Hi Veloce Modelli

In this case the triangle tolerance and agacency tolerance refer to the placement of the vertices and faces of the triangles relative to where they would go on a continuous non-flat surface.

For example, if you are representing a cylinder as a band of triangles, you would need an infinite number of triangles to perfectly recreate the cylinder. So the tolerance will indicate how far away a triangle's vertex can be from the surface in your design, ultimately determining how many triangles need to be used to represent it. Flat surfaces with corners can always be represented at 0 tolerance, this only applies to curved surfaces like fillets, cylinders and NURBs.

In this case 0.025 mm will work well for both tolerances, as it will give you a number of triangles that will fit within a fraction of the resolution of the FUD material.

The other question this raises is what units you are exporting in. It can be assumed that you will be exporting in the default dimension of your part in NX, but you should upload the exported STL and confirm that its bounding box units match the dimensions of your part, and change the units of the STL on shapeways if not.

Best,

William

Last edited: Mar 15, 2013