If you start from scratch (new scene being opened and everything cleared off the scree) all you have to do is set the Unit Scale to .01, length to metric, and then adjust the clip distance in the N options menu. Then off you go. Start modeling, cause everything will use the new unit scale when being created. If you already have a character and you haven’t started rigging yet, set the Unit Scale to be .01, then scale the character by a 100 if he’s tiny (which he usually is) then start rigging.
That’s why I like to use the UE4 Tools add on before I start rigging and animating a character in blender. I just click the set scene size button and that takes care of the stuff for me instead of setting it manually (besides the clip distance maybe). Again though if I modeled the character before i set the scene unit scale, the character might be too small. so I do a scale by 100, apply and then start rigging.
The problems only occur when you start rigging, then realize your scene isn’t the size it should be, then try to scale up the character and rig by 100 after that. It’s only happened to me once (then i started using the add on and started the rig over since i need the practice) so i don’t know too many of the issues that might arise after rigging and needing to scale it to fit the unit scale. Animations screwed up for me so i had to start over since i didn’t know what else to do. Now that i think back i probably could’ve just re key framed it and been fine, but too late to try it now lol.
I believe I should’ve mentioned all the oversights that might occur now.