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add region centroid capability and consolidate into one centroid

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function for polygons, regions and VNFs.
Fix bug with anchors for linear_sweep (due to centerpoint issues)
Fix intersection anchors for vnfs when anchor vector intersects
in a path instead of a single point.
This commit is contained in:
Adrian Mariano
2021-10-20 22:44:55 -04:00
parent a7ca1b1b64
commit 76272d9d9a
10 changed files with 158 additions and 101 deletions
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29
vnf.scad
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@@ -457,12 +457,15 @@ function vnf_from_region(region, transform, reverse=false) =
// bool = is_vnf(x);
// Description:
// Returns true if the given value looks like a VNF structure.
function is_vnf(x) = is_list(x) && len(x)==2 && is_list(x[0]) && is_list(x[1])
&& is_vector(x[0][0],3) && is_vector(x[1][0]);
function is_vnf(x) =
is_list(x) &&
len(x)==2 &&
is_list(x[0]) &&
is_list(x[1]) &&
(x[0]==[] || (len(x[0])>=3 && is_vector(x[0][0]))) &&
(x[0]==[] || (len(x[0])>=3 && is_vector(x[0][0],3))) &&
(x[1]==[] || is_vector(x[1][0]));
@@ -684,7 +687,7 @@ function _slice_3dpolygons(polys, dir, cuts) =
// orient = Vector to rotate top towards, after spin. See [orient](attachments.scad#orient). Default: `UP`
module vnf_polyhedron(vnf, convexity=2, extent=true, cp=[0,0,0], anchor="origin", spin=0, orient=UP) {
vnf = is_vnf_list(vnf)? vnf_merge(vnf) : vnf;
cp = is_def(cp) ? cp : vnf_centroid(vnf);
cp = is_def(cp) ? cp : centroid(vnf);
attachable(anchor,spin,orient, vnf=vnf, extent=extent, cp=cp) {
polyhedron(vnf[0], vnf[1], convexity=convexity);
children();
@@ -760,17 +763,17 @@ function vnf_area(vnf) =
sum([for(face=vnf[1]) polygon_area(select(verts,face))]);
// Function: vnf_centroid()
// Usage:
// vol = vnf_centroid(vnf);
// Description:
// Returns the centroid of the given manifold VNF. The VNF must describe a valid polyhedron with consistent face direction and
// no holes; otherwise the results are undefined.
/// Function: _vnf_centroid()
/// Usage:
/// vol = _vnf_centroid(vnf);
/// Description:
/// Returns the centroid of the given manifold VNF. The VNF must describe a valid polyhedron with consistent face direction and
/// no holes; otherwise the results are undefined.
// Divide the solid up into tetrahedra with the origin as one vertex.
// The centroid of a tetrahedron is the average of its vertices.
// The centroid of the total is the volume weighted average.
function vnf_centroid(vnf) =
/// Divide the solid up into tetrahedra with the origin as one vertex.
/// The centroid of a tetrahedron is the average of its vertices.
/// The centroid of the total is the volume weighted average.
function _vnf_centroid(vnf,eps=EPSILON) =
assert(is_vnf(vnf) && len(vnf[0])!=0 )
let(
verts = vnf[0],
@@ -784,7 +787,7 @@ function vnf_centroid(vnf) =
[ vol, (v0+v1+v2)*vol ]
])
)
assert(!approx(pos[0],0, EPSILON), "The vnf has self-intersections.")
assert(!approx(pos[0],0, eps), "The vnf has self-intersections.")
pos[1]/pos[0]/4;