Apply a decal to the side of a part when clicked

[MrPieFace10 (typ)]

i want to create a system to apply blood decals to bodyparts after they get attacked but i dont really know how lol

[bIorbee]

if you can get the normal of the hit point then you can get the face of that part using this function

function GetNormalFromFace(part, normalId)
    return part.CFrame:VectorToWorldSpace(Vector3.FromNormalId(normalId))
end

function NormalToFace(normalVector, part)

    local TOLERANCE_VALUE = 1 - 0.001
    local allFaceNormalIds = {
        Enum.NormalId.Front,
        Enum.NormalId.Back,
        Enum.NormalId.Bottom,
        Enum.NormalId.Top,
        Enum.NormalId.Left,
        Enum.NormalId.Right
    }    

    for _, normalId in pairs( allFaceNormalIds ) do
        -- If the two vectors are almost parallel,
        if GetNormalFromFace(part, normalId):Dot(normalVector) > TOLERANCE_VALUE then
            return normalId -- We found it!
        end
    end
    
    return nil -- None found within tolerance.
end