Over 1.108.000 registered users (EN+CZ).
AutoCAD tips, Inventor tips, Revit tips, Civil tips, Fusion tips.
Try the updated Units converter and the new precise Engineering calculator.
New AutoCAD 2026 commands and sys.variables and env.variables,.
CAD tip # 9038:
Question
A
The Equation Curve function (parametric 3D sketch) can be used also to generate double helix (helix on helix), e.g. to make a model of a twisted-pair cable.
An example:

Fot the equation curve, use e.g. the following parameters:
x(t) = cos(1 rad*t*PI)*100+cos(1 rad*t*PI)*5*cos(10 rad*t*PI)
y(t) = 5*sin(10 rad*t*PI)+80*t
z(t) = sin(1 rad*t*PI)*100+sin(1 rad*t*PI)*5*cos(10 rad*t*PI)
tmin = 0 ul
tmax = 6 ul

Using this 3D sketch and sweeping of a circular profile (2D sketch) perpendicular to the curve you can make one wire. The second wire (with different color) is only rotated and offset. The rotation angle is 180/"twists per loop" (here: 18) and the offset in the Z axis is "half-loop pitch"/"twists per loop" (here: 8).
Similarly you can create also other types of 3D models, e.g. cooling pipes, etc.
Inv2013
17.1.2013
22292×
this tip shared by ARKANCE experts applies to: Inventor 2013 ·
![CAD Forum - tips, tricks, discussion and utilities for AutoCAD, Inventor, Revit and other Autodesk products [www.cadforum.cz] CAD Forum - tips, tricks, discussion and utilities for AutoCAD, Inventor, Revit and other Autodesk products [www.cadforum.cz]](../common/arkance_186.png)

