hello, is there a way to draw a helix (NX11) with variable pitch controlled at given points? I need to have 8 turns, first 2 turns with pitch1, 3rd with pitch2, 4th and5th with pitch3, 6th pitch2, 7th 8th with pitch 1.
I have tried with the option 'linear along a spine', but I only get the first two precise, the others are not (see red arrows, image below). I also tried 'by law curve' but didn't get the expected result.
Thank you for good tips!
Solved! Go to Solution.
I have not really used the Helix feature before, but I have been doing a lot of helix-like geometries by writing equations for x,y and z values and using Larve Curve, by equation. This get quite complicated when dealing with non-constant pitch etc.
But I tried the helix function now. To me the option "linear along spine" for pitch and radius does not make any sense at all. I think NX is doing something else, approximating the linear behavior. If the resulting curve is to be not only continues but also differential (G1 behavior all along the curve), the radius and pitch must be differential too. And a linear behavior between more than two points is not differential.
So this assumed approximation is probably why you don't get precise results. You requirements for the pitch can't describe a pitch at one turn, and then another pitch at the next turn. The curve would not be G1 and could not be used for e.g. Swept feature.
Hope this makes sense.
Yes, that is the perfect explanation of what I 'felt'... I think the best way to get what I need is to use the Wrap Curve command, wrapping a spline through points around a cylinder.
Thank you Erland