need something to move, rotate, simulate, interact with other entities or be overall performant, stick to Simple Collision. There’s a bunch of different ways to get the correct collision shape:

Collisions

Pick one: use a ramp as the collision shape, players move smoothly on ramps - easy and efficient if the stars do not need to move, use complex collision - it’s generally fine for stairs but can mess with navigation and is not as performant (borderline irrelevant unless your levels are made purely of high poly staircases) use Convex Decomposition in the mesh asset panel - can work OK at times carve collision shape using brushes, convert, use as collider - a.k.a. poor man’s UCX manually & labori…

[CorruptClaw08]

Hmmm okay, good to know. Thank you

[usa423]

Collision hell.