3DS Max Collision Not Converting

i’ve been watching some videos online and even read from UE itself to try and understand how to create the collision for an object in 3DS Max and then import to UE. I created the mesh I want, and then cloned all components that I wanted to act as the collision boxes (The mesh had shallow protrusions that I did not want to generate collision), and then I named each of these cloned objects “UCX_[Filename]” and then exported. But, when I import, the collision boxes do not exist. Can anyone help me out here?

You have to name your collision meshes as “UCX_[Meshname]”, NOT “UCX_[Filename]”. [Meshname] is the name of the mesh you want to apply collision to.

I tried this but it did not work. The meshes I want to apply collision to are boxes that have been shaped as rectangular prisms. I named all of these “UCX_Box” and it did not create any collision prisms.

You will also have to make absolutely sure your collision mesh is convex. From what you’re saying, it should be, but concave collision meshes are not imported at all.
When using multiple collision meshes for a single object, you might also want to name them UCX_[MeshName]_001, _002, etc. (though all of them having the same name without a _### suffix should work).

-make sure that you use basic shapes for your collison
-disable “auto generate collision” in your import settings :slight_smile:

I have “auto generate collision” disabled in UE; and the shape I’m using is a box from the very first “create” panel at the top of the drop-down menu in 3DS Max, so it should be as basic as possible.

Some convex objects are adjacent in such a way that if they were to be considered one shape they would be concave. I looked up that objects in this type of arrangement should be separated by a small space for “best results,” so I separated the shapes slightly but there is still no collision mesh.

So you still dont have a collision? -> what happens when you just add a box to your scene + another box as the collision + export it + import it? After that we know if it’s an import error or something else

I created a box in 3DS_Max and set the dimensions to 30, 30, 30. I cloned the box and changed the color to black, and renamed it “UCX_Box,” then saved and exported the file as “CollisionTestDummy” in both cases. I imported CollisionTestDummy into UE. It has zero collision prisms.

So you export both parts separately? -> keep them together and export it, also make sure that everything is in the same scene/layer of 3ds max + could you share your fbx file so that I can check it?

I exported them the same, but I meant that the name in the Save folder and the Export folder are the same.

I can’t figure out how to upload an FBX on the forums here. It says “Choose file,” but there is no upload button that corresponds to the file chosen. If I press “Upload” associated with a different panel it gives the following error message “CollisionTestDummy.FBX - Invalid File.”

So I’ll provide some images to explain what is happening…



You have to choose the exact same name for your collision! → so in your case UCX_Box001 + also disable “one convex hull per…”
Upload the iles on gdrive or dropbox → here in the forum you can just upload .txt files

Oh I get it! It has to have the same name as the object it is acting as a collision box for, and not the name of the shape used! Thanks, fighter!!