ROSETTA

The function slice performs a section of a given shape by a specified section plane. The section plane is specified by a point on the plane and a vector that indicates what portion of the shape we wish to delete.

Parameters:

s – Shape to be sectioned
p – Point on section plane
v - Vector

Syntax:

(slice s [p (u0)] [v (uz)])

Example:

> (slice (sphere (xy 0 0) 1) (xy 0 0) (z 1))
#<slice 1>

The function slice-with-surface performs a section of a given shape by a specified surface.

Parameters:

shape – Shape to slice
surface – Surface section

Syntax:

(slice-with-surface shape surface)

Example:

>(slice-with-surface (sphere (xyz 0 0 0) 10)
                    (surface-grid
                     (map-division
                      (lambda (u v)
                        (+xyz (u0) u  v (* (sin u) (cos v))))
                      -10 10 20
                      -10 10 20)))
'(#<slice 2> #<slice 3>)

The function extrusion performs an extrusion of a given shape by specifying the extrusion direction or extrusion height. If the given shape is a curve the end result will be a surface. If omitted, the extrusion height will be 1 and the extrusion direction will be parallel to the Z axis. If the shape is a surface the result will be a solid. The extrusion of extremely complex shapes is limited and specific to each CAD application.

Parameters:

shape – Shape to extrude (curve or surface)
h – Extrusion height

shape – Shape to extrude (curve or surface)
v – Extrusion direction

Syntax:

(extrusion shape [h 1])
(extrusion shape [v (uz)])

Example:

> (extrusion (surface-circle (xy 0 0) 1) 9)
#<extrusion 1>

> (extrusion (surface-circle (xy 0 0) 1) (xyz 2 3 9))
#<extrusion 1>

The function sweep performs an extrusion of a given shape along a specified path (spline or polygonal line). In AutoCAD this operation can take two additional parameters for changing the twist and scale along the extrusion. The extrusion of extremely complex shapes is limited and specific to each CAD application.

Parameters:

p – Extrusion path (spline or polygonal line)
shape – Shape to extrude
t – Twist along a path
s – Scale change along path

Syntax:

(sweep p shape [t 0] [s 1])

Example:

> (sweep (arc (xy 0 0) 2) (surface-circle (xy 0 0)))
#<sweep 2>

> (sweep
 (line (u0) (z 30))
 (surface-polygon (xy -1 -1) (xy 1 -1) (xy 1 1) (xy -1 1))
 2pi 2)
#<sweep 2>

The function revolve creates surfaces or solids of revolution specified the shape to perform the revolution, two pint that define the revolution axis, the initial angle and angle increment for the revolution. If omitted, the first point of the revolution axis will be considered the UCS origin, the second point will be considered immediately above the first one, the first angle 0 radians and the angle increment 2π radians.

Parameters:

shape – Shape to revolve (curve or surface)
p1 – First point of revolution axis
p2 – Second point of revolution axis
a1 – Initial revolution angle
da – Angle increment for revolution

Syntax:

(revolve shape [p1 (u0)] [p2 (z 1)] [a1 0] [da 2pi])

Example:

> (revolve
 (spline (xyz 0 0 2) (xyz 1 0 -1) (xyz 2 0 1)
         (xyz 3 0 -1) (xyz 4 0 0) (xyz 5 0 -1))
 (u0)
 (uz)
 (* 1/4 2pi) (* 3/4 2pi)) 
#<revolve 1> 

The function loft creates a smooth interpolation of a number of given curves or surfaces. The interpolation of curves will produce a surface and the interpolation of surfaces will produce a solid.

Parameters:

(list s1, s2, s3, s4, …, sn) – List of shapes for interpolation (curves or surfaces)

Syntax:

(loft (list s1 s2 s3 s4 … sn))

Example:

> (let ((circ0 (surface-circle (xyz 0 9 0) 4))
      (circ1 (surface-circle (xyz 0 9 2) 2))
      (circ2 (surface-circle (xyz 0 9 4) 3)))
  (loft (list circ0 circ1 circ2)))
#<loft-surfaces 3>

The function ruled-loft creates a ruled interpolation of a number of given curves or surfaces. The interpolation of curves will produce a surface and the interpolation of surfaces will produce a solid.

Parameters:

(list s1, s2, s3, s4, …, sn) – List of shapes for interpolation (curves or surfaces)

Syntax:

(ruled-loft (list s1 s2 s3 s4 … sn))

Example:

> (let ((circ0 (surface-circle (xyz 0 9 0) 4))
      (circ1 (surface-circle (xyz 0 9 2) 2))
      (circ2 (surface-circle (xyz 0 9 4) 3)))
  (ruled-loft (list circ0 circ1 circ2)))
#<loft-surfaces 3>

The function guided-loft The function guided-loft creates an interpolation of a number of given curves or surfaces with a greater level of control by specifying a set of “guide” lines. The interpolation of curves will produce a surface and the interpolation of surfaces will produce a solid.

Parameters:

(list s1, s2, s3, s4, …, sn) – List of shapes for interpolation (curves or surfaces)
(list g1, g2, g3, g4, …, gn) – List of guide lines

Syntax:

(guided-loft (list s1 s2 s3 s4 … sn) (list g1 g2 g3 g4 … gn))

Example:

(define (guides p0s p1s)
  (if (null p0s)
      (list)
      (cons (line (car p0s) (car p1s))
            (guides (cdr p0s) (cdr p1s)))))

> (guided-loft
 (list
  (surface-regular-polygon 6 (xyz 3 0 0) 1.0 0 #t)
  (surface-regular-polygon 3 (xyz 3 0 5) 0.5 (/ pi 6) #t))
 (guides
  (regular-polygon-vertices 3 (xyz 3 0 0) 1.0 0 #t)
  (regular-polygon-vertices 3 (xyz 3 0 5) 0.5 (/ pi 6) #t)))