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use projection before calling is_path_simple in rouinded_prism

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rewrite vnf_bend so it doesn't rely on pseudo 3d polygon self-intersection
This commit is contained in:
Adrian Mariano 2021-10-05 16:14:36 -04:00
parent d986db2e1e
commit 0093d10993
2 changed files with 1368 additions and 1400 deletions
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4
rounding.scad
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@ -1931,8 +1931,8 @@ function rounded_prism(bottom, top, joint_bot=0, joint_top=0, joint_sides=0, k_b
top_patch[i][4][4]
]
],
top_simple = is_path_simple(faces[0],closed=true),
bot_simple = is_path_simple(faces[1],closed=true),
top_simple = is_path_simple(project_plane(faces[0],faces[0]),closed=true),
bot_simple = is_path_simple(project_plane(faces[1],faces[1]),closed=true),
// verify vertical edges
verify_vert =
[for(i=[0:N-1],j=[0:4])

158
vnf.scad
View File

@ -709,9 +709,11 @@ function _triangulate_planar_convex_polygons(polys) =
// Usage:
// bentvnf = vnf_bend(vnf,r,d,[axis]);
// Description:
// Given a VNF that is entirely above, or entirely below the Z=0 plane, bends the VNF around the
// Y axis, splitting up faces as necessary. Returns the bent VNF. Will error out if the VNF
// straddles the Z=0 plane, or if the bent VNF would wrap more than completely around. The 1:1
// Bend a VNF around the X, Y or Z axis, splitting up faces as necessary. Returns the bent
// VNF. For bending around the Z axis the input VNF must not cross the Y=0 plane. For bending
// around the X or Y axes the VNF must not cross the Z=0 plane. Note that if you wrap a VNF all the way around
// it may intersect itself, which produces an invalid polyhedron. It is your responsibility to
// avoid this situation. The 1:1
// radius is where the curved length of the bent VNF matches the length of the original VNF. If the
// `r` or `d` arguments are given, then they will specify the 1:1 radius or diameter. If they are
// not given, then the 1:1 radius will be defined by the distance of the furthest vertex in the
@ -776,6 +778,11 @@ function _triangulate_planar_convex_polygons(polys) =
// #vnf_polyhedron(vnf1);
// bent1 = vnf_bend(vnf1, axis="Z");
// vnf_polyhedron([bent1]);
// Example(3D): Bending more than once around the cylinder
// $fn=32;
// vnf = apply(fwd(5)*yrot(30),cube([100,2,5],center=true));
// bent = vnf_bend(vnf, axis="Z");
// vnf_polyhedron(bent);
function vnf_bend(vnf,r,d,axis="Z") =
let(
chk_axis = assert(in_list(axis,["X","Y","Z"])),
@ -788,24 +795,18 @@ function vnf_bend(vnf,r,d,axis="Z") =
max(abs(bmax.y), abs(bmin.y)) :
max(abs(bmax.z), abs(bmin.z)),
r = get_radius(r=r,d=d,dflt=dflt),
width = axis=="X"? (bmax.y-bmin.y) : (bmax.x - bmin.x)
extent = axis=="X" ? [bmin.y, bmax.y] : [bmin.x, bmax.x]
)
assert(width <= 2*PI*r, "Shape would wrap more than completely around the cylinder.")
let(
span_chk = axis=="Z"?
assert(bmin.y > 0 || bmax.y < 0, "Entire shape MUST be completely in front of or behind y=0.") :
assert(bmin.z > 0 || bmax.z < 0, "Entire shape MUST be completely above or below z=0."),
min_ang = 180 * bmin.x / (PI * r),
max_ang = 180 * bmax.x / (PI * r),
ang_span = max_ang-min_ang,
steps = ceil(segs(r) * ang_span/360),
step = width / steps,
bend_at = axis=="X"? [for(i = [1:1:steps-1]) i*step+bmin.y] :
[for(i = [1:1:steps-1]) i*step+bmin.x],
steps = ceil(segs(r) * (extent[1]-extent[0])/(2*PI*r)),
step = (extent[1]-extent[0]) / steps,
bend_at = [for(i = [1:1:steps-1]) i*step+extent[0]],
facepolys = [for (face=vnf[1]) select(verts,face)],
splits = axis=="X"?
_split_polygons_at_each_y(facepolys, bend_at) :
_split_polygons_at_each_x(facepolys, bend_at),
slicedir = axis=="X"? "Y" : "X", // slice in y dir for X axis case, and x dir otherwise
splits = _slice_3dpolygons(facepolys, slicedir, bend_at),
newtris = _triangulate_planar_convex_polygons(splits),
bent_faces = [
for (tri = newtris) [
@ -822,7 +823,6 @@ function vnf_bend(vnf,r,d,axis="Z") =
) vnf_add_faces(faces=bent_faces);
function _split_polygon_at_x(poly, x) =
let(
xs = subindex(poly,0)
@ -838,8 +838,7 @@ function _split_polygon_at_x(poly, x) =
u = (x - p[0].x) / (p[1].x - p[0].x)
) [
x, // Important for later exact match tests
u*(p[1].y-p[0].y)+p[0].y,
u*(p[1].z-p[0].z)+p[0].z,
u*(p[1].y-p[0].y)+p[0].y
]
]
],
@ -853,88 +852,62 @@ function _split_polygon_at_x(poly, x) =
) out;
function _split_polygon_at_y(poly, y) =
let(
ys = subindex(poly,1)
) (min(ys) >= y || max(ys) <= y)? [poly] :
let(
poly2 = [
for (p = pair(poly,true)) each [
p[0],
if(
(p[0].y < y && p[1].y > y) ||
(p[1].y < y && p[0].y > y)
) let(
u = (y - p[0].y) / (p[1].y - p[0].y)
) [
u*(p[1].x-p[0].x)+p[0].x,
y, // Important for later exact match tests
u*(p[1].z-p[0].z)+p[0].z,
]
]
],
out1 = [for (p = poly2) if(p.y <= y) p],
out2 = [for (p = poly2) if(p.y >= y) p],
out3 = [
if (len(out1)>=3) each split_path_at_self_crossings(out1),
if (len(out2)>=3) each split_path_at_self_crossings(out2),
],
out = [for (p=out3) if (len(p) > 2) cleanup_path(p)]
) out;
/// Function: _split_polygons_at_each_x()
// Usage:
// splitpolys = split_polygons_at_each_x(polys, xs);
/// Topics: Geometry, Polygons, Intersections
// Description:
// Given a list of 3D polygons, splits all of them wherever they cross any X value given in `xs`.
// Arguments:
// polys = A list of 3D polygons to split.
// xs = A list of scalar X values to split at.
function _split_polygons_at_each_x(polys, xs, _i=0) =
assert( [for (poly=polys) if (!is_path(poly,3)) 1] == [], "Expects list of 3D paths.")
assert( is_vector(xs), "The split value list should contain only numbers." )
function _split_2dpolygons_at_each_x(polys, xs, _i=0) =
_i>=len(xs)? polys :
_split_polygons_at_each_x(
_split_2dpolygons_at_each_x(
[
for (poly = polys)
each _split_polygon_at_x(poly, xs[_i])
], xs, _i=_i+1
);
///Internal Function: _split_polygons_at_each_y()
// Usage:
// splitpolys = _split_polygons_at_each_y(polys, ys);
/// Function: _slice_3dpolygons()
/// Usage:
/// splitpolys = _slice_3dpolygons(polys, dir, cuts);
/// Topics: Geometry, Polygons, Intersections
// Description:
// Given a list of 3D polygons, splits all of them wherever they cross any Y value given in `ys`.
// Arguments:
// polys = A list of 3D polygons to split.
// ys = A list of scalar Y values to split at.
function _split_polygons_at_each_y(polys, ys, _i=0) =
/// Description:
/// Given a list of 3D polygons, a choice of X, Y, or Z, and a cut list, `cuts`, splits all of the polygons where they cross
/// X/Y/Z at any value given in cuts.
/// Arguments:
/// polys = A list of 3D polygons to split.
/// dir_ind = slice direction, 0=X, 1=Y, or 2=Z
/// cuts = A list of scalar values for locating the cuts
function _slice_3dpolygons(polys, dir, cuts) =
assert( [for (poly=polys) if (!is_path(poly,3)) 1] == [], "Expects list of 3D paths.")
assert( is_vector(ys), "The split value list should contain only numbers." )
_i>=len(ys)? polys :
_split_polygons_at_each_y(
[
for (poly = polys)
each _split_polygon_at_y(poly, ys[_i])
], ys, _i=_i+1
);
assert( is_vector(cuts), "The split list must be a vector.")
assert( in_list(dir, ["X", "Y", "Z"]))
let(
I = ident(3),
dir_ind = ord(dir)-ord("X")
)
flatten([for (poly = polys)
let(
plane = plane_from_polygon(poly),
normal = point3d(plane),
pnormal = normal - (normal*I[dir_ind])*I[dir_ind]
)
approx(pnormal,[0,0,0]) ? [poly] :
let (
pind = max_index(v_abs(pnormal)), // project along this direction
otherind = 3-pind-dir_ind, // keep dir_ind and this direction
keep = [I[dir_ind], I[otherind]], // dir ind becomes the x dir
poly2d = poly*transpose(keep), // project to 2d, putting selected direction in the X position
poly_list = [for(p=_split_2dpolygons_at_each_x([poly2d], cuts))
let(
a = p*keep, // unproject, but pind dimension data is missing
ofs = outer_product((repeat(plane[3], len(a))-a*normal)/plane[pind],I[pind])
)
a+ofs] // ofs computes the missing pind dimension data and adds it back in
)
poly_list
]);
// Section: Debugging VNFs
// Section: Debugging Polyhedrons
// Module: _show_vertices()
// Usage:
// _show_vertices(vertices, [size], [disabled=]);
// _show_vertices(vertices, [size])
// Description:
// Draws all the vertices in an array, at their 3D position, numbered by their
// position in the vertex array. Also draws any children of this module with
@ -942,8 +915,6 @@ function _split_polygons_at_each_y(polys, ys, _i=0) =
// Arguments:
// vertices = Array of point vertices.
// size = The size of the text used to label the vertices. Default: 1
// ---
// disabled = If true, don't draw numbers, and draw children without transparency. Default = false.
// Example:
// verts = [for (z=[-10,10], y=[-10,10], x=[-10,10]) [x,y,z]];
// faces = [[0,1,2], [1,3,2], [0,4,5], [0,5,1], [1,5,7], [1,7,3], [3,7,6], [3,6,2], [2,6,4], [2,4,0], [4,6,7], [4,7,5]];
@ -971,7 +942,7 @@ module _show_vertices(vertices, size=1) {
/// Module: _show_faces()
/// Usage:
/// _show_faces(vertices, faces, [size=], [disabled=]);
/// _show_faces(vertices, faces, [size=]);
/// Description:
/// Draws all the vertices at their 3D position, numbered in blue by their
/// position in the vertex array. Each face will have their face number drawn
@ -980,9 +951,7 @@ module _show_vertices(vertices, size=1) {
/// Arguments:
/// vertices = Array of point vertices.
/// faces = Array of faces by vertex numbers.
/// ---
/// size = The size of the text used to label the faces and vertices. Default: 1
/// disabled = If true, don't draw numbers, and draw children without transparency. Default: false.
/// Example(EdgesMed):
/// verts = [for (z=[-10,10], y=[-10,10], x=[-10,10]) [x,y,z]];
/// faces = [[0,1,2], [1,3,2], [0,4,5], [0,5,1], [1,5,7], [1,7,3], [3,7,6], [3,6,2], [2,6,4], [2,4,0], [4,6,7], [4,7,5]];
@ -1029,7 +998,7 @@ module _show_faces(vertices, faces, size=1) {
// Module: vnf_debug()
// Usage:
// vnf_debug(vnfs, [faces=], [vertices=], [convexity=], [txtsize=]);
// vnf_debug(vnfs, [faces], [vertices], [opacity], [size], [convexity]);
// Description:
// A drop-in module to replace `vnf_polyhedron()` to help debug vertices and faces.
// Draws all the vertices at their 3D position, numbered in blue by their
@ -1037,7 +1006,7 @@ module _show_faces(vertices, faces, size=1) {
// in red, aligned with the center of face. All given faces are drawn with
// transparency. All children of this module are drawn with transparency.
// Works best with Thrown-Together preview mode, to see reversed faces.
// You can set opacity to 0 if you want to disable the display of the polyhedron faces.
// You can set opacity to 0 if you want to supress the display of the polyhedron faces.
// .
// The vertex numbers are shown rotated to face you. As you rotate your polyhedron you
// can rerun the preview to display them oriented for viewing from a different viewpoint.
@ -1050,12 +1019,11 @@ module _show_faces(vertices, faces, size=1) {
// opacity = Opacity of the polyhedron faces. Default: 0.5
// convexity = The max number of walls a ray can pass through the given polygon paths.
// size = The size of the text used to label the faces and vertices. Default: 1
// disabled = If true, act exactly like `polyhedron()`. Default = false.
// Example(EdgesMed):
// verts = [for (z=[-10,10], a=[0:120:359.9]) [10*cos(a),10*sin(a),z]];
// faces = [[0,1,2], [5,4,3], [0,3,4], [0,4,1], [1,4,5], [1,5,2], [2,5,3], [2,3,0]];
// vnf_debug([verts,faces], txtsize=2);
module vnf_debug(vnf, convexity=6, size=1, faces=true, vertices=true, opacity=0.5) {
// vnf_debug([verts,faces], size=2);
module vnf_debug(vnf, faces=true, vertices=true, opacity=0.5, size=1, convexity=6 ) {
no_children($children);
if (faces)
_show_faces(vertices=vnf[0], faces=vnf[1], size=size);