I’m having what seems to be a simple problem that I can’t quite figure out. I’ve modeled a very simple box in Blender that has a hole on the top of the model:
What am I doing wrong here? My expectation is that anything small enough to fall into that hole would fall into it based on the collision meshes that I am exporting.
Hey, n0t0rigina1, I think you are encountering an issue here because your meshes are being converted into cube-simple collision volumes inside the engine. This is just a guess, as I am not super familiar with exporting custom collisions from Blender. However, it is very easy to check if this is the case by turning on the player collision view in the editor or by going into the mesh asset and checking the simple collision view. Additionally, if you reference this tutorial, you will notice that when creating the custom collisions in Blender, any concave shapes, such as the window, are created from multiple simple convex meshes rather than one concave mesh. (They make the sides of the square hole out of cubes rather than out of one mesh with a hole in it) I would recommend doing something similar. Unreal has many different options for collision, so if you have any more questions or want to know more, just let me know.
Well, that’s not necessarily true. Usually, if there is no collision, you wouldn’t see anything while in the player collision view mode. So there is something there - even if I have never seen that coloration before. Is the “simple collision” turned on under the “Show” dropdown, and if you go to the collision primitives section in the details, is there anything there?
Well, I figured out a working solution (not quite sure if this is the correct way). I had to triangulate the face surrounding my hole in Blender, and then make a collision mesh out of each of the subsequent faces. So I was left with something like this:
Simple (aka UCX) collisions can not be concave. You have to either use complex collisions for holes in objects, or build up the collision with an apparent hole out of multiple convex shapes (more or less like you did in your workaround).
