Possibly bad curve’s draft tangent

[SW]

I've created a style feature with a draft surface constraint in Wildfire 4. It seems alright but when I regenerate I get the message "Possibly bad curve's draft tangent created. Try invert it manually." I guess this is a bad thing, but can anyone shed any light on what this means and what I need to do to mend it?

Thanks,

Sam

 

[SW]

It seems as though the draft is in the wrong plane. The angle changes along the curve direction. Surely the draft angle should lie on a plane normal to the curve.

The parting line is curved in all directions as shown in the following image but I would have thought this should still be possible.




In the help it says:

Note:
For draft to plane, the endpoint of the curve should be a soft-point to any
other curve. For draft to surface, the endpoint of the curve must be a
soft-point onto the surface boundary or a COS.

I can get round it by using a separate sweep feature to define the draft angle, but this is not ideal. Anyone got any idea what I'm doing wrong?




Thanks,

Sam

Edited by: SW