Use Collision Complex as Simple doesn't work with Physics

When I try to turn on use collision complex as simple the collision works fine, but when I simulate physics and add mass in kg the object is static and will not move. Yes I have made sure to make the object movable, but it still does not work. If anybody has any possible solutions to this problem I would be glad to hear them.

You can’t use triangle mesh collision on physics objects.

same problem here, I don’t know how to add “use comlpex collision as simple” and get it to work by any means, can anyone help us in here ?

Guys, okay first things first, setting Collision complexity isn’t going to magically create a collision hull for you. Maybe you already have one because it was automatically created, or maybe someone else created it for you, but the first thing you have to do is make sure you have a collision hull. Open your mesh in the editor and on the toolbar there is a big collision button, with a little downwards pointing arrow for the drop down. If you check the complex collision checkbox, do you actually see anything? If you uncheck that and check the simple one, do you see anything?

If you do not see anything, you need to actually create a collision hull. For simple objects, just create your own collision in the static mesh editor. There is a Collision menu in the menu bar above the tool bar. There are lots of options - automatic convex hulls, boxes, capsules etc etc. Use the simplest collision you can for smaller objects. You can manipulate the hull mesh using the standard translate/rotate/scale tools. And you can add more than one hull mesh if you have bits sticking out of static mesh, your asset itself. So say your asset was a solid cross shape, like a + sign. You could create two box collisions, one for the north/south or vertical part and another box for the east/west or horizontal part.

So hopefully if you have made it this far, you have a collision hull, you just need to set up a few settings.

So Collision complexity would only be “complex” for big objects like terrain, buildings etc that do not move. You want “simple” for smaller objects like weapons and projectiles that are going to be moving around in the world. And I am guessing that you would use “simple and complex” for moving objects that also have complex shapes, like aircraft, spacecraft, cars and tanks.

Now, you need to enable Simulate physics. This should only be possible when you have collision in place.

Now, you need to set your Collision presets. Use BlockAll if you do not know what you are doing, to see if it works. Then you can read this and put something more sensible in.

Hope that helps.


Sry to reopen this question, but in my case I want to have a moveable complex collision non convex mesh to simulate physics. It’s arim of a tire, and I want to be able to push a bar through the center during runtime which should be able to collide with the inside of the rim-hole.

Just to close my question:

Never heard of Custom Colliders before, but they solved exactly my problem, even tho it’s a bit messy now :D.
Thanks a lot.