Essentially, what I’m trying to achieve is finding the closest possible Vector3 position of a part from the character. These parts can range in different sizes and rotations.

The best way to do this is to transform your reference point on the character (e.g. the position of the RootPart) into the local space of the part, then do a simple closest point on AABB check by clamping the position according to the part’s size, and finally transform it back into world space. Here’s some code:

local function ClosestPointOnPart(Part, Point)
local Transform = Part.CFrame:pointToObjectSpace(Point) -- Transform into local space
local HalfSize = Part.Size * 0.5
return Part.CFrame * Vector3.new( -- Clamp & transform into world space
math.clamp(Transform.x, -HalfSize.x, HalfSize.x),
math.clamp(Transform.y, -HalfSize.y, HalfSize.y),
math.clamp(Transform.z, -HalfSize.z, HalfSize.z)
)
end