
This is a quick help file for the POVLAB plugin "helix.exe" by Robert
Hodkinson.

POVLAB 3.2 and later is needed to use this plugin.

Some brief explanations for those of you that are slightly confused over the
terms i have used in the interface you see within POVLAB.

All of the options here can be used in _any_ combination.

NOTE: please note where non integer values are not acceptable (pretty
      obvious when you think about it), if non integer values are entered,
      the fractional part will be discarded.


Helix Radius Start: (integer and floating)
----------
This is the starting radius of the helix.


Helix Radius End: (integer and floating)
--------
This is the ending radius of the helix.


Helix Length: (integer and floating)
-------------
This is the total length of the helix.  If a +ve number is given the
Helix is created from 0 in the Y axis, to the +ve value given.  If a -ve
value is given a Helix is created from 0 in the Y axis to the -ve value
given.


Objects per Rev: (integer)
----------------
This is the total number of objects to use per 360 degree revolution in a
single arm of the Helix.


Length per Rev: (integer and floating)
---------------
This is the length taken for the helix to complete one 360 degree revolution.

eg.  if 'helix length' = 10, 'length per rev' = 20, 'objects per rev' = 40,
     a one half revolution of a helix will be made containing 20 objects.


Helix offset X, Helix offset Y, Helix offset Z: (integer and floating)
-----------------------------------------------
This is to enable the helix to be moved about in three dimentional space.


Helix Rotate Y: (integer and floating)
---------------
This is to enable rotation of the _entire_ helix being created.


Object No start: (integer)
----------------
This is to enable a non zero numbered object to be chosen as the first
object created in the helix.


Scale object X, Scale object Y, Scale object Z: (integer and floating)
-----------------------------------------------
This enables you to scale the object within the helix.


Rotate object X, Rotate object Y, Rotate object Z: (integer and floating)
--------------------------------------------------
This enables you to rotate each object within the helix.


Sphere/Cube object: (one choice only)
-------------------
This is the current list of objects that can be used as helix elements.


Single/Double/Triple/Quadruple/Quintiple/Hextaple Helix: (one choice)
--------------------------------------------------------
These are the number of helix elements that can be used to create the helix.
A double helix will create the familiar DNA shape.


Clockwise/Anticlockwise: (one choice)
------------------------
This is where you can decide weather your helix rotates in the clockwise
or anticlockwise direction.

eg. If a +ve helix length and clockwise options are chosen.  Then the helix
is created clockwise when looking down from the +ve Y axis, if a -ve length
and the clockwise option is chosen the helix is created anticlockwise!


Face object inwards: (check or un-check)
--------------------
If you wish all the objects within the helix to face towards the center of
the helix, check this option (the same face of each object will face the
center of the helix).


Random notes and hints.
-----------------------
To create a straight cylinder start and end radius are the same.

To create s cone helix, start and end values need to be different.

You can create a double cone (points touching) by having one -ve radius and
one +ve radius.

At the moment of writing a 'flat' spiral of objects (0 helix length) is not
possible, the helix length has to be slightly greater or less than zero.
eg. 0.000001 will work.

If you create a helix with many objects, then butt up another helix of
objects, the join will not be perfect because of rounding errors, you can
compensate this by fiddling with the 'Helix Rotate Y' option.

END OF FILE.









