This is the process I take to make sure my rigs work correctly:
- Set your scenes units to metric with scale of 1
- Import your model into blender (unless you already have one made in blender)
- Add 1 bone enter edit mode
- Scale and rotate bones to the correct size while in edit mode if you have the wrong scale or rotation on your bones in edit mode they will reflect that in ue4 but not blender(this step can make or break a proper bind to your mesh)
- Once you have your rig to the correct size and rotation within edit mode, it’s then time to bind your rig to your mesh, next enter object mode, and select your mesh and rig and hit ctrl+p bind with automatic weights
- Fine tune with weight painting where necessary
- Select your rig go into pose and select each bone, enter object mode and select the rig and mesh
- Export fbx with following settings: only settings that need to be changed from the default are Z up and the forward axis should match which direction your rig and mesh are facing, check “selected objects”, highlight mesh and armature set scale to 1
- Hit export
- Go into your project’s content browser make a new folder that represents your animations
- Click import and and select your fbx
- I don’t change any of the default settings when importing (I don’t use toa ref pose) hit import all
- Cheers you now should have a working skeletal mesh or rig or both
Hope this helps 