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Import level mesh/collision detection

Development Discussion Content Creation
#1

Hey there,

I just started working with UE4, covered some very basics.
Now I want to port my stuff from an earlier project to UE4, in this case, a finished worldmesh. It’s a .3DS imported in Blender and exported as .fbx.
Only problem here: There’s no collision. Checking auto create collision just creates a collision hull around the mesh and any other option for collision generation is not accurate.

I just want to have accurate collisions to every plane, wall etc. so that you can actually walk on the ground without floating a bit above and walk through passages.
I’m actually not a 3D artist, so the worldmesh isn’t made by myself, but I got the basics working with Blender.

Thanks in advance.

#2

You will either have to set up collision in your FBX file by editing it in Blender or equivalent: https://docs.unrealengine.com/latest/INT/Engine/Content/FBX/StaticMeshes/index.html#collision

Or within the scene add blocking volumes where you want collision to be: https://docs.unrealengine.com/latest/INT/Engine/Actors/Volumes/index.html#creatingvolumes

#3

So there’s no way to, like, set every face of the mesh to be solid/have collision?
All I read about is creating boxes or something similar to put around the mesh to serve as collision box.
To be more precise, it’s a pretty old world mesh, containing a fort in the middle and a little village around it, additionally surrounded by some sort of palisade, which is just like a 2D plane or something.

Here’s a screenshot:
2f875d9e017502437d91d8e41541cf096092fb67.png

#4

Okay, I got some other question.

Is there a difference between setting up collision in the FBX file, or placing blocking volumes concerning performance?

#5

All you need to do to get accurate collision for something like this where every polygon has collision is to “Use Complex Collision as simple” for geometry
1975d4b8e6326dde78f00ac3b6bff528385f95b3.png

#6

Well, that’s exactly what I needed, thanks a lot!

#7

I know with Maya, all you have to do is Duplicate the mesh and rename it to UCX_YourMeshName.

#8

I tried that before in Blender, but it didn’t really work for me. Maybe I did something wrong, dunno…

#9

That doesn’t work as far as Im aware because a collision mesh cant have any concave faces (I might be wrong).

#10

According to this page, you’re right. Just closed convex shapes.

#11

Sorry for the double post, but I got a more general question concerning this, since it’s a pretty big mesh. I often read that using such meshes is inefficient and that you should should split things up and such.
So, what do you think now? Can I just this one big mesh to serve as levelmesh or should I split it up? And how exactly then? Wall by wall or entire buildings? And what about the materials? One material per mesh, I read. How can I update them in UE4?
Just added some UV maps to a material, but it didn’t applied on the mesh.

Sorry for this whole bunch of questions. Looking forward to hear from you!

#12

Make the buildings a mesh, use the landscape tool for what the buildings will sit on. With the buildings, you can make them modular but you may run into lighting issues. I would just make any building that is connected or supposed to be standalone, a single mesh.

#13

Okay thanks for the advice. And what about materials? Take a simple hut for instance. It would have three materials: floor, walls and roof. Is this a problem, as the mesh would use three different materials? 'Cause I often read about having just one material in a single mesh, which would not really work with whole buildings…
I’m just a bit confused right, dunno what’s better, what saves performance or whatever.