From d8a444099f72cd8dec2e1b0bafee2a24b5658e1d Mon Sep 17 00:00:00 2001
From: Justin Lin <justin.sdk@gmail.com>
Date: Thu, 19 Aug 2021 16:36:42 +0800
Subject: [PATCH] add ivory_ball_fern_leaf

---
 examples/ivory_ball_fern_leaf.scad | 150 +++++++++++++++++++++++++++++
 1 file changed, 150 insertions(+)
 create mode 100644 examples/ivory_ball_fern_leaf.scad

diff --git a/examples/ivory_ball_fern_leaf.scad b/examples/ivory_ball_fern_leaf.scad
new file mode 100644
index 00000000..08b135d7
--- /dev/null
+++ b/examples/ivory_ball_fern_leaf.scad
@@ -0,0 +1,150 @@
+use <hull_polyline3d.scad>;
+use <hollow_out.scad>;
+use <util/dedup.scad>;
+use <turtle/lsystem2.scad>;
+use <experimental/ptf_c2sphere.scad>;
+
+$fn = 48;
+
+radius = 36;
+thickness = 2;
+spacing = 3;
+drill_angle = 38;
+support_thickness = 1;
+
+ivory_ball_fern_leaf(radius, thickness, spacing, drill_angle, support_thickness);
+
+module ivory_ball_fern_leaf(radius, thickness, spacing, drill_angle, support_thickness) {
+	module fern_ball(radius, thickness, fern_n, thickness_scale) {
+		function fern(n = 8, angle = 4, leng = 1, heading = 0, start = [0, 0]) = 
+			let(
+				axiom = "EEEA",
+				rules = [
+					["A", "[++++++++++++++EC]B+B[--------------ED]B+BA"],
+					["C", "[---------EE][+++++++++EE]B+C"],
+					["D", "[---------EE][+++++++++EE]B-D"]
+				]
+			)
+			lsystem2(axiom, rules, n, angle, leng, heading, start, forward_chars = "ABCDE");  
+			
+		r = radius * sin(drill_angle / 2) / 2;
+		fern = [
+			for(line = dedup(fern(n = fern_n)))
+			[
+				ptf_c2sphere(line[0] + [r, 0], radius * 0.99),
+				ptf_c2sphere(line[1] + [r, 0], radius * 0.99)
+			]
+		];
+
+		module ferns(n) {
+			a_step = 360 / n;
+			for(i = [0:n - 1]) {
+				rotate(i * a_step)
+				for(line = fern) {
+					hull_polyline3d(
+						line,
+						thickness * thickness_scale,
+						$fn = 5
+					);
+				}
+			}
+		}		
+
+		color("black") 
+		difference() {
+			sphere(radius);
+			sphere(radius - thickness);
+		}
+		
+		union() {
+			ferns(4);
+			
+			mirror([1, 0, 0])
+			mirror([0, 0, 1])
+				ferns(4);
+				
+			mirror([0, 1, 1])
+				ferns(2);
+
+			mirror([0, 1, 0])
+			mirror([0, 1, 1])
+				ferns(2);
+		}
+	}
+
+	r_step = thickness + spacing;
+	radiuses = [radius, radius - r_step, radius - r_step * 2];
+
+	fidget_ball_drill_support(radius, thickness, spacing, support_thickness) {
+	   fern_ball(radiuses[0], thickness, fern_n = 5, thickness_scale = 0.75);
+	   mirror([0, 1, 1]) fern_ball(radiuses[1], thickness, fern_n = 4, thickness_scale = 0.65);
+	   mirror([1, 1, 0]) fern_ball(radiuses[2], thickness, fern_n = 3, thickness_scale = 0.55);
+	};
+}
+
+module fidget_ball_drill_support(radius, thickness, spacing, support_thickness) {
+	module drill(deep, drill_angle) {
+		a = drill_angle / 2;
+		r = deep * tan(a);
+		
+		difference() {
+			children(0);
+			union() {
+				for(i = [0:3]) {
+					rotate([90 * i, 0, 0])
+					translate([0, 0, -deep])
+					linear_extrude(deep, scale = 0.01)
+						circle(r);
+				}
+				for(i = [90, -90]) {
+					rotate([0, i, 0])
+					translate([0, 0, -deep])
+					linear_extrude(deep, scale = 0.01)
+						circle(r);
+				}
+
+				for(i = [0:3]) {
+					rotate([0, 54.7356, 45 + i * 90])
+					translate([0, 0, -deep])
+					linear_extrude(deep, scale = 0.01)
+						circle(r);
+
+					rotate([0, -125.2644, 45 + i * 90])
+					translate([0, 0, -deep])
+					linear_extrude(deep, scale = 0.01)
+						circle(r);
+				}
+			}	
+		}
+	}
+
+	module support(i, sphere_r, height, support_thickness, drill_angle) {
+		a = drill_angle / 2;
+		support_r = 2 * sphere_r * sin(a / 2) ^ 2;
+
+		sina = sin(a);
+		tana = tan(a);
+
+		translate([0, 0, -sphere_r])
+		rotate_extrude()
+		translate([sphere_r * sina, 0])
+			polygon([[0, support_r], [-.75, support_r], [-tana * support_r - support_thickness, 0], [-tana * support_r, 0]]);
+
+		translate([0, 0, -sphere_r - height * i])
+		linear_extrude(height * i)
+		hollow_out(support_thickness)
+		    circle(sphere_r * sina - tana * support_r);
+
+	}
+
+	r_step = thickness + spacing;
+	
+	drill(radius, drill_angle)
+	for(i = [0:$children - 1]) {
+	    children(i);
+	}
+
+	for(i = [0:$children - 1]) {
+		support(i, radius - r_step * i, r_step, support_thickness, drill_angle);
+	}
+}