Topic: Arc direction?

[LE]

Thanks, I noticed that let me see if I can fix it.

[Jeff_M]

Alan, the only time I can get the result you do is when my point of selection of the tangent is on the 'downhill' side of the line from the perpendicular point, which is how I thought it would work......
FWIW, here is the original pic that the OP posted of what they are trying to do.

[CAB]

Jeff, I get that result no matter where I select on the line. Very curious?

[LE]

on the mean time, here are some formulas I did for one of my routines:

Arc angle

Code: [Select]

double arcAngle = ( 2.0 * atan( chord / 2.0 / sqrt(( pow(r,2) - pow(( chord / 2.0 ),2) ))) );

Arc length

Code: [Select]

#define PI 3.141592653589793238462643383279502884197169399375105820974944592308
#define PI360 6.283185307179586476925286766559
double arcLength = ((( ( arcAngle * 180.0 ) / PI ) / 360.0 ) * PI360 * r );

I do not have them as a lisp  

pow() is the same as expt function in lisp

[CAB]

Jeff, i would have expected these results, no?

[LE]

Jeff & Luis,
What happens when you use the following example with the routine Luis provided?
PS line is 25 or so units long.

Now I did the test and is running just fine.