jfmiller <jfm### [at] hotmailcom> wrote:

> Let me try (A degree in physics must be useful somewhere)
> 
> For a LEFT handed Coord. sys.
> 
> 1)  Place the 4 fingers of you LEFT hand so they point in the +X direction.
> In the default configuration of POVRay this is heading off the Right side of
> your moniter.
> 
> 2)  "Curl" your fingers so they move from +X to +Y.  Again Default POVRay:
> "curl" from right to top of your moniter
> 
> 3) Your thumb now points in the direction of the +Z axis.  In the example
> above "into" the screen.

Correct. Thank you for the clarification. :-)

Having thought about it, for me at least, a right-handed system would be
easier to use. I remember I never liked mnemonics. The 3-finger system
is really a mnemonic, whereas using the screw analogy (at least in my
simple mind) seems to have some physical basis to it.

Also, all vector calculus I learned was right-handed. If I remember
rightly, the vector A x B, gives a vector C whose direction is given by
using the right handed rule or screw rule, going from A to B. 

In physics, When a current goes through a wire, you get a magnetic
field, going around it in a right handed way, although I think this is
just a matter of convention.

So, in short, everything I have come across has used the right-handed
screw analogy, except POVray. As I am not comfortable with a left-handed
screw, I now have to use my left hand.

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