Extrudes a 2D shape along the path of a sphere spiral.

When using this module, you should use points to represent the 2D shape. If your 2D shape is not solid, indexes of triangles are required. See polysections for details.

Dependencies: `rotate_p`

, `sphere_spiral`

, `cross_sections`

, `polysections`

.

## Parameters

`shape_pts`

: A list of points represent a shape. See the example below.`radius`

,`za_step`

,`z_circles`

,`begin_angle`

,`end_angle`

,`vt_dir`

,`rt_dir`

: See sphere_spiral for details.`twist`

: The number of degrees of through which the shape is extruded.`scale`

: Scales the 2D shape by this value over the length of the extrusion. Scale can be a scalar or a vector.`triangles`

:`"SOLID"`

(default),`"HOLLOW"`

or user-defined indexes. See polysections for details.

## Examples

```
include <rotate_p.scad>;
include <cross_sections.scad>;
include <polysections.scad>;
include <sphere_spiral.scad>;
include <sphere_spiral_extrude.scad>;
function shape_pentagram(r) =
[
[0, 1], [-0.224514, 0.309017],
[-0.951057, 0.309017], [-0.363271, -0.118034],
[-0.587785, -0.809017], [0, -0.381966],
[0.587785, -0.809017], [0.363271, -0.118034],
[0.951057, 0.309017], [0.224514, 0.309017]
] * r;
points_triangles = shape_pentagram(2);
sphere_spiral_extrude(
shape_pts = points_triangles,
radius = 40,
za_step = 2,
z_circles = 20,
begin_angle = 90,
end_angle = 450,
vt_dir = "SPI_UP",
scale = 5
);
```