★★★How to draw a spiral helix with variable pitch

Issue:

How to draw a spiral helix with variable pitch？

Solution:

1. Click the Wireframe → Spiral Helix command.
   
2. Select a Axis and Start Point.
3. Select the Constant in the Regulation type and input a radius.
4. Select the Height and pitch in the Length type and input a Start distance and End distance.
   
5. Select the Customize linear in the Regulation type of pitch.
6. Select the Point in the type, input a point and pitch
7. Press enter to get a point and the data is displayed in the list of points below. Repeat the 6th step to get all the data in the point list.
   
8. Point <0> coincides with the starting point of the helix.
   The pitch from point <0> to point <1> is 5.
   The pitch from point <1> to point <2> varies linearly from 5 to 30.
   The pitch from point <2> to point <3> is 30.
   The pitch from point <3> to point <4> varies linearly from 30 to 5.
   The pitch from point <4> to point <5> is 5.
   The <5> point coincides with the end point of the helix.