Create near perfect convex colliders

Introduction

This tutorial will show you how to make mesh colliders for your weapons that will fix the weapon almost perfectly. It won't take long and will improve the quality of your weapons greatly. This tutorial requires you to already have Blender installed.

Step by Step

1. Open Blender.
2. Import your model file by clicking File > Import > fbx (or, .obj or whatever floats your boat).
3. Click the mesh you want to cut on the right side of the screen.
4. Enter edit mode in the top left corner.
5. Press this little button to see all vertices instead of only the front (This makes it transparent).
6. Select vertices by hand which you want to separate (Tip: hold down shift key to keep your selection after letting go).
7. Right click and separate > selection.
8. Toggle the eye icon to hide and show your to see if your mesh was cut correctly. (Tip: if not, you can just undo by doing Ctrl+Z on Windows or Cmd+Z on Mac.)
9. Then finally after your meshes are all cut, export by clicking File > Export > fbx.