add walk_torus83_fort

examples/walk_torus83_fort.scad

@@ -0,0 +1,162 @@
+include <shape_starburst.scad>;
+include <hollow_out.scad>;
+
+// It works but some math is still required.
+
+thickness = 4;
+height = 20;
+radius = 75;
+
+// The idea is from Walk Torus83 Fort.
+// https://sketchfab.com/3d-models/walk-torus83-fort-44dc701f676d40f7aa1bee874db6fde9
+walk_torus83_fort(radius, thickness, height, $fn = 36);
+wall(radius, height, thickness, $fn = 36);
+
+module wall(radius, height, thickness) {
+    bk_number = 8;
+    half_thickness = thickness / 2;
+    ro = radius - half_thickness;
+    ri = ro * 0.541196;
+    leng = radius * 0.458804;
+    
+    bk_w = leng / bk_number / 2;   
+    module bk() {
+        for(i = [0:bk_number]) {
+            translate([(2 * i + 1) * bk_w, 0]) 
+                square(bk_w, center = true);
+        }
+    }    
+
+    module eight_pts_star(r, th) {    
+        hollow_out(shell_thickness = th) 
+            intersection() {
+                rotate(22.5) 
+                    polygon(shape_starburst(ro, ri, 8));
+                circle(r);
+            }
+    }
+
+    linear_extrude(height) 
+        eight_pts_star(ro - thickness, thickness);
+
+    translate([0, 0, height]) 
+        linear_extrude(half_thickness) 
+            difference() {
+                eight_pts_star(ro - thickness, thickness / 4);
+             
+                union() {
+                    for(i = [0:7]) {
+                        rotate(22.5 + i * 45) 
+                            translate([-ro, 0]) rotate(-22.5) {
+                                bk();
+                                rotate(45) bk();
+                            }
+                    }
+                }
+            }
+}
+
+module walk_torus83_fort(radius, thickness, height) {
+    stair_number = 13;
+    leng = radius * 0.458804;
+
+    module tower(leng, radius, height) {
+        linear_extrude(height) 
+            circle(radius);
+        translate([0, 0, height]) 
+            sphere(radius);
+    }
+
+    module stairs(height, n) {
+        w = height / n;
+        half_w = w / 2;
+                
+        for(i = [0:n - 1]) {
+            translate([w * i + w / 2, w * i + w / 2]) 
+                square(w, center = true);
+        }
+    }
+
+    module walkway(leng, thickness, height, wall_thickness, stair_number) {
+        half_leng = leng / 2;
+        half_h = height / 2;
+        r = thickness * 1.25;
+        door_w = thickness * 3.5;
+        p = [0, 0, -thickness * 2];
+        module door_df() {
+            circle(r);
+            translate([0, -thickness * 2]) 
+                square(door_w, center = true);
+        }
+
+        module half_door_df() {
+            door_w = thickness;
+            door_h = thickness * 3.5 - door_w;
+            half_dw = door_w / 2;
+            translate([-thickness * 1.75, -half_h]) {
+                square([door_w, door_h]);
+                translate([half_dw, door_h]) 
+                    circle(half_dw);
+            }
+        }
+        
+        tri_points = [[0, 0], [0, height], [-height, 0]];
+        leng2 = leng * 0.75;
+        half_leng2 = leng2 / 2;
+        
+        rotate([90, 0, 0]) 
+            linear_extrude(thickness, center = true) {
+                // walkway with doors
+                difference() {
+                    hull() {   
+                        translate([half_leng, 0, 0]) 
+                            square([leng, height], center = true);
+                        translate([-half_leng, -half_h])
+                            polygon(tri_points);
+                    }
+                    
+                    translate([-leng / 2.125, 0]) 
+                        door_df();
+                    
+                    half_door_df();
+                }
+                translate([-half_leng - height, -half_h]) 
+                    stairs(height, stair_number);
+                    
+                 // walkway without doors    
+                translate([-leng * 1.75, 0]) rotate([180, 0, 180]) {
+                    translate([half_leng2, 0]) 
+                        square([leng2, height], center = true);
+                    translate([0, -half_h]) 
+                        polygon(tri_points);
+                            
+                    translate([-leng * 0.625, -half_h + half_h / stair_number]) 
+                        square([leng / 2, height / stair_number], center = true);
+                    
+                    translate([-height, -half_h]) 
+                        stairs(height, stair_number);
+                }                    
+            }
+    }
+
+    module one_burst(leng, thickness, height, stair_number) {
+        half_thickness = thickness / 2;
+        offset = leng / 2 + half_thickness;
+
+        half_h = height / 2;
+
+        translate([leng, - thickness / 4]) 
+            tower(leng, thickness, height * 1.125); 
+            
+        road_width = thickness / 1.5;
+        translate([0, -half_thickness - road_width / 2, half_h - half_h / stair_number])
+            walkway(leng, road_width, height / stair_number * (stair_number - 1), thickness, stair_number);
+    }
+
+    offset = leng / 1.325;
+    for(i = [0:7]) {
+        rotate(45 * i) 
+           translate([offset, offset, 0]) 
+               one_burst(leng, thickness, height, stair_number);
+    }
+}