Finding the exterior dimensions of a USB type-c receptacle
Width: 8.94mm
Width before the housing bends: 6.69mm (-0.055mm or +0.045mm)
Height: 3.26mm (+-0.15mm)
Height before the housing bends: 0.70mm (might be 0.6mm but with the bigger size, the bend will always be big enough. Now draw this in your preffered 2D or 3D modelling software and draw an arc between the lines before the bending. Make sure you place the lines beofre bending on the correct distances from eachother.

Black lines have length: 6.69mm horizontally
Blue lines have length: 0.70mm vertically 
Draw then the Arc, displayed in red in my sketch. 
This should be good enough for your project. If you need the exact measurements, then emailing the manufacturer is the only way, because after looking for 10 minutes through various sources and datasheets, there is nowhere a mention fo the radius of the bends. Perhaps someone else has a good source, but I didn't find anything.