9.5.2

260 • CHAPTER 7
OBJECTS MENU • SPLINES • 261
Helix with 4 revolutions (left) and 3.5 revolutions (right).
For example, if the start angle is 0° and the end angle 720°, the helix makes two complete revolutions.
If the helix begins at 180°, there will be only 1.5 revolutions.
You can enter calculations into the boxes. In the above example you might
use 4*360 instead of 1440. For the avid mathematician, the number of spiral
threads is the results of the formula: (EndAngle – StartAngle) / 360°.
Height
This value denes the height of the helix in the Z direction. The pitch of the screw is the result of the
formula: Height / ((EndAngle – StartAngle) / 360°).
Radial Bias, Height Bias
The bias values give the speed with which the end values of the helix are to be reached. The radial
bias denes the speed of the horizontal growth, while the height bias determines the vertical growth.
See the examples below.
Three spirals with 10 spiral threads and an end
radius of 0; radial bias set to 10% (left), 50%
(center) and 90% (right).
Three spirals with 10 spiral threads; height bias
set to 10% (left), 50% (center) and 90% (right).