Documentation for SpiralPath Plugin
by 
Prem Subrahmanyam (prems@noblestar.net)

Legal Stuff:

This plugin is distributed as freeware and is hence released into the
public domain.  The author makes no warranty whatsoever regarding the
fitness or usability of this product for any purpose and is not responsible
for any damages whatsoever resulting from the use of this product.  In other
words, use this product at your own risk.  

That said, here is a nifty little spiral path generator that I whipped up
while learning the Lightwave plugin API.  It gives one the ability to create 
helices, shell type spirals, etc. easily.  I am running Lightwave 5.0 on an
Intel box under Win95, hence it will only work on another Intel box running
Lightwave 4.0 or 5.0.  I assume it will run under Win3.11 as well as 95 or NT, 
but I can't guarantee that).  

Installation:
To install this plugin, simply copy it to your plugins\modeler directory, 
run modeler, choose Object->Custom->Add Plugin and select the spiral.p 
plugin file.  You should then see SpiralPath under your Object->Custom 
requester.  

Running SpiralPath:
When you invoke the SpiralPath plugin, you will see a requestor with the
following fields:
   
   Axis: Select the X, Y, or Z axis as the central axis for the spiral

   Number of Segments: Select how many segments you would like in the spiral

   Degrees to rotate: Specify the number of degrees you want the spiral to 
   rotate, with 360 completing one rotation.  For example, to make 3 
   rotations, you would specify 1080 as the number of degrees.

   Length Delta Along Axis: Specify the length (in meters) that the spiral
   will move along the spiral axis per segment.  By default this is zero;
   this is useful in making helical spirals, off-axis shells, springs, 
   curly cords, etc.

   Length Delta Scaling Factor: This factor is multiplied against the
   length delta per segment.  It is useful for generating shells where
   they grow in spacing per whorl.

   Starting Radius: Specify the starting radius in meters.

   Radius Delta Scaling Type: Specify whether the "Radius Delta per
   Segment" is added to or multiplied against the radius.  Additive
   causes the same radius delta to be added at each segment.  
   Multiplicative will cause the factor to be multiplied against the
   radius for each segment--essential for creating shell-type spirals.

   Radius Delta per Segment: See above.


Tutorials:

#1: 
Try the following Settings:
Axis:                      Y
Number of Segments:        20
Degrees to Rotate:         1080
Length Delta Along Axis:   0.5
Axis Delta Scaling Factor: 1.0
Starting Radius:           1.0
Radius Delta Scaling Type: Additive
Radius Delta per Segment:  0.0

Result: A helical coil path
    
#2: 
Try the following settings:
Axis:                      Y
Number of Segments:        20
Degrees to Rotate:         720
Length Delta Along Axis:   0
Axis Delta Scaling Factor: 1.0
Starting Radius:           1.0
Radius Delta Scaling Type: Multiplicative
Radius Delta per Segment:  1.1

Result: a spiral similar to a nautiloid-type shell

#3: 
Use the same coil as in Tutorial #2
Copy and Paste this coil into another layer
Scale the second coil by 0.5 around 0,0,0
Create a ball in a third layer with the following parameters:
   Globe
   Sides:16
   Segments:8
   Center: 0 m, 8.6342 mm, 704.1709 mm
   Radii: 0 m, 378.9174 mm, 794.0142 mm
Now, with the other two coils selected in the background, perform
a rail extrude with the default parameters.

Result: A nice nautilus shell.