Warp <war### [at] tagpovrayorg> wrote:

> Kaveh <kav### [at] delete_thisfocalimagecom> wrote:
> > I find it easier just to use the curled fingers method, not the index
> > and third fingers. To get the sense of the z axis, I position the left
> > hand such that the four fingers curl from the x to the y axis. Then the
> > thumb shows the direction of the z axis.
> 
>   That description was very unclear. I did not visualize at all which
> direction the thumb is pointing at...

It was not clear, I agree. I will put it another way. Put your left hand
in the 'aerobics' position, with fingers curled. Now, point your thumb
in the +z direction. Now if you were to rotate the x axis to coincide
with the y, it your fingers are giving the correct direction.

In a right handed system, sometimes a screw is used. If the screw has
its tip in the +z direction, turning the screw from x to y pushes the
screw in the z direction. But this is of course opposite to the
left-handed system.

All easier to see of course than to describe. 

I just find it easier to have something real like a screw, than to
remember a mnemonic.

-- 
Kaveh

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