Thanks for input appreciated here are a few tests I have carried out I created polyline with a vertical deviation of 0.7mm from which I could apply fillets and shell and the pipe software could still detect the bend info practically straight piece of pipe I have included a screenshot of the bend info. Once I put the curve deviation down to 0.6mm could no longer apply fillets which would back up the minimum 1 degree radius. In the reconstructed 3d polyline I have highlighted an out of range fillet node. Thanks for the info a getting a better idea of the limits to which I can push the pipe bending machine. I will play with applying 1 at a time rather then group application.