Utilities

Defined in src/tessUtils.scad. These work with any list of points or polygons, not only the ones the tiling functions return.

generic_poly

generic_poly(vertices, paths, centers = undef, color_scheme = undef, alpha = 1,
             extrude = undef)

Draws one polygon for each entry in vertices.

Parameter	Meaning
vertices	List of polygons, each a list of [x, y] points
paths	Passed to polygon() for every polygon; the order in which to join the points
centers	One centre per polygon, used only to choose its colour
color_scheme	Name of a colour scheme; see get_gradient_color
alpha	Opacity from 0 to 1, applied only when a colour scheme is in use
extrude	Height to extrude each polygon to; omit for 2D geometry

Colour is applied only when both centers and color_scheme are given. Each centre is normalised to the bounding box of centers, and the result is passed to get_gradient_color(). Polygon i takes its colour from centers[i], so the two lists must correspond.

use <tessella/tess.scad>

centers = squares_centers_rect(10, 4, 3);

generic_poly(
    vertices = squares_vertices(9, centers),
    paths = [[0, 1, 2, 3, 0]],
    centers = centers,
    color_scheme = "scheme4",
    alpha = 0.6,
    extrude = 3
);

Rendering has more.

print_points

print_points(points, text_size = 1, color = [0.1, 0.1, 0.1], pointD = undef,
             point_color = [0.1, 0.1, 0.1], fn = 8)

Labels each point with its coordinates and marks it with a sphere.

Parameter	Meaning
points	List of [x, y] points
text_size	Size of the label text
color	Colour of the label
pointD	Radius of the marker sphere
point_color	Colour of the sphere
fn	Number of facets of the sphere

The label is centred 2 * pointD beyond the point in Y and raised 2 * pointD in Z, so it clears the marker.

use <tessella/tess.scad>

print_points(
    hexagons_centers_radial(10, 2),
    text_size = 1.5,
    color = "Black",
    pointD = 0.5,
    point_color = "Red"
);

Known issues

• pointD defaults to undef but is needed to position the label. Without it OpenSCAD reports undefined operation and Unable to convert translate(...) warnings for every point. Always pass it.
• pointD is used as the sphere’s radius, though its name and source comment say diameter.

filter_center_points

filter_center_points(centers, filter_list, tolerance = EPSILON)

Returns centers without the points that match any point in filter_list.

Parameter	Meaning
centers	List of points to filter
filter_list	List of points to remove
tolerance	How far apart two coordinates can be and still match

The order of the remaining points is kept. Points in filter_list that match nothing are ignored.

use <tessella/tess.scad>

echo(filter_center_points([[0, 0], [10, 0], [20, 0]], [[10, 0.0002]]));
// ECHO: [[0, 0], [20, 0]]

Removing tiles covers the workflow.

is_point_in_list

is_point_in_list(point, list, tolerance = EPSILON)

Returns true if point matches any point in list.

points_equal

points_equal(p1, p2, tolerance = EPSILON)

Returns true if every coordinate of p1 is within tolerance of the same coordinate of p2. The comparison is per coordinate, not a distance, and uses as many coordinates as p1 has.

use <tessella/tess.scad>

echo(points_equal([0, 0], [0, 0.0005]), points_equal([0, 0], [0, 0.002]));
// ECHO: true, false

get_gradient_color

get_gradient_color(normalized_x, normalized_y, color_scheme)

Returns an [r, g, b] colour for a position within a pattern.

Parameter	Meaning
normalized_x	Position along X, from 0 to 1
normalized_y	Position along Y, from 0 to 1
color_scheme	"scheme1" to "scheme6"

color_scheme	Red	Green	Blue
"scheme1"	x	1 − x	y
"scheme2"	1 − y	x	y
"scheme3"	y	1 − y	x
"scheme4"	1 − x	x	1 − y
"scheme5"	x	x · y	1 − x
"scheme6"	1 − x·y	y	x

Any other value returns light grey, [0.9, 0.9, 0.9].

use <tessella/tess.scad>

echo(get_gradient_color(0.25, 0.5, "scheme1"));
// ECHO: [0.25, 0.75, 0.5]

EPSILON

EPSILON = 1e-3;

The default tolerance for the point comparisons. It is a top-level variable, so it is visible in your file only with include <tessella/tess.scad>. With use, the functions still default to it; to change the tolerance, pass tolerance to the function.