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Added offset_paths() to sweep.scad.

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show_path() now takes an optional radius.
This commit is contained in:
Chris Palmer 2024-04-21 08:47:44 +01:00
parent 7a395e475e
commit a5b2018008
2 changed files with 21 additions and 16 deletions
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3
readme.md
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@ -7451,6 +7451,7 @@ Each vertex, apart from the first and the last, has an associated radius and the
| `cap(facets, segment = 0, end)` | Create the mesh for an end cap |
| `circle_points(r = 1, z = 0, dir = -1)` | Generate the points of a circle, setting z makes a single turn spiral |
| `helical_twist_per_segment(r, pitch, sides)` | Calculate the twist around Z that rotate_from_to() introduces |
| `offset_paths(path, offsets, twists = 0)` | Create new paths offset from the original, optionally spiralling around it |
| `rectangle_points(w, h)` | Generate the points of a rectangle |
| `rounded_path(path)` | Convert a rounded_path, consisting of a start coordinate, vertex / radius pairs and then an end coordinate, to a path of points for sweep. |
| `rounded_path_vertices(path)` | Show the unrounded version of a rounded_path for debug |
@ -7462,7 +7463,7 @@ Each vertex, apart from the first and the last, has an associated radius and the
### Modules
| Module | Description |
|:--- |:--- |
| `show_path(path)` | Show a path using a chain of hulls for debugging, duplicate points are highlighted. |
| `show_path(path, r = 0.1)` | Show a path using a chain of hulls for debugging, duplicate points are highlighted. |
| `sweep(path, profile, loop = false, twist = 0, convexity = 1)` | Draw a polyhedron that is the swept volume |
![sweep](tests/png/sweep.png)

34
utils/sweep.scad
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@ -111,7 +111,7 @@ function helical_twist_per_segment(r, pitch, sides) = //! Calculate the twist ar
//
// Generate all the transforms for the profile of the swept volume.
//
function sweep_transforms(path, loop = false, twist = 0) =
function sweep_transforms(path, loop = false, twist = 0, initial_rotation = undef) =
let(len = len(path),
last = len - 1,
@ -122,7 +122,7 @@ function sweep_transforms(path, loop = false, twist = 0) =
lengths = [for(i = 0, t = 0; i < len; t = t + norm(path[min(i + 1, last)] - path[i]), i = i + 1) t],
length = lengths[last],
rotations = [for(i = 0, rot = fs_frame(tangents);
rotations = [for(i = 0, rot = is_undef(initial_rotation) ? fs_frame(tangents) : rot3_z(initial_rotation);
i < len;
i = i + 1,
rot = i < len ? rotate_from_to(tangents[i - 1], tangents[i]) * rot : undef) rot],
@ -169,7 +169,7 @@ function sweep(path, profile, loop = false, twist = 0) = //! Generate the point
points = skin_points(profile, path, loop, twist),
skin_faces = skin_faces(points, npoints, facets, loop),
faces = loop ? skin_faces : concat([cap(facets)], skin_faces, [cap(facets, npoints - 1)])
) [points, faces];
) [points, faces];
module sweep(path, profile, loop = false, twist = 0, convexity = 1) { //! Draw a polyhedron that is the swept volume
mesh = sweep(path, profile, loop, twist);
@ -229,16 +229,20 @@ function rounded_path(path) = //! Convert a rounded_path, consisting of a start
function segmented_path(path, min_segment) = [ //! Add points to a path to enforce a minimum segment length
for(i = [0 : len(path) - 2])
let(delta =
assert(path[i] != path[i + 1], str("Coincident points at path[", i, "] = ", path[i]))
path[i+1] - path[i],
segs = ceil(norm(delta) / min_segment)
)
for(j = [0 : segs - 1])
path[i] + delta * j / segs, // Linear interpolation
path[len(path) - 1]
let(delta =
assert(path[i] != path[i + 1], str("Coincident points at path[", i, "] = ", path[i]))
path[i+1] - path[i],
segs = ceil(norm(delta) / min_segment)
)
for(j = [0 : segs - 1])
path[i] + delta * j / segs, // Linear interpolation
path[len(path) - 1]
];
function offset_paths(path, offsets, twists = 0) = let( //! Create new paths offset from the original, optionally spiralling around it
transforms = sweep_transforms(path, twist = 360 * twists, initial_rotation = 0)
) [for(o = offsets) let(initial = [o.x, o.y, o.z, 1]) [for(t = transforms) initial * t]];
function spiral_paths(path, n, r, twists, start_angle) = let( //! Create a new paths which spiral around the given path. Use for making twisted cables
segment = twists ? path_length(path) / twists / r2sides(2 * r) : inf,
transforms = sweep_transforms(segmented_path(path, segment), twist = 360 * twists)
@ -246,16 +250,16 @@ function spiral_paths(path, n, r, twists, start_angle) = let( //! Create a new p
function rounded_path_vertices(path) = [path[0], for(i = [1 : 2 : len(path) - 1]) path[i]]; //! Show the unrounded version of a rounded_path for debug
module show_path(path) //! Show a path using a chain of hulls for debugging, duplicate points are highlighted.
module show_path(path, r = 0.1) //! Show a path using a chain of hulls for debugging, duplicate points are highlighted.
for(i = [0 : len(path) - 2]) {
hull($fn = 16) {
translate(path[i])
sphere(0.1);
sphere(r);
translate(path[i + 1])
sphere(0.1);
sphere(r);
}
if(path[i] == path[i + 1])
translate(path[i])
color("red") sphere(1);
color("red") sphere($fn = 16, r * 4);
}