This command creates a conic section curve segment (hyperbola, parabola, ellipse or
circular arc) for given segment endpoints, given endpoint tangent lines intersection point,
and a parameter that defines the curve type.
Inputs
sx sy sz
Coordinates of conic curve segment start point.
ex ey ez
Coordinates of conic curve segment end point.
tx ty tz
Coordinates of a point at intersection between straight lines tangent to created conic
curve segment at start and end points.
ratio
Parameter that defines the created conic curve segment “altitude”. Consider the
segment that connects the tangents’ intersection point with the midpoint between the
start and end points of the curve. If the length of this segment is used as the unit
length, then the ratio is defined as the length of the portion of the segment that
connects the midpoint with the point where the segment is intersected by created curve
(see figure below). Valid values for ratio are in the range 0 to 1. For the value of
0.5, the conic curve is a parabolic segment. For the values between 0 and 0.5, the conic
curve is an ellipse. For the values between 0.5 and 1, the conic curve is a hyperbolic
segment.
A ratio of -1 can also be used to invoke automatic circle calculation. A circular arc
is then created, provided the length of the tangent segments are equal.Figure 1.
Examples
To create a parabolic segment with the start point at (1,2,3), the end point at (4,2,3) and
the endpoint tangent lines intersection point at (3,10,3):
*linecreateconic 1 2 3 4 2 3 3 10 3 0.5
To create a 90 degree circular arc that lies in the plane z=0 and connects points (0,0,0)
and (1,0,0):
*linecreateconic 0 0 0 1 0 0 0.5 0.5 0 -1.0
Errors
Incorrect usage results in a Tcl error. To
detect errors, you can use the catch
command:
