Well you could get the direction from the player to the part and shoot a ray and check the normal
#Detect which face is closest to player
lost knot
local direction = (playerPosition - partPosition).Unit is to get the direction if im not mistaken
twilit walrus
Cast a ray to each side of the part and compare the distance between both to your character (the smaller distance being the face closer to you)
waxen flume
Cast a ray to each side of the part and compare the distance between both to you...
How do I cast a ray to a specific side?