main/src/georegression/metric/Distance3D_F64.java
public static double distance( Cylinder3D_F64 cylinder, Point3D_F64 point ) {

		double r = Distance3D_F64.distance(cylinder.line,point);

		return r - cylinder.radius;
	}
public static double distance( Cylinder3D_F64 cylinder, Point3D_F64 point ) {

		double r = Distance3D_F64.distance(cylinder.line,point);

		return r - cylinder.radius;
	}
Returns the signed distance a point is from the cylinder's surface.  If the point is outside of the cylinder
it's distance will be positive.  If it is inside it will be negative.

@param cylinder The cylinder
@param point The point
@return Signed distance