Collisions
Note: Since version 1.0.0.32 complex collision has become a lot more reliable. However, it's still best practice to use simple collision for reliable physics and better performance.
UE4 Documentation: FBX Static Mesh Pipeline
Youtube Video: UE4 - Tutorial - Custom Collisions!
This is a quick and effective way to create collsions, here we are selecting the top faces of our obstacles, separating each face and solidifying/extruding them downwards.
- Go to Orthographic Top View (Numpad 5, Numpad 7).
- Make sure X-ray mode is disabled.
- In Edit mode select all top faces with box select (B, click and drag).
- Once you have your selection you are free to move the camera and re-enable Xray mode.
- Duplicate your selection (Shift D + Right Click) and separate (P - Selection) so that they are a new Object.
- Parent the new Object to your obstacle mesh (Crtl + P) and rename it so that it has the
UCX_prefix. - Now's a good time to optimize the mesh if needed, apply/remove any modifiers, remove any unnessecary loop cuts and simplify the geometry as much as possible. Also ensure that all faces are convex and not concave (should not be a problem if they are tris or quads).
- In Edit mode with the new object, Select All (A) then Mesh > Split > Faces by Edges.
- In Object mode add a Solidify Modifier and adjust the thickness until it covers what it should.
- Then back in Edit mode go to Mesh > Separate > By loose parts.
- Batch rename the collision meshes find/replace
.0with_.
This is mostly useful for Handrails and flatbars, the basic idea is to re-create your obstacle using simple boxes. The 3d cursor, vertex snapping and edge snapping can be very useful when doing this.
Note: Each colour represents a separate collision mesh.
