Doc tweak for modular hose. Add is_bool_list to common.scad. Add

line circle intersection and line bezier intersection.

beziers.scad

@@ -324,8 +324,6 @@ function bezier_segment_closest_point(curve, pt, max_err=0.01, u=0, end_u=1) =
     bezier_segment_closest_point(curve, pt, max_err=max_err, u=minima[0], end_u=minima[1]);
 
 
-
-
 // Function: bezier_segment_length()
 // Usage:
 //   pathlen = bezier_segment_length(curve, <start_u>, <end_u>, <max_deflect>);
@@ -361,6 +359,28 @@ function bezier_segment_length(curve, start_u=0, end_u=1, max_deflect=0.01) =
 
 
 
+// Function: bezier_line_intersection()
+// Usages: 
+//   u = bezier_line_intersection(curve, line);
+// Description:
+//   Finds the parameter(s) of the 2d curve whose Bezier control points are `curve`
+//   corresponding to its intersection points with the line through
+//   the pair of distinct 2d points in `line`. 
+// Arguments:
+//   curve = List of 2d control points for the Bezier curve
+//   line = a list of two distinct 2d points defining a line
+function bezier_line_intersection(curve, line) =
+    assert(is_path(curve,2), "The input ´curve´ must be a 2d bezier")
+    assert(_valid_line(line,2), "The input `line` is not a valid 2d line")
+    let( 
+        a = _bezier_matrix(len(curve)-1)*curve, // curve algebraic coeffs. 
+        n = [-line[1].y+line[0].y, line[1].x-line[0].x], // line normal
+        q = [for(i=[len(a)-1:-1:1]) a[i]*n, (a[0]-line[0])*n] // curve SDF to line
+    )
+    [for(u=real_roots(q)) if (u>=0 && u<=1) u];
+
+
+
 // Function: fillet3pts()
 // Usage:
 //   bez_path_pts = fillet3pts(p0, p1, p2, r);

common.scad

@@ -222,6 +222,18 @@ function _list_pattern(list) =
 function same_shape(a,b) = _list_pattern(a) == b*0;
 
 
+// Function: is_bool_list()
+// Usage:
+//   check = is_bool_list(list,<length>)
+// Description:
+//   Tests whether input is a list containing only booleans, and optionally checks its length.
+// Arguments:
+//   list = list to test
+//   length = if given, list must be this length
+function is_bool_list(list, length) =
+     is_list(list) && (is_undef(length) || len(list)==length) && []==[for(entry=list) if (!is_bool(entry)) 1];
+
+
 // Section: Handling `undef`s.
 
 

geometry.scad

@@ -1139,7 +1139,7 @@ function plane_line_angle(plane, line) =
 function plane_line_intersection(plane, line, bounded=false, eps=EPSILON) =
     assert( is_finite(eps) && eps>=0, "The tolerance should be a positive number." )
     assert(_valid_plane(plane,eps=eps) && _valid_line(line,dim=3,eps=eps), "Invalid plane and/or line.")
-    assert(is_bool(bounded) || (is_list(bounded) && len(bounded)==2), "Invalid bound condition(s).")
+    assert(is_bool(bounded) || is_bool_list(bounded,2), "Invalid bound condition.")
     let(
         bounded = is_list(bounded)? bounded : [bounded, bounded],
         res = _general_plane_line_intersection(plane, line, eps=eps)
@@ -1591,6 +1591,47 @@ function circle_circle_tangents(c1,r1,c2,r2,d1,d2) =
 
 
 
+// Function: circle_line_intersection()
+// Usage:
+//   isect = circle_line_intersection(c,r,line,<bounded>,<eps>);
+//   isect = circle_line_intersection(c,d,line,<bounded>,<eps>);
+// Description:
+//   Find intersection points between a 2d circle and a line, ray or segment specified by two points.
+//   By default the line is unbounded.
+// Arguments:
+//   c = center of circle
+//   r = radius of circle
+//   line = two points defining the unbounded line
+//   bounded = false for unbounded line, true for a segment, or a vector [false,true] or [true,false] to specify a ray with the first or second end unbounded.  Default: false
+//   eps = epsilon used for identifying the case with one solution.  Default: 1e-9
+//   --
+//   d = diameter of circle
+function circle_line_intersection(c,r,line,d,bounded=false,eps=EPSILON) =
+  let(r=get_radius(r=r,d=d,dflt=undef))
+  assert(_valid_line(line,2), "Input 'line' is not a valid 2d line.")
+  assert(is_vector(c,2), "Circle center must be a 2-vector")
+  assert(is_num(r) && r>0, "Radius must be positive")
+  assert(is_bool(bounded) || is_bool_list(bounded,2), "Invalid bound condition")
+  let(
+      bounded = force_list(bounded,2),
+      closest = line_closest_point(line,c),
+      d = norm(closest-c)
+  )
+  d > r ? [] :
+  let(
+     isect = approx(d,r,eps) ? [closest] :
+             let( offset = sqrt(r*r-d*d),
+                  uvec=unit(line[1]-line[0])
+             ) [closest-offset*uvec, closest+offset*uvec]
+
+  )
+  [for(p=isect)
+     if ((!bounded[0] || (p-line[0])*(line[1]-line[0])>=0)
+        && (!bounded[1] || (p-line[1])*(line[0]-line[1])>=0)) p];
+
+
+
+
 // Section: Pointlists
 
 

modular_hose.scad

@@ -126,7 +126,9 @@ _hose_waist = [1.7698, 1.8251, 3.95998];
 //    or you can make modular hose segments.  To make assembly possible with printed
 //    parts you can add clearances that make the ball end smaller and the socket end
 //    larger.  These work by simply increasing the radius of the whole end by the specified
-//    amount.  On a Prusa printer with PETG clearance values around .1 work, but you
+//    amount.  On a Prusa printer with PETG, a clearance of 0.05 allows the 3/4" hose parts to mate
+//    with standard modular hose or itself.  A clearance of 0.1 allows the 3/4" parts to mate with
+//    standard hoseclearance values around .1 work, but you
 //    will have to experiment with your machine and materials.  And note clearance values
 //    are different for the different sizes.
 // Arguments:
@@ -174,7 +176,7 @@ module modular_hose(size, type, clearance=0, waist_len, anchor=BOTTOM, spin=0,or
   center = mean(bounds);
   attachable(anchor,spin,orient,l=bounds[1].y-bounds[0].y, r=bounds[1].x)
   {
-    rotate_extrude()
+    rotate_extrude(convexity=4)
       polygon(fwd(center.y,p=shape));
     children();
   }