How can I make a mesh navigable


I have downloaded a house mesh and want to make my agents move inside through the door. The house consists of several submeshes that I have added into one blueprint.

The problem is that by default the whole mesh is not navigable. I can set the collision preset to “NoCollision” but the agents will just move through the walls then.

This is the navmesh with collision set to “Block All” on all submeshes of the house:

I assume I would have to alter the collision meshes of the sub meshes somehow, but I am not sure how and if this would be the right way? Take this example of the entry area: The complex collision mesh looks fine, but the simple mesh covers the door area, I assume that is the problem?

How can I fix the simple mesh to allow navigation? I am not a 3d modeler and I would like to avoid working on the mesh in an external software if possible. Or is there another way to make the house navigable that I am not aware of?

Thanks in advance


The complex collision mesh looks fine, but the simple mesh covers the door area, I assume that is the problem?

By default it will use the simple collision and since that is blocking the door area you won’t be able to move through that. So you need to adjust the simple collision. For that you have two options

(-) Directly do it in engine (you can either autogenerate it or if that doesn’t work add several box collisions and place them so that you still get somewhat good collision on the wall but nothing blocking the door)

(-) Create a collision mesh inside a 3d modelling program and import that (has the advantage that you can shape it more precise than using boxes).

And ofc for really low poly meshes you could use complex collision as simple. I guess for the mesh you’re showing there I would just use complex collision as simple. So here you would set Use Complex Collision As Simple Simple versus Complex Collision | Unreal Engine Documentation

Here’s the doc about adding collision in engine Setting Up Collisions With Static Meshes | Unreal Engine Documentation so you can add several box collisions

And if you want to know how to import a custom collision mesh from a 3d modelling program, that’s described here under Collision FBX Static Mesh Pipeline | Unreal Engine Documentation

1 Like

Awesome, thank you!