[Radiance-general] rtrace -oo adds direction to origin

[Greg Ward]

> Let me repeat this:
> - rtrace -defaults: -i- (so illuminance is off, hence luminance)

Also defaults to -I-.  These are separate options, and need to be  
considered independently, though their behavior is somewhat similar.

> - -i/-I is a boolean switch (or are they two independent boolean  
> switches?)

Independent.

> - I have -I in my rtrace command line. This toggles the default,  
> turning
> it on.

That's right.  Two -I options would turn it off again.

> - with i/I set to on, the origin should be set to the input, no?

WIth -i the origin will match the input, as the rays are traced from  
there.  With -I, the origin will not match the input, as I said.

> I think I understand the subtlety of measuring luminance vs.  
> illuminance,
> so the added '1' and the inversed direction doesn't worry me. The
> 'toggling' is, though.

Again, -i and -I do not toggle each other.  With -I+ set (either  
using -I alone or -I+), the -i setting become irrelevant.  Think of - 
I as superseding the -i setting.

-Greg