I don't think this is true.
local c0 = CFrame.new( 10,10,10 ) * CFrame.Angles( 1,1,1 ) -- note rotation local c1 = CFrame.new()
A = Workspace.A B = Workspace.B
j = Instance.new("Weld") j.Parent = A j.Part0 = A j.Part1 = B j.C0 = c0 j.C1 = c1
print( c0 * c1 ) -- part is positioned by c0 * c1 print( A.CFrame:inverse() * B.CFrame ) -- confirms this
See also description in Welds
--GoldenUrg 04:15, 28 April 2010 (UTC)