[ODE] XODE - should angles be in degrees or radians?

[Bob Dowland]

> > But, not being able to store things like right angles precisely, 
> > would seem like a bit of a showstopper for a geom/phys file format. 
> 
> I believe this argument is a fallacy. The reason is that ODE, 
> internally, uses radians, so even if you can "store" a 90 degree angle 
> precisely, as soon as you "load" that into ODE, it's no longer exact.
> 

You're absolutely right! More to the point, when you save back out, that precise 90 degrees is toast (well lightly toasted anyway).

 - I was imagining a scenario in which a file containing a radian represented (90 degree) angle is opened and closed so often that it eventually corrupts itself. But, in fact, this could be far worse with a degree (ie non-"native") representation. 

Focusing on our 90 degree angle we could be seeing:

open file: 90 degrees -> (pi/2 + epsilon) rads
save file: (pi/2 + epsilon) rads -> (90 + moreepsilon) degrees
open file: (90 + moreepsilon) degrees -> (pi/2 + evenmoreepsilon) rads

and so on... 

	So in fact you could potentially corrupt the degrees representation by just opening and close/saving the file - oops!

Theres still the bin<->dec conversion for floats but we get that with either format.

Bob.





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