Hi!
I’m using Unreal 5.3.2 and I have modelled this mesh with Maya, cloning it and adding it the cloned shape as an UCX object.
The UCX
I’ve imported to Unreal without selecting Generate missing collisions.
When I edit the mesh and select show complex collision I see this:
But, it I select show simple collision, I see thins:
Which collision will the engine use it?
Thank you.
Hey @ViaCognita!
The engine should use whichever collision complexity you have set for that static mesh.
I hope the above is the answer you were looking for!
Since you’ve cloned it, I don’t think it matters much - the complexity of the collision was not reduced in any way, was it? It would only matter if the object needed to support physics simulation for which Simple Collision is required.
without selecting Generate missing collisions […] I select show simple collision
This does not look right, though, indeed. It looks like the autogenerated Convex Decomposition… Afair, the Generate Missing Collision flag is ignored when you provide custom Uxx collision, which you seem to be doing correctly. Admittedly, I’ve yet to use the feature in UE5 specifically.
What are the chances you accidentally generated Convex Decomposition in the editor, overriding UCX?
Regarding which collision will be used - the one selected from the dropdown but the UCX does not seem to be in place. Chances are it’s not a valid shape and does not get exported / converted at all:
Not sure what you need the collision for, but the most efficient approach would be 3 boxes that are very close but not touching. Something like this can be even done in the editor manually but is clunky to use… 
Hi all,
I think the ‘concave’ areas between the cubes might be breaking the UCX import?
As an alternative, there are some collision tools in the ‘Attribs’ section of the new modeling tools. (Imagining placing+sizing a few boxes with ‘Simple Collision Editor’)
@Everynone Thank you, but which collision will the engine use it? Simple or Complex? I’m sure there must be a mechanism to select one of them.
Thanks again.
As mentioned above, you select it yourself with a dropdown after double cliking the asset. In the details panel, there should be 3-4 options to choose from.
And when it comes to tracing, nodes have a boolean toggle letting you enforece tracing against every poly.
Where?
In the details panel after double clicking the asset.
Hey there @ViaCognita! Just to add some documentation to the mix, here’s a bit more information on the differences between the collision complexities as well:
