How to create a helix that follows a path curve.
Solution
1. Create the path curve that the helix will follow.
2. Create a datum plane at the end of the path:
a. Select 'Insert-->Datum/Point-->Datum Plane'.
b. Select the path curve.
c. Location on Curve/Location = Arc Length
d. % Arc Length = 0.0
e. Select 'Alternate Solution' until the plane normal is
tangent to the path curve.
NOTE: Usually, only takes one click on 'Alternate Solution'.
f. OK the Datum Plane dialog.
3. Create a Sketch on the Datum Plane:
a. Select 'Insert-->Sketch'.
b. Type = On Plane.
c. Select the Datum Plane.
d. OK the Create Sketch dialog.
4. Create a line in the sketch that represents the radius of the
helical shape. The line will start at the end point of the path
curve and go out horizontally the radius of the helix.
5. Select 'Finish Sketch'.
6. Select 'Tools-->Expression'.
7. Create the following expressions (using 'Type = Number' & 'Constant' unit).
t=1n
number_of_turns=8 (where 8 represents the number of desired turns).
ft=t*number_of_turns*360
8. OK the Expressions dialog.
9. Create a Swept feature:
a. Select 'Insert-->Sweep-->Swept'.
b. Select the sketched line (from step 4) as the section curve.
c. Select the path curve(s) (from step 1) as the Guide.
d. Use the default Alignment Method and Tolerance.
e. Orientation Method Orientation = Angular Law.
f. Law Type = By Equation.
g. Parameter = t
h. Function = ft
i. Scaling = Constant
j. Scale Factor = 1.0
k. OK the Swept dialog.
10. The outside edge of the helical surface is the needed path.
11. If only the edge is needed, the outside edge can be extracted as a
Composite Curve using 'Insert-->Associative Copy-->Composite Curve'.
NOTE: In the Composite Curve command, 'Associativity' can be toggled off
if the extracted curve does not need to be associative to the edge.
Notes and References
Hardware/Software Configuration
Platform: all
OS: n/a
OS Version: n/a
Product: NX
Application: DESIGN
Version: V7.5
Function: CURVE
Ref: 001-6992617