diff --git a/.github/workflows/makefile.yml b/.github/workflows/makefile.yml
index 3d1df1e..5acba30 100644
--- a/.github/workflows/makefile.yml
+++ b/.github/workflows/makefile.yml
@@ -16,7 +16,6 @@ jobs:
       run: sudo apt-get install -y openscad
     - uses: actions/checkout@v4
     - name: Cache STL Files
-      if: github.event_name != 'release'
       id: cache-stl
       uses: actions/cache@v4
       with:
@@ -25,16 +24,10 @@ jobs:
         restore-keys: |
           stlcache-${{ runner.os }}
     - name: read cache
-      if: github.event_name != 'release'
       run: .github/workflows/getcache
-    - name: fast build
-      if: github.event_name != 'release'
-      run: make -j $(nproc) EXTRA_FLAGS:=-D'\$$fn=16'
-    - name: detailed build
-      if: github.event_name == 'release'
+    - name: build
       run: make -j $(nproc)
     - name: create cache
-      if: github.event_name != 'release'
       run: .github/workflows/mkcache
     - name: Publish STL files
       uses: actions/upload-artifact@v4
diff --git a/README.md b/README.md
index 1a5a88e..d484b65 100644
--- a/README.md
+++ b/README.md
@@ -7,6 +7,9 @@ CAreadme.txt or the LDraw.org website. The code itself is rewritten
 from scratch but the same license nevertheless applies to this
 project as well.
 
+The models are also slightly modified for better printability on
+FDM printers.
+
 To build the code you may use the provided Makefile.
 
 If you modify or add new parts follow the style of the part module
diff --git a/soLDraw.scad b/soLDraw.scad
index 4feb6e0..a3a766f 100644
--- a/soLDraw.scad
+++ b/soLDraw.scad
@@ -1,12 +1,264 @@
 part = "3001"; // ["3001", "3002", "3003", "3004", "3005", "3006", "3007", "3008", "3009", "3010", "3011", "3020", "3021", "3022", "3023", "3024", "3026", "3027", "3028", "3029", "3030", "3031", "3032", "3033", "3034", "3035", "3036", "3037", "3038", "3039", "3040", "3041", "3042", "3043", "3044", "3045", "3046", "3048", "3049", "3058", "3068b", "3623", "3641", "3710", "3788", "3821", "3822", "3823", "3828", "3829a", "3937", "3938", "4070", "4079", "4213", "4214", "4215", "4315", "4600", "4624", "6141"]
 
-// minimum angle for a fragment
-$fa=1;
-// minimum size of a fragment
-$fs=0.2;
+$fn=32;
 
 sc=2/5;
 eps=1/128;
+unit=[1, 1, 1];
+bsp=1;
+
+module sc() render() scale(sc) children();
+
+module downext(h) mirror([0, 0, 1]) linear_extrude(h) children();
+module filt(s=[100, 100]) render() intersection() {
+    children();
+    linear_extrude(200, center=true)
+        translate(-eps*unit) square(s+eps*unit);
+}
+
+module cmirror() for(i=[0, 1]) mirror([i, -i, 0]) children();
+module dmirror() for(i=[0, 1]) mirror([i, i, 0]) children();
+module xmirror() for(i=[0, 1]) mirror([i, 0, 0]) children();
+module ymirror() for(i=[0, 1]) mirror([0, i, 0]) children();
+module fmirror() for(i=[0, 1], j=[0, 1])
+    mirror([i, 0, 0]) mirror([0, j, 0]) children();
+
+module acir(d, n=16) intersection_for(i=[360/n:360/n:90])
+    rotate(i) square(d, center=true);
+
+module bstud(stud=[true, true, false]) if(stud.x) filt() {
+    translate([0, 0, -eps]) linear_extrude(3.5) difference() {
+        acir(12);
+        if(stud.z) acir(8);
+    }
+    linear_extrude(4) difference() {
+        acir(11);
+        if(stud.z) acir(8);
+    }
+}
+
+module bstud3(h, stud=[true, true, false]) filt() {
+    translate([0, 10])
+        if(stud.y==2) {
+            downext(h) hull() for(i=[-2.5, 2.5])
+                translate([0, i]) acir(d=3);
+            downext(h-5) square([20, 2], center=true);
+        } else if(stud.y) downext(h) acir(8);
+}
+
+module bstud4(h, stud=[true, true, false]) if(stud.y) filt() {
+    translate([10, 10]) downext(h) difference() {
+        acir(20*sqrt(2)-12);
+        acir(12);
+    }
+    cmirror() downext(min(4, h))
+        translate([0, 9]) square(6, center=true);
+} else cmirror() downext(min(4, h))
+    translate([0, 9]) square([21, 6], center=true);
+
+
+module bcorner(h, stud=[true, true, false]) filt() {
+    bstud(stud);
+    downext(min(4-bsp, h)) square(20, center=true);
+    downext(h) cmirror()
+        translate([8, 0]) square([4, 20], center=true);
+}
+    
+module brcorner(h, stud=[true, true, false]) filt() {
+    bstud(stud);
+    downext(min(4-bsp, h)) acir(20, 32);
+    downext(h) difference() {
+        acir(20, 32);
+        acir(12, 32);
+     }
+}
+    
+module bicorner(h, stud=[true, true, false]) filt([10+eps, 10+eps]) {
+    bstud(stud);
+    downext(min(4-bsp, h)) square(20, center=true);
+    cmirror() {
+        downext(min(4, h))
+            translate([0, 9]) square([20, 6], center=true);
+        downext(h)
+            translate([8, 9]) square([4, 6], center=true);
+    }
+}
+    
+module bside(h, stud=[true, true, false]) filt([10, 10+eps]) {
+    bstud(stud);
+    downext(min(4-bsp, h)) square([20, 21], center=true);
+    downext(min(4, h)) translate([0, 9])
+        square([20, 6], center=true);
+    downext(h) translate([8, 0]) square([4, 21], center=true);
+}
+
+module bside3(h, stud=[true, true, false]) filt([10, 10+eps]) {
+    bside(h, stud);
+    bstud3(h, stud);
+}
+
+module binside(h, stud=[true, true, false])
+    filt([10+eps, 10+eps]) {
+        bstud(stud);
+        downext(min(4-bsp, h)) square([21, 21], center=true);
+        cmirror() downext(min(4, h))
+            translate([0, 9]) square([21, 6], center=true);
+    }
+
+module binside4(h, stud=[true, true, false])
+    filt([10+eps, 10+eps]) {
+        bstud(stud);
+        downext(min(4-bsp, h)) square([21, 21], center=true);
+        bstud4(h, stud);
+    }
+
+module ccorner(h, stud=[true, true, false]) render() {
+    bcorner(h, stud);
+    cmirror() rotate(90) bside(h, stud);
+    rotate(180) binside4(h, stud);
+}
+
+module cicorner(h, stud=[true, true, false]) render() {
+    rotate(180) bicorner(h, stud);
+    for(i=[0, 90, -90]) rotate(i) binside4(h, stud);
+}
+
+module cdcorner(h, stud=[true, true, false]) render() {
+    rotate(-90) brcorner(h, stud);
+    dmirror() bside3(h, stud);
+    rotate(90) {
+        bicorner(h, stud);
+        cmirror() bstud3(h);
+    }
+}
+
+module cside(h, stud=[true, true, false]) render() xmirror() {
+    rotate(90) bside(h, stud);
+    rotate(180) binside4(h, stud);
+}
+
+module csideicorner(h, stud=[true, true, false]) render() {
+    rotate(180) {
+        bicorner(h, stud);
+        mirror([1, -1, 0]) bstud3(h);
+    }
+    rotate(-90) binside4(h, stud);
+    rotate(90) bside3(h, stud);
+    rotate(90) mirror([0, 1, 0]) bside(h, stud);
+}
+
+module cdside(h, stud=[true, true, false]) render() fmirror()
+    rotate(90) bside3(h, stud);
+
+module cinside(h, stud=[true, true, false]) render() fmirror()
+    binside4(h, stud);
+
+module cterm(h, stud=[true, true, false]) render() ymirror() {
+    bcorner(h, stud);
+    rotate(90) bside3(h, stud);
+}
+
+module csingle(h, stud=[true, true, false]) render() fmirror()
+    bcorner(h, stud);
+
+module crsingle(h, stud=[true, true, false]) render() fmirror()
+    brcorner(h, stud);
+
+module dcore(s, stud=[true, true, false]) render()
+    let(h=s.z?24*s.z:8) fmirror() {
+        if(s.x==1 && s.y==1) {
+            csingle(h, stud);
+        } else if(s.x==1) {
+            translate([0, s.y-1]*10) rotate(90) cterm(h, stud);
+            for(i=[s.y-3:-2:0]) translate([0, i]*10)
+                rotate(90) cdside(h, stud);
+        } else if(s.y==1) {
+            translate([s.x-1, 0]*10) cterm(h, stud);
+            for(i=[s.x-3:-2:0])
+                translate([i, 0]*10) cdside(h, stud);
+        } else {
+            translate([s.x-1, s.y-1]*10) ccorner(h, stud);
+            for(i=[s.x-3:-2:0])
+                translate([i, s.y-1]*10) cside(h, stud);
+            for(i=[s.y-3:-2:0]) translate([s.x-1, i]*10)
+                rotate(-90) cside(h, stud);
+            for(i=[s.x-3:-2:0], j=[s.y-3:-2:0])
+                translate([i, j]*10) cinside(h, stud);
+        }
+    }
+
+module dbasic(s, stud=[true, true, false]) sc() dcore(s, stud);
+
+module dchamfer1(s, stud=[true, true, false]) sc()
+    translate([0, -10, 0]) difference() {
+        union() {
+            dcore(s, stud);
+            rotate([0, 90, 0])
+                linear_extrude(s.x*20, center=true)
+                    polygon([[0, 0], [0, 4],
+                        [20, -16], [20, -20]]);
+        }
+        rotate([45, 0, 0]) translate([-50, -100, 0]) cube(100);
+    }
+
+module dchamfer2(s, stud=[true, true, false]) sc()
+    translate([10, -10, 0]) difference() {
+        union() {
+            dcore(s, stud);
+            for(i=[0, 90])
+                rotate([0, 90, i])
+                    linear_extrude(s.x*20, center=true)
+                        polygon([[0, 0], [0, 4],
+                                 [20, -16], [20, -20]]);
+        }
+        for(i=[0, 90]) rotate([45, 0, i])
+            translate([-50, -100, 0]) cube(100);
+    }
+
+module dchamfer3(s, stud=[true, true, false]) sc() difference() {
+    union() {
+        dcore(s, stud);
+        for(i=[0, 180])
+            rotate([0, 90, i])
+                linear_extrude(s.x*20, center=true)
+                    polygon([[0, 0], [0, 4],
+                             [20, -16], [20, -20]]);
+    }
+    for(i=[0, 180]) rotate([45, 0, i])
+        translate([-50, -100, 0]) cube(100);
+}
+
+module dchamfer4(s, stud=[true, true, false]) sc()  difference() {
+    union() {
+        dcore(s, stud);
+        for(i=[0, 90, -90]) translate([0, i==0?10:0, 0])
+            rotate([0, 90, i])
+                linear_extrude((i?s.y:s.x)*20, center=true)
+                    polygon([[0, 0], [4, 0],
+                             [20, -16], [20, -20]]);
+    }
+    for(i=[0, 90, -90]) translate([0, i==0?10:0, 0])
+        rotate([45, 0, i]) translate([-50, -100, 0]) cube(100);
+}
+
+module dchamfer5(s, stud=[true, true, false], chamfer=5) sc()
+    translate([10, -10, 0]) difference() {
+        union() {
+            dcore(s, stud);
+            for(i=[0, 1]) mirror([i, i, 0]) intersection() {
+                rotate([0, 90, 0])
+                    linear_extrude(s.x*20, center=true)
+                        polygon([[0, 0], [0, 4],
+                                 [20, -16], [20, -20]]);
+                rotate([90, 90, 0])
+                    linear_extrude(s.x*20, center=true)
+                        polygon([[0, -4], [20, 16],
+                                 [20, 20], [0, 20]]);
+            }
+        }
+        intersection_for(i=[0, 90]) rotate([45, 0, i])
+            translate([-50, -100, 0]) cube(100);
+    }
 
 function v2(d) = [d, d];
 function v2d(s, d=0) = [s.x, s.y] * 20 - v2(d);
@@ -23,77 +275,12 @@ module stud(h, r1, r2=0, dir=1) mirror([0, 0, dir==-1?1:0])
         circle(d=r2);
     }
 
-module basic(s, stud=[true, true, false], cut=false,
-    chamfer=0) render() scale(sc)
-    translate([(chamfer==2||chamfer==5)?10:0,
-               (chamfer==1||chamfer==2||chamfer==5)?-10:0, 0])
-        difference() {
-            union() {
-                mirror([0, 0, 1]) difference() {
-                    union() {
-                        linear_extrude((s.z?24*s.z:8)-(cut?1:0))
-                            square(v2d(s), center=true);
-                        linear_extrude(s.z?24*s.z:8)
-                            square(v2d(s, 2), center=true);
-                    }
-                    translate([0, 0, 4])
-                        linear_extrude(s.z?24*s.z:8)
-                            square(v2d(s, 8), center=true);
-                }
-                if(stud.x) loc(s-v2(1)) stud(4, 12, stud.z?8:0);
-                if(stud.y)
-                    if(s.x>1 && s.y>1) loc(s-v2(2))
-                        stud(s.z?24*s.z:8, 16, 12, dir=-1);
-                    else loc(s-(s.x==1?[1, 2]:[2, 1]))
-                        stud(s.z?24*s.z:8, 8, dir=-1);
-                if(chamfer==5) for(i=[0, 1])
-                    mirror([i, i, 0]) intersection() {
-                        rotate([0, 90, 0])
-                            linear_extrude(s.x*20, center=true)
-                                polygon([[0, 0], [4, 0],
-                                        [20, -16], [20, -20]]);
-                        rotate([90, 90, 0])
-                            linear_extrude(s.x*20, center=true)
-                                polygon([[0, 0], [4, 0],
-                                         [20, 16], [20, 20],
-                                         [0, 20]]);
-                    }
-                if(chamfer==1||chamfer==2||
-                   chamfer==3||chamfer==4)
-                    translate([0, chamfer==4?10:0, 0])
-                    rotate([0, 90, 0])
-                        linear_extrude(s.x*20, center=true)
-                            polygon([[0, 0], [4, 0],
-                                     [20, -16], [20, -20]]);
-                if(chamfer==3)
-                    rotate([0, 90, 180])
-                        linear_extrude(s.x*20, center=true)
-                            polygon([[0, 0], [4, 0],
-                                     [20, -16], [20, -20]]);
-                if(chamfer==2||chamfer==4)
-                    rotate([0, 90, 90])
-                        linear_extrude(s.y*20, center=true)
-                            polygon([[0, 0], [4, 0],
-                                     [20, -16], [20, -20]]);
-                if(chamfer==4)
-                    rotate([0, 90, -90])
-                        linear_extrude(s.y*20, center=true)
-                            polygon([[0, 0], [4, 0],
-                                     [20, -16], [20, -20]]);
-            }
-            if(chamfer>=5) intersection_for(i=[0, 90])
-                rotate([45, 0, i])
-                    translate([-50, -100, 0]) cube(100);
-            else if(chamfer) for(i=chamfer==4?[0, 90, -90]:
-                                   chamfer==3?[0, 180]:
-                                   chamfer==2?[0, 90]:[0])
-                translate([0, (i==0&&chamfer==4)?10:0, 0])
-                rotate([45, 0, i])
-                    translate([-50, -100, 0]) cube(100);
-        }
+module stud0(cut=false) stud(4, 12, cut?8:0);
+module stud3(h) stud(h, 8, dir=-1);
+module stud4(h) stud(h, 20*sqrt(2)-12, 12, dir=-1);
 
 module large(s, stud=[true, true, true], cut=false)
-    render() scale(sc) {
+    sc() {
     mirror([0, 0, 1]) difference() {
         union() {
             linear_extrude((s.z?48*s.z:8)-(cut?1:0))
@@ -119,72 +306,54 @@ module large(s, stud=[true, true, true], cut=false)
             cube([8, 3, 47], center=true);
 }
 
-module p3001() /*[3001]*/ basic([4, 2, 1]);
-module p3002() /*[3002]*/ basic([3, 2, 1]);
-module p3003() /*[3003]*/ basic([2, 2, 1]);
-module p3004() /*[3004]*/ basic([2, 1, 1]);
-module p3005() /*[3005]*/ basic([1, 1, 1]);
-module p3006() /*[3006]*/ basic([10, 2, 1]);
+module p3001() /*[3001]*/ dbasic([4, 2, 1]);
+module p3002() /*[3002]*/ dbasic([3, 2, 1]);
+module p3003() /*[3003]*/ dbasic([2, 2, 1]);
+module p3004() /*[3004]*/ dbasic([2, 1, 1]);
+module p3005() /*[3005]*/ dbasic([1, 1, 1]);
+module p3006() /*[3006]*/ dbasic([10, 2, 1]);
 
-module p3007() /*[3007]*/ render() {
-    basic([8, 2, 1]);
-    scale(sc) mirror([0, 0, 1]) linear_extrude(18.5)
+module p3007() /*[3007]*/ sc() {
+    dcore([8, 2, 1]);
+    mirror([0, 0, 1]) linear_extrude(18.5)
         for(i=[-40,0,40], j=[-12, 12]) translate([i, j])
             square([2, 10], center=true);
 }
 
-module p3008() /*[3008]*/ basic([8, 1, 1]);
-module p3009() /*[3009]*/ basic([6, 1, 1]);
-module p3010() /*[3010]*/ basic([4, 1, 1]);
+module p3008() /*[3008]*/ dbasic([8, 1, 1]);
+module p3009() /*[3009]*/ dbasic([6, 1, 1]);
+module p3010() /*[3010]*/ dbasic([4, 1, 1]);
 module p3011() /*[3011]*/ large([4, 2, 1]);
-module p3020() /*[3020]*/ basic([4, 2, 0]);
-module p3021() /*[3021]*/ basic([3, 2, 0]);
-module p3022() /*[3022]*/ basic([2, 2, 0]);
-module p3023() /*[3023]*/ basic([2, 1, 0]);
-module p3024() /*[3024]*/ basic([1, 1, 0]);
-module p3026() /*[3026]*/ basic([24, 6, 0]);
-module p3027() /*[3027]*/ basic([16, 6, 0]);
-module p3028() /*[3028]*/ basic([12, 6, 0]);
-module p3029() /*[3029]*/ basic([12, 4, 0]);
-module p3030() /*[3030]*/ basic([10, 4, 0]);
-module p3031() /*[3031]*/ basic([4, 4, 0]);
-module p3032() /*[3032]*/ basic([6, 4, 0]);
-module p3033() /*[3033]*/ basic([10, 6, 0]);
-module p3034() /*[3034]*/ basic([8, 2, 0]);
-module p3035() /*[3035]*/ basic([8, 4, 0]);
-module p3036() /*[3036]*/ basic([8, 6, 0]);
-module p3037() /*[3037]*/ basic([4, 2, 1], chamfer=1);
-module p3038() /*[3038]*/ basic([3, 2, 1], chamfer=1);
-module p3039() /*[3039]*/ basic([2, 2, 1], chamfer=1);
-module p3040() /*[3040]*/ basic([1, 2, 1], chamfer=1);
-module p3041() /*[3041]*/ basic([4, 2, 1], chamfer=3);
-module p3042() /*[3042]*/ basic([3, 2, 1], chamfer=3);
-module p3043() /*[3043]*/ basic([2, 2, 1], chamfer=3);
-module p3044() /*[3044]*/ render() {
-    basic([1, 2, 1], stud=[false, false], chamfer=3);
-    scale(sc) mirror([0, 0, 1]) translate([0, 0, 4]) {
-        linear_extrude(20) hull() for(i=[-2.5, 2.5])
-            translate([0, i]) circle(d=3);
-        linear_extrude(15) square([20, 2], center=true);
-    }
-}
-module p3045() /*[3045]*/ basic([2, 2, 1], chamfer=2);
-module p3046() /*[3046]*/ basic([2, 2, 1], chamfer=5);
-module p3048() /*[3048]*/ render() {
-    basic([2, 1, 1], stud=[false, false], chamfer=4);
-    scale(sc) difference() {
-        mirror([0, 0, 1]) translate([0, 0, 4]) {
-            linear_extrude(20) hull() for(i=[-2.5, 2.5])
-                translate([i, 0]) circle(d=3);
-            linear_extrude(15) square([2, 20], center=true);
-        }
-        translate([0, 10, 0]) rotate([45, 0, 0])
-            translate([-50, -100, 0]) cube(100);
-    }
-}
+module p3020() /*[3020]*/ dbasic([4, 2, 0]);
+module p3021() /*[3021]*/ dbasic([3, 2, 0]);
+module p3022() /*[3022]*/ dbasic([2, 2, 0]);
+module p3023() /*[3023]*/ dbasic([2, 1, 0]);
+module p3024() /*[3024]*/ dbasic([1, 1, 0]);
+module p3026() /*[3026]*/ dbasic([24, 6, 0]);
+module p3027() /*[3027]*/ dbasic([16, 6, 0]);
+module p3028() /*[3028]*/ dbasic([12, 6, 0]);
+module p3029() /*[3029]*/ dbasic([12, 4, 0]);
+module p3030() /*[3030]*/ dbasic([10, 4, 0]);
+module p3031() /*[3031]*/ dbasic([4, 4, 0]);
+module p3032() /*[3032]*/ dbasic([6, 4, 0]);
+module p3033() /*[3033]*/ dbasic([10, 6, 0]);
+module p3034() /*[3034]*/ dbasic([8, 2, 0]);
+module p3035() /*[3035]*/ dbasic([8, 4, 0]);
+module p3036() /*[3036]*/ dbasic([8, 6, 0]);
+module p3037() /*[3037]*/ dchamfer1([4, 2, 1]);
+module p3038() /*[3038]*/ dchamfer1([3, 2, 1]);
+module p3039() /*[3039]*/ dchamfer1([2, 2, 1]);
+module p3040() /*[3040]*/ dchamfer1([1, 2, 1]);
+module p3041() /*[3041]*/ dchamfer3([4, 2, 1]);
+module p3042() /*[3042]*/ dchamfer3([3, 2, 1]);
+module p3043() /*[3043]*/ dchamfer3([2, 2, 1]);
+module p3044() /*[3044]*/ dchamfer3([1, 2, 1], stud=[false, 2]);
+module p3045() /*[3045]*/ dchamfer2([2, 2, 1]);
+module p3046() /*[3046]*/ dchamfer5([2, 2, 1]);
+module p3048() /*[3048]*/ dchamfer4([2, 1, 1], stud=[false, 2]);
 module p3049() /*[3049]*/ render() {
-    rotate(90) basic([1, 2, 1], chamfer=3);
-    scale(sc) intersection() {
+    rotate(90) dchamfer3([1, 2, 1]);
+    sc() intersection() {
         rotate([0, 90, 0]) linear_extrude(40, center=true)
             polygon([[0, 10], [0, 30], [20, 10]]);
         rotate([90, 90, 0]) linear_extrude(60, center=true)
@@ -193,85 +362,66 @@ module p3049() /*[3049]*/ render() {
     }
 }
 
-module p3058() /*[3058]*/ render() scale(sc) {
-    mirror([0, 0, 1]) linear_extrude(4) difference() {
-        square([320, 120], center=true);
-        square([200, 40], center=true);
-        square([160, 80], center=true);
+module p3058() /*[3058]*/ sc() fmirror() {
+    for(i=[7:-2:1]) translate([i, 5]*10) cdside(8);
+    translate([15, 5]*10) ccorner(8);
+    translate([9, 3]*10) rotate(180) ccorner(8);
+    for(i=[13, 11]) translate([i, 5]*10) cside(8);
+    for(i=[3, 1]) {
+        translate([15, i]*10) rotate(-90) cside(8);
+        translate([13, i]*10) cinside(8);
     }
-    mirror([0, 0, 1]) linear_extrude(8) {
-        difference() {
-            square([320, 120], center=true);
-            square([312, 112], center=true);
-        }
-        difference() {
-            union() {
-                square([208, 48], center=true);
-                square([168, 88], center=true);
-            }
-            square([200, 40], center=true);
-            square([160, 80], center=true);
-        }
-    }
-    for(i=[0, 1], j=[0, 1]) mirror([i, 0, 0]) mirror([0, j, 0]) {
-        translate([80, 50, 0]) loc([7, 0]) stud(4, 12);
-        translate([120, 30, 0]) loc([3, 0]) stud(4, 12);
-        translate([130, 10, 0]) loc([2, 0]) stud(4, 12);
-        translate([0, 50, 0]) loc([8, 0]) stud(8, 8, dir=-1);
-        translate([120, 40, 0]) loc([2, 0])
-            stud(8, 16, 12, dir=-1);
-        translate([130, 0, 0]) loc([1, 2])
-            stud(8, 16, 12, dir=-1);
+    translate([11, 1]*10) rotate(90) cside(8);
+    translate([11, 3]*10) cicorner(8);
+    translate([9, 5]*10) csideicorner(8);
+}
+
+module p3068b() /*[3068b]*/ sc() difference() {
+    dcore([2, 2, 0], stud=[false, true]);
+    translate([0, 0, -7]) downext(10) difference() {
+        square(41, center=true);
+        square(38, center=true);
     }
 }
-module p3068b() /*[3068b]*/
-    basic([2, 2, 0], stud=[false, true], cut=true);
-module p3623() /*[3623]*/ basic([3, 1, 0]);
+module p3623() /*[3623]*/ dbasic([3, 1, 0]);
 
 // wheel
-module p3641() /*[3641]*/ render() {
+module p3641() /*[3641]*/ sc() {
     for(i=[0:45/2:360], j=[0, 1])
         rotate([90-j*180, i-j*eps, 0])
-            rotate_extrude(angle=45/4+eps) scale(sc) polygon([
+            rotate_extrude(angle=45/4+eps, $fn=32) polygon([
                 [14, 0], [14, 8], [10, 8], [10, 4], [8, 3],
                 [8, -3], [10, -4], [10, -8], [18, -8], [18, 0]]);
 }
 
-module p3710() /*[3710]*/ basic([4, 1, 0]);
+module p3710() /*[3710]*/ dbasic([4, 1, 0]);
 
-module p3788() /*[3788]*/ render() {
-    translate([0, 0, -8*sc]) basic([2, 2, 0]);
+module p3788() /*[3788]*/ sc() {
+    translate([0, 0, -8]) dcore([2, 2, 0]);
     for(i=[0, 1]) mirror([i, 0, 0])
-    translate([30*sc, 0, 0]) difference() {
-        basic([1, 2, 2/3], stud=[true, false]);
-        scale(sc) rotate([0, 90, 0]) linear_extrude(20)
+    translate([30, 0, 0]) difference() {
+        dcore([1, 2, 2/3], stud=[true, false]);
+        rotate([0, 90, 0]) linear_extrude(20)
         polygon([[17, 16], [16, 16], [5, 8],
                  [5, -8], [16, -16], [17, -16]]);
-        scale(sc) rotate([90, 180, 0]) linear_extrude(32, center=true)
+        rotate([90, 180, 0]) linear_extrude(32, center=true)
         polygon([[0, 17], [10, 17], [10, 16], [6, 6]]);
     }
 }
 
-module p3821() /*[3821]*/ render() scale(sc) {
-    stud(4, 12);
-    stud(4, 20, dir=-1);
+module p3821() /*[3821]*/ sc() {
+    crsingle(24);
+    rotate(90) bcorner(24);
     difference() {
         union() {
-            mirror([0, 0, 1]) linear_extrude(24) difference() {
-                union() {
-                    circle(d=20);
-                    rotate(90) square(10);
-                    translate([-10, 0, 0]) square([4, 50]);
-                }
-                circle(d=12);
-            }
+            downext(24) translate([-10, 0, 0]) square([4, 50]);
             rotate([0, -90, 0]) translate([0, 0, 7])
                 linear_extrude(8) hull() for(i=[36, 44])
-                    translate([-12, i]) circle(d=4);
+                    translate([-12, i]) acir(4);
         }
         rotate([0, -90, 0]) {
             translate([0, 0, 5]) linear_extrude(8)
-                translate([-12, 44]) circle(d=4);
+                translate([-12, 44]) acir(4);
             translate([0, 0, 10]) linear_extrude(3)
                 translate([-12, 49]) square(10, center=true);
         }
@@ -280,31 +430,18 @@ module p3821() /*[3821]*/ render() scale(sc) {
 
 module p3822() /*[3822]*/ render() mirror([1, 0, 0]) p3821();
 
-module p3823() /*[3823]*/ render() scale(sc) {
-    for(i=[-30, 30]) translate([i, 0]) stud(4, 12, 8);
-    translate([0, -20, -40]) loc([2, 0]) stud(8, 8, dir=-1);
-    for(i=[-30, 30]) translate([i, -10, -40]) stud(8, 8, dir=-1);
-    translate([0, 0, -48]) difference() {
-        linear_extrude(8) difference() {
-            hull() {
-                for(i=[-30, 30]) translate([i, -20])
-                    circle(d=20);
-                square([80, 20], center=true);
-            }
-            for(i=[-20, 20]) translate([i, 10]) circle(d=20);
-            square([40, 20], center=true);
-        }
-        linear_extrude(4) {
-            difference() {
-                hull() {
-                    for(i=[-30, 30]) translate([i, -20])
-                        circle(d=12);
-                    square([72, 12], center=true);
-                }
-                square([48, 28], center=true);
-            }
-            for(i=[-20, 20]) translate([i, 10])
+module p3823() /*[3823]*/ sc() xmirror() {
+    translate([30, 0]) fmirror() bstud([true, true, true]);
+    translate([0, 0, -40]) {
+        translate([10, -20]) cdside(8, [false, true]);
+        translate([30, -20]) cdcorner(8, [false, true]);
+        translate([30, 0]) {
+            bcorner(8, [false, true]);
+            xmirror() rotate(180) bside3(8, [false, true]);
+            downext(4-bsp) difference() {
                 square(20, center=true);
+                translate([-10, 10]) acir(20, 32);
+            }
         }
     }
     multmatrix([[1, 0, 0, 0],
@@ -312,33 +449,32 @@ module p3823() /*[3823]*/ render() scale(sc) {
                 [0, 0, 1, 0]]) mirror([0, 0, 1])
         linear_extrude(40) difference() {
             hull() {
-                for(i=[-30, 30]) translate([i, 0])
-                    circle(d=20);
-                translate([0, 5]) square([80, 10], center=true);
+                translate([30, 0]) acir(20, 32);
+                square([40, 10]);
+                square([1, 20], center=true);
             }
             hull() {
-                for(i=[-30, 30]) translate([i, 0])
-                    circle(d=12);
-                translate([0, 5]) square([72, 10], center=true);
+                translate([30, 0]) acir(12, 32);
+                square([36, 10]);
+                translate([0, 4]) square([1, 20], center=true);
             }
         }
-    for(i=[-38, 38], j=[0, 10]) translate([i, 5-j, -20-j])
-        cube([4, 10, 40-2*j], center=true);
-    mirror([0, 0, 1]) linear_extrude(4) for(i=[0, 1])
-        mirror([i, 0]) translate([30, 0]) {
-            circle(d=20);
-            for(i=[0, 180]) rotate(i) square(10);
-        }
+    for(i=[0, 10]) translate([38, 5-i, -20-i])
+        cube([4, 10, 40-2*i], center=true);
+    downext(4) translate([30, 0]) {
+        circle(d=20);
+        dmirror() square(10);
+    }
 }
 
-module p3828() /*[3828]*/ render() scale(sc) {
+module p3828() /*[3828]*/ sc() {
     linear_extrude(4, center=true) difference() {
-        circle(d=28);
-        circle(d=24);
+        acir(28, 32);
+        acir(24, 32);
     }
     mirror([0, 0, 1]) linear_extrude(6) difference() {
-        circle(d=12);
-        circle(d=8);
+        acir(12, 32);
+        acir(8, 32);
     }
     for(i=[0, 120, 240]) rotate([90, 180, i])
         linear_extrude(3, center=true)
@@ -346,65 +482,66 @@ module p3828() /*[3828]*/ render() scale(sc) {
                      [12, 2], [6, 6], [4, 6]]);
 }
 
-module p3829a() /*[3829a]*/ render() {
-    basic([2, 1, 0], stud=[false, true]);
-    scale(sc) {
-        translate([0, -6, 0]) difference() {
-            linear_extrude(24) {
-                translate([-10, -4]) square([20, 4]);
-                difference() {
-                    scale([1, 3/4]) circle(d=12);
-                    translate([-10, -8]) square([20, 4]);
-                }
+module p3829a() /*[3829a]*/ sc() {
+    dcore([2, 1, 0], stud=[false, true]);
+    translate([0, -6, 0]) difference() {
+        linear_extrude(24) {
+            translate([-10, -4]) square([20, 4]);
+            difference() {
+                scale([1, 3/4]) acir(12, 32);
+                translate([-10, -8]) square([20, 4]);
             }
-            translate([0, 0, 24]) rotate([-53.13, 0, 0])
-                translate([0, 0, 10]) cube(20, center=true);
         }
-        translate([0, -10, 24]) rotate([-53.13, 0, 0]) translate([0, 4, 0]) cylinder(9, d=8);
+        translate([0, 0, 24]) rotate([-53.13, 0, 0])
+            translate([0, 0, 10]) cube(20, center=true);
     }
+    translate([0, -10, 24]) rotate([-53.13, 0, 0])
+        translate([0, 4, 0]) linear_extrude(9) acir(8, 32);
 }
 
-module p3937() /*[3937]*/ render() scale(sc)
-    for(i=[0, 1]) mirror([i, 0, 0]) {
+module p3937() /*[3937]*/ sc() xmirror() {
     translate([0, 7, -24]) cube([20, 3, 22]);
-    translate([0, -8, -20]) cube([20, 18, 4]);
+    translate([0, -8, -16]) {
+        downext(4-bsp) square([20, 18]);
+        downext(4) difference() {
+            square([20, 18]);
+            translate([4, 2]) square([12, 12]);
+        }
+    }
     translate([0, -10, -24]) linear_extrude(4) difference() {
         square([20, 20]);
         polygon([[2, 4], [16, 4], [16, 16], [2, 16],
                  [2, 12], [4, 12], [4, 8], [2, 8]]);
     }
-    rotate([0, 90, 0]) linear_extrude(2) hull()
-        for(i=[10, 16]) translate([i, 0]) circle(d=4);
-    rotate([0, 90, 0]) translate([0, 0, 16]) linear_extrude(4) translate([10, 0]) difference() {
-        hull() {
-            circle(d=16);
-            translate([-8, 0]) square([16, 10]);
-            translate([0, -8]) square(8);
-        }
-        circle(d=8);
-        polygon([
-            [0, 2.5],
-            [-10, 5],
-            [-10, -5],
-            [0, -2.5],
-        ]);
- difference() {
-    translate([-8, -4])
-        circle(d=6);
-    translate([-4.92, -4.85])
-        circle(d=2.2);
-        }
+    rotate([0, 90, 0]) {
+        linear_extrude(2) hull()
+            for(i=[10, 16]) translate([i, 0]) acir(4, 32);
+        translate([0, 0, 16]) linear_extrude(4)
+            translate([10, 0]) difference() {
+                hull() {
+                    acir(16, 32);
+                    translate([-8, 0]) square([16, 10]);
+                    translate([0, -8]) square(8);
+                }
+                acir(8, 32);
+                polygon([[0, 2.5], [-10, 5],
+                         [-10, -5], [0, -2.5]]);
+                difference() {
+                    translate([-8, -4]) acir(6, 32);
+                    translate([-4.92, -4.85]) acir(2.2, 32);
+                }
+            }
     }
 }
 
-module p3938() /*[3938]*/ render() {
-    basic([2, 1, 1/12], stud=[true, false, true]);
-    scale(sc) rotate([0, 90, 0]) translate([10, 0]) {
+module p3938() /*[3938]*/ sc() {
+    dcore([2, 1, 1/12], stud=[true, false, true]);
+    rotate([0, 90, 0]) translate([10, 0]) {
         difference() {
             union() {
-                cylinder(40, d=8, center=true);
+                linear_extrude(40, center=true) acir(8, 32);
                 linear_extrude(32, center=true) {
-                    circle(d=12);
+                    acir(12, 32);
                     translate([-5, 0])
                         square([10, 12], center=true);
                 }
@@ -416,81 +553,79 @@ module p3938() /*[3938]*/ render() {
     }
 }
 
-// ample +double line
-module p4070() /*[4070]*/ render() scale(sc) difference() {
+// ample
+module p4070() /*[4070]*/ sc() difference() {
     union() {
-        cylinder(4, d=12);
+        fmirror() bstud();
         translate([0, -6, -10]) rotate([90, 0, 0])
-            cylinder(4, d=12);
+            fmirror() bstud();
         translate([-10, -6, -24]) cube([20, 16, 24]);
         translate([-10, -10, -24]) cube([20, 20, 4]);
-        translate([0, -6, -20]) rotate([45, 0, 0])
-            cube([20, eps, eps], center=true);
     }
-    translate([-6, -6, -24]) cube([12, 12, 4]);
+    translate([-6, -6, -24]) cube([12, 12, 4+bsp]);
+    translate([-6, -10, -20]) cube([12, 16, bsp]);
     translate([-6, -2, -24]) cube([12, 8, 20]);
     translate([-6, -2, -16]) cube([12, 13, 12]);
-    translate([0, 0, -10]) rotate([90, 0, 0]) cylinder(11, d=8);
+    translate([0, 0, -10]) rotate([90, 0, 0])
+        linear_extrude(11) acir(8);
 }
 
-module p4079() /*[4079]*/ render() scale(sc) {
-    translate([0, -10]) loc([1, 0]) stud(4, 12);
-    stud(8, 16, 12, dir=-1);
+module p4079() /*[4079]*/ sc() {
+    intersection() {
+        dcore([2, 2, 0], stud=[false, true]);
+        downext(8) hull() for(i=[-16, 16]) {
+            translate([i, -16]) acir(8, 32);
+            translate([i, 16]) square(8, center=true);
+        }
+    }
+    translate([0, -10]) loc([1, 0]) fmirror() bstud();
     difference() {
-        union() {
-            mirror([0, 0, -1]) linear_extrude(8) hull() {
-                for(i=[-16, 16]) translate([i, -16]) circle(d=8);
-                for(i=[-16, 16]) translate([i, 16])
-                    square(8, center=true);
+        translate([0, 0, 40])
+        multmatrix([[1, 0, 0, 0],
+                    [0, 1, 1/16, 0],
+                    [0, 0, 1, 0]])
+        translate([0, 0, -40]) translate([0, 20, 0]) {
+            rotate([-90, 0, 0]) linear_extrude(5) hull() {
+                for(i=[-16, 16]) translate([i, -36]) acir(8, 32);
+                translate([0, -16])
+                    square([40, 16], center=true);
             }
-            translate([0, 0, 40])
-            multmatrix([[1, 0, 0, 0],
-                        [0, 1, 1/16, 0],
-                        [0, 0, 1, 0]])
-            translate([0, 0, -40]) translate([0, 20, 0]) {
-                rotate([-90, 0, 0]) linear_extrude(5) hull() {
-                    for(i=[-16, 16]) translate([i, -36])
-                        circle(d=8);
-                    translate([0, -16])
-                        square([40, 16], center=true);
+            translate([0, -8, 8]) rotate([0, 90, 0])
+                linear_extrude(40, center=true) intersection() {
+                    acir(26, 32);
+                    difference() {
+                        square([9, 13]);
+                        acir(16, 32);
+                    }
                 }
-                translate([0, -8, 8]) rotate([0, 90, 0])
-                    linear_extrude(40, center=true)
-                        intersection() {
-                            circle(d=26);
-                            difference() {
-                                square(13);
-                                circle(d=16);
-                            }
-                        }
-            }
         }
         rotate([0, 90, 0]) linear_extrude(28, center=true)
             hull() for(i=[-40, -7], j=[0, 13])
-                translate([i, j]) circle(d=14);
-        mirror([0, 0, -1]) translate([0, 0, 8])
-           cube([32, 32, 8], center=true);
+                translate([i, j]) acir(14, 32);
     }
 }
 
-module p4213() /*[4213]*/ render() scale(sc) {
-    translate([0, -10]) loc([3, 2]) stud(4, 12);
+module p4213() /*[4213]*/ sc() {
+    translate([0, -10]) loc([3, 2]) fmirror() bstud();
     translate([0, -20]) difference() {
-        loc([2, 0]) stud(8, 16, 12, dir=-1);
+        loc([2, 0]) downext(8) difference() {
+            acir(20*sqrt(2)-12);
+            acir(12);
+        }
         mirror([0, 0, 1])
-            for(i=[-22.5, 45, 112.5]) rotate(i) cube(8);
+            for(i=[-22.5, 45, 112.5]) rotate(i) cube(9);
     }
     difference() {
         rotate([0, 90, 0]) linear_extrude(80, center=true)
             hull() {
-                translate([4, 36]) circle(d=8);
+                translate([4, 36]) acir(8, 32);
                 translate([0, -40]) square(8);
             }
         for(i=[-38, -20, 0, 20, 38]) translate([i, 40, 0])
             cube([4, 16, 20], center=true);
         for(i=[-43.25, 43.25]) translate([i, 36, -4])
             intersection() {
-                sphere(d=16);
+                sphere(d=16, $fn=32);
                 cube([16, 8, 8], center=true);
             }
         mirror([0, 0, 1]) translate([0, 0, 3])
@@ -516,87 +651,83 @@ module hinge() {
         for(j=[-38, -20, 0, 20, 38]) translate([j, 0, 0])
             rotate([0, -90, 0]) linear_extrude(4, center=true)
                 hull() for(i=[0, 4]) translate([i, 0])
-                    circle(d=8);
+                    acir(8, 32);
         for(i=[0, 1]) mirror([i, 0, 0])
             translate([43.25, 0, 4]) intersection() {
-                sphere(d=16);
+                sphere(d=16, $fn=32);
                 translate([-11.25, 0, 0]) cube(8, center=true);
             }
 }
 
-module p4214() /*[4214]*/ render() {
-    for(i=[-30, 30]) translate([i, 0, -40]*sc)
-        basic([1, 1, 0], [false, false, false]);
-    scale(sc) {
-        translate([-20, 10, -40])
-            mirror([0, 0, 1]) mirror([0, 1, 0]) {
-                cube([40, 4, 8]);
-                cube([40, 10, 2]);
-            }
-        mirror([0, 0, 1]) linear_extrude(4) difference() {
-            square([80, 20], center=true);
-            hull() for(i=[-30, 30], j=[-4, -10])
-                translate([i, j]) circle(d=12);
-        }
-        mirror([0, 0, 1]) linear_extrude(48) for(i=[-38, 38])
-            translate([i, 0]) square([4, 20], center=true);
-        translate([0, 6, 0]) hinge();
+module p4214() /*[4214]*/ sc() {
+    for(i=[-30, 30]) translate([i, 0, -40])
+        dcore([1, 1, 0], [false, false, false]);
+    translate([-20, 6, -48]) cube([40, 4, 8]);
+    translate([-20, 0, -42]) cube([40, 10, 2]);
+    downext(4) difference() {
+        square([80, 20], center=true);
+        hull() for(i=[-30, 30], j=[-4, -10])
+            translate([i, j]) acir(12, 32);
     }
+    downext(48) for(i=[-38, 38])
+        translate([i, 0]) square([4, 20], center=true);
+    translate([0, 6, 0]) hinge();
 }
 
-module p4215() /*[4215]*/ render() {
-    basic([4, 1, 1/6], [true, false, true]);
-    translate([0, 0, -64]*sc)
-        basic([4, 1, 0], [false, true, false]);
-    scale(sc) translate([-40, 10, 0])
-        mirror([0, 0, 1]) mirror([0, 1, 0]) cube([80, 4, 72]);
+module p4215() /*[4215]*/ sc() {
+    dcore([4, 1, 1/6], [true, false, true]);
+    translate([0, 0, -64])
+        dcore([4, 1, 0], [false, true, false]);
+    translate([-40, 6, -72]) cube([80, 4, 72]);
+    translate([-40, -10, -4]) cube([80, 20, 4]);
 }
 
-module p4315() /*[4315]*/ render() {
-    basic([4, 1, 0]);
-    scale(sc) translate([0, -10, -4]) rotate([90, 0, 0]) hinge();
+module p4315() /*[4315]*/ sc() {
+    dcore([4, 1, 0]);
+    translate([0, -10, -4]) rotate([90, 0, 0]) hinge();
 }
 
-module p4600() /*[4600]*/ render() {
-    basic([2, 2, 0]);
-    scale(sc) for(i=[0, 1]) mirror([i, 0, 0]) {
-        mirror([0, 0, 1]) linear_extrude(8) translate([13, 0])
+module p4600() /*[4600]*/ sc() {
+    dcore([2, 2, 0]);
+    xmirror() {
+        downext(8) translate([13, 0])
             square([14, 4], center=true);
         translate([0, 0, -8]) linear_extrude(6)
             polygon([[20, -10], [22, -5], [22, 5], [20, 10]]);
         difference() {
             rotate([0, 90, 0]) translate([5, 0, 20]) {
-                cylinder(2, d=10);
-                cylinder(14, d=8);
-                translate([0, 0, 13]) cylinder(1, d=8.6);
+                linear_extrude(2) acir(10, 32);
+                linear_extrude(14) acir(8, 32);
+                translate([0, 0, 13])
+                    linear_extrude(1) acir(8.6, 32);
             }
             linear_extrude(20, center=true) hull()
                 for(i=[26.6, 35]) translate([i, 0])
-                    circle(d=1.3);
+                    acir(1.3, 32);
         }
     }
 }
 
-module p4624() /*[4624]*/ render() scale(sc) {
+module p4624() /*[4624]*/ sc() {
     difference() {
-        rotate([-90, 0, 0]) rotate_extrude() polygon([
+        rotate([-90, 0, 0]) rotate_extrude($fn=32) polygon([
             [0, 8], [10, 8], [10, 4], [8, 2],
             [8, -2], [10, -4], [10, -8], [0, -8]]);
         rotate([-90, 0, 0]) translate([0, 0, -2])
             linear_extrude(11) {
                 intersection() {
-                    circle(d=12);
+                    acir(12, 32);
                     for(i=[0, 90]) rotate(i)
                         square([20, 3], center=true);
                 }
-                circle(d=8);
+                acir(8, 32);
             }
         rotate([90, 0, 0]) translate([0, 0, 2])
-            cylinder(3, d=12);
+            cylinder(3, d=12, $fn=32);
         rotate([90, 0, 0]) translate([0, 0, 5]) difference() {
-            cylinder(3, d1=12, d2=16.7);
+            cylinder(3, d1=12, d2=16.7, $fn=32);
             linear_extrude(3) {
-                circle(d=8);
+                acir(8, 32);
                 for(i=[0, 90]) rotate(i)
                     square([20, 3], center=true);
             }
@@ -604,15 +735,18 @@ module p4624() /*[4624]*/ render() scale(sc) {
     }
 }
 
-module p6141() /*[6141]*/ render() scale(sc) {
-    stud(4, 12);
-    stud(3, 20, dir=-1);
-    stud(8, 16, 12, dir=-1);
+module p6141() /*[6141]*/ sc() {
+    fmirror() bstud();
+    downext(3) acir(20, 32);
+    downext(8) difference() {
+            acir(20*sqrt(2)-12);
+            acir(12);
+        }
 }
 
 module not_there() {
     echo("WARNING: Unknown part number!");
-    color("red") render() scale(sc) for(i=[90:90:360]) rotate(i)
+    color("red") sc() for(i=[90:90:360]) rotate(i)
         polyhedron([[-10, -10, -24], [-10, -10, -20],
                     [-10, -6, -24], [-10, -6, -20],
                     [-6, -10, -24], [-6, -10, -20],