Add parametric CYD desk-stand case with DHT11 vent bay.

Provide OpenSCAD source, watertight front/back STLs, and print/assembly docs. Co-authored-by: Cursor <cursoragent@cursor.com>
2026-10-17 14:58:34 +08:00
parent eb21ec95eb
commit c35ed7a7a9
6 changed files with 575 additions and 0 deletions
--- a/README.md
+++ b/README.md
@@ -39,6 +39,20 @@ pio device monitor -b 115200
 | `cyd_28r_inv` | 颜色反相 / 发白 |
 | `cyd_28_st7789` | USB-C 双口 / ST7789 变体 |

+## 3D 外壳
+
+桌面斜立分体壳（前框 + 后盖支架 + DHT11 通风仓），可直接打印：
+
+- STL：[`cad/export/front.stl`](cad/export/front.stl)、[`cad/export/back.stl`](cad/export/back.stl)
+- 参数源 / 说明：[`cad/README.md`](cad/README.md)
+
+```bash
+pip install trimesh manifold3d numpy
+python cad/generate_stl.py
+```
+
+固定用 `4 × M3×10`；DHT11 装后盖通风仓，线接 CN1。
+
 ## 项目结构

 ```
@@ -46,6 +60,7 @@ platformio.ini                 # 板级与库依赖
 include/lv_conf.h              # LVGL 配置
 src/main.cpp                   # 仪表盘主程序
 scripts/exclude_lvgl_asm.py    # 排除 ESP32 不兼容的 LVGL ASM
+cad/                           # 3D 外壳（OpenSCAD + STL）
 .cursor/rules/                 # Cursor 协作规则
 README.md                      # 本文档
 ```
@@ -66,3 +81,4 @@ README.md                      # 本文档
 | 2026-10-17 | 初版：LVGL 仪表盘 + DHT11(GPIO22)，平滑/舒适度/趋势/背光 |
 | 2026-10-17 | 曾加入 ECO 熄屏休眠，后改回常亮正常版 |
 | 2026-10-17 | 初始化 Git，补充 README 与提交约定 |
+| 2026-10-17 | 新增 CYD+DHT11 桌面斜立 3D 外壳（OpenSCAD / STL） |
--- a/cad/README.md
+++ b/cad/README.md
@@ -0,0 +1,59 @@
+# CYD 温湿度仪表盘 3D 外壳
+
+桌面斜立分体外壳，适配 **ESP32-2432S028R（CYD）** + **DHT11（CN1 / GPIO22）**。
+
+## 零件
+
+| 文件 | 说明 |
+|------|------|
+| `export/front.stl` | 前框（屏窗 + 压边） |
+| `export/back.stl` | 后盖 + 斜立支脚 + DHT11 通风仓 |
+| `cyd_climate_case.scad` | 参数化源文件（OpenSCAD，可改尺寸） |
+| `generate_stl.py` | 无 OpenSCAD 时用 Python 导出 STL |
+
+## 设计要点
+
+- PCB 基准：`86 × 50 × 1.6` mm，四角安装孔
+- 前框可视窗约 `59.5 × 45` mm
+- 后盖背面净空约 7 mm；Micro-USB / USB-C 合并开孔
+- BOOT / RST 背面开孔；底部散热缝
+- **DHT11 独立通风仓**（后盖长边外侧），减少板温干扰；线槽通向 CN1
+- 固定：`4 × M3×10` 自攻进后盖塑料柱（孔径约 2.5 mm）
+
+## 打印建议
+
+| 参数 | 建议 |
+|------|------|
+| 材料 | PLA 或 PETG |
+| 层高 | 0.2 mm |
+| 喷嘴 | 0.4 mm |
+| 墙厚 | 2–3 圈 |
+| 填充 | 15–20% |
+| 支撑 | **不需要**（按 STL 默认朝向） |
+| 前框 | 屏窗朝上打印 |
+| 后盖 | 底板朝下，支脚伸出床外方向按切片预览摆放 |
+
+## 重新导出 STL
+
+```bash
+pip install trimesh manifold3d numpy
+python cad/generate_stl.py
+```
+
+或用 OpenSCAD：
+
+```bash
+openscad -o cad/export/front.stl -D part=\"front\" cad/cyd_climate_case.scad
+openscad -o cad/export/back.stl  -D part=\"back\"  cad/cyd_climate_case.scad
+```
+
+改尺寸：编辑 `cyd_climate_case.scad` / `generate_stl.py` 顶部参数后重新导出。
+
+## 装配
+
+1. DHT11 放入后盖通风仓，杜邦线经线槽接到 **CN1**（`3V3 / IO22 / GND`，按你现有接线）
+2. CYD 屏朝前框放入，USB 对齐侧孔
+3. 合上后盖，四角 M3×10 拧紧（勿过紧防裂）
+4. 桌面斜立放置；点屏可调背光
+
+若孔位与你的板子有 ±1 mm 偏差，优先改 `generate_stl.py` 里 `USB_Y` / `MH_INSET` 后重导。
--- a/cad/cyd_climate_case.scad
+++ b/cad/cyd_climate_case.scad
@@ -0,0 +1,300 @@
+/*
+ * CYD ESP32-2432S028R + DHT11 桌面斜立外壳
+ * Climate Dashboard Case — parametric OpenSCAD
+ *
+ * 零件：
+ *   part = "front"     前框（屏窗）
+ *   part = "back"      后盖 + 斜立支架 + DHT 通风仓
+ *   part = "assembly"  装配预览（半透明板子）
+ *
+ * 导出 STL（本机安装 OpenSCAD 后）:
+ *   openscad -o export/front.stl -D part=\"front\" cyd_climate_case.scad
+ *   openscad -o export/back.stl  -D part=\"back\"  cyd_climate_case.scad
+ */
+
+/* [Which part] */
+part = "assembly"; // ["front", "back", "assembly"]
+
+/* [PCB / CYD] */
+pcb_l = 86.0;
+pcb_w = 50.0;
+pcb_t = 1.6;
+pcb_corner_r = 4.0;
+mh_inset = 4.0;          // 安装孔距角边中心
+mh_dia = 3.2;            // PCB 孔
+
+/* [Display] */
+disp_l = 69.0;
+disp_w = 50.0;
+disp_h = 4.0;
+disp_x = 8.0;            // 屏相对 PCB 左边偏移
+view_l = 59.5;
+view_w = 45.0;
+view_inset_x = 7.0;      // 相对屏模组
+view_inset_y = 2.5;
+
+/* [Case shell] */
+wall = 2.4;
+gap = 0.4;               // 板与壳间隙
+front_lip = 1.2;         // 屏边压边宽度
+bezel_front_t = 2.0;     // 前框面板厚度
+cavity_back = 7.0;       // 背面元件净空
+stand_angle = 60;        // 桌面倾角（度，相对水平）
+stand_foot = 18;         // 支脚接触深度
+
+/* [USB dual cutout] */
+usb_dual = true;
+usb_w = 14.0;            // 双口合并开孔宽
+usb_h = 8.5;
+usb_y = 30.5;            // 相对 PCB 原点（短边为 X=0 侧）
+
+/* [Buttons] */
+btn_enable = true;
+btn_dia = 4.5;
+
+/* [DHT11 bay] */
+dht_enable = true;
+dht_bay_l = 22;
+dht_bay_w = 18;
+dht_bay_h = 14;
+dht_vent_slot = 1.6;
+dht_vent_gap = 2.8;
+
+/* [Screws] */
+screw_m3 = 3.2;
+boss_od = 7.2;
+boss_id = 2.6;           // 自攻进塑料
+$fn = 48;
+
+// ---- derived ----
+inner_l = pcb_l + 2 * gap;
+inner_w = pcb_w + 2 * gap;
+outer_l = inner_l + 2 * wall;
+outer_w = inner_w + 2 * wall;
+case_h = bezel_front_t + disp_h + pcb_t + cavity_back + wall;
+
+mh_pts = [
+  [mh_inset, mh_inset],
+  [pcb_l - mh_inset, mh_inset],
+  [pcb_l - mh_inset, pcb_w - mh_inset],
+  [mh_inset, pcb_w - mh_inset]
+];
+
+module rounded_rect(l, w, h, r) {
+  hull() {
+    for (x = [r, l - r], y = [r, w - r])
+      translate([x, y, 0]) cylinder(h = h, r = r);
+  }
+}
+
+module cyd_mock() {
+  color("gold")
+  difference() {
+    rounded_rect(pcb_l, pcb_w, pcb_t, pcb_corner_r);
+    for (p = mh_pts)
+      translate([p[0], p[1], -0.1])
+        cylinder(d = mh_dia, h = pcb_t + 0.2);
+  }
+  color("black")
+  translate([disp_x, 0, pcb_t])
+    cube([disp_l, disp_w, disp_h]);
+  color("navy")
+  translate([disp_x + view_inset_x, view_inset_y, pcb_t + disp_h])
+    cube([view_l, view_w, 0.2]);
+}
+
+// 前框：从屏面方向看，Z=0 为最前表面
+module front_bezel() {
+  view_x = wall + gap + disp_x + view_inset_x;
+  view_y = wall + gap + view_inset_y;
+
+  difference() {
+    union() {
+      // 前表面
+      rounded_rect(outer_l, outer_w, bezel_front_t, 3);
+      // 侧壁向下包住屏+PCB 前半
+      translate([0, 0, bezel_front_t])
+        difference() {
+          rounded_rect(outer_l, outer_w, disp_h + pcb_t * 0.5, 3);
+          translate([wall, wall, -0.1])
+            rounded_rect(inner_l, inner_w, disp_h + pcb_t + 1, 2);
+        }
+      // 止口（与后盖搭接）
+      translate([wall * 0.45, wall * 0.45, bezel_front_t + disp_h + pcb_t * 0.5 - 0.01])
+        difference() {
+          rounded_rect(outer_l - wall * 0.9, outer_w - wall * 0.9, 2.2, 2.4);
+          translate([wall * 0.55, wall * 0.55, -0.1])
+            rounded_rect(outer_l - wall * 2.0, outer_w - wall * 2.0, 3, 1.6);
+        }
+    }
+
+    // 可视窗
+    translate([view_x - 0.3, view_y - 0.3, -0.1])
+      cube([view_l + 0.6, view_w + 0.6, bezel_front_t + 1]);
+
+    // 屏模组沉台（背面）
+    translate([wall + gap + disp_x - 0.3, wall + gap - 0.2, bezel_front_t - 0.05])
+      cube([disp_l + 0.6, disp_w + 0.4, disp_h + 0.5]);
+
+    // 螺丝通孔
+    for (p = mh_pts)
+      translate([wall + gap + p[0], wall + gap + p[1], -0.1])
+        cylinder(d = screw_m3 + 0.2, h = case_h);
+  }
+
+  // 压屏边框内侧（窄边）
+  difference() {
+    translate([wall + gap + disp_x, wall + gap, bezel_front_t])
+      cube([disp_l, disp_w, 0.8]);
+    translate([view_x - 0.2, view_y - 0.2, bezel_front_t - 0.1])
+      cube([view_l + 0.4, view_w + 0.4, 2]);
+  }
+}
+
+// 后盖主体（不含支架倾转）；本地坐标：PCB 底面朝上放置时的壳
+module back_shell_body() {
+  shell_h = cavity_back + wall;
+  pcb_z = wall + cavity_back; // PCB 底面高度（元件朝下进腔）
+
+  difference() {
+    union() {
+      rounded_rect(outer_l, outer_w, shell_h, 3);
+
+      // 止口凹槽配合前框（外壳顶部一圈台阶）
+      translate([0, 0, shell_h - 0.01])
+        difference() {
+          rounded_rect(outer_l, outer_w, 2.0, 3);
+          translate([wall * 0.5, wall * 0.5, -0.05])
+            rounded_rect(outer_l - wall, outer_w - wall, 2.5, 2.4);
+        }
+
+      // 螺丝柱
+      for (p = mh_pts) {
+        translate([wall + gap + p[0], wall + gap + p[1], wall])
+          difference() {
+            cylinder(d = boss_od, h = cavity_back - 0.2);
+            translate([0, 0, 1])
+              cylinder(d = boss_id, h = cavity_back);
+          }
+      }
+
+      // DHT 通风仓（PCB 长边外侧，靠近 CN1：x≈51）
+      if (dht_enable) {
+        dht_x = wall + gap + 48;
+        dht_y = outer_w - wall * 0.2;
+        translate([dht_x, dht_y, wall])
+          dht_bay();
+      }
+    }
+
+    // 内腔
+    translate([wall, wall, wall])
+      rounded_rect(inner_l, inner_w, shell_h, 1.8);
+
+    // USB 开孔（短边 x=0 侧）
+    usb_cut_y = wall + gap + usb_y - usb_w / 2;
+    translate([-0.1, usb_cut_y, wall + 1.5])
+      cube([wall + 1.2, usb_w, usb_h]);
+
+    // SD 卡槽（可选宽缝）
+    translate([wall + gap + 28, outer_w - wall - 0.1, wall + 2])
+      cube([16, wall + 1, 3.2]);
+
+    // BOOT / RST 软按开孔（背面）
+    if (btn_enable) {
+      translate([wall + gap + 10, wall + gap + 12, -0.1])
+        cylinder(d = btn_dia, h = wall + 0.3);
+      translate([wall + gap + 10, wall + gap + 22, -0.1])
+        cylinder(d = btn_dia, h = wall + 0.3);
+    }
+
+    // 散热缝
+    for (i = [0:4])
+      translate([wall + 12 + i * 12, wall + 8, -0.1])
+        hull() {
+          cylinder(d = 2.2, h = wall + 0.3);
+          translate([0, 10, 0]) cylinder(d = 2.2, h = wall + 0.3);
+        }
+
+    // DHT 线槽通向 CN1
+    if (dht_enable) {
+      translate([wall + gap + 48, outer_w - wall - 2, wall + 2])
+        cube([8, wall + 4, 4]);
+    }
+  }
+}
+
+module dht_bay() {
+  // 局部：仓体贴在 outer 长边外侧
+  difference() {
+    translate([0, 0, 0])
+      rounded_rect(dht_bay_l, dht_bay_w + wall, dht_bay_h, 2);
+    translate([wall * 0.6, wall * 0.6, wall * 0.6])
+      cube([dht_bay_l - wall * 1.2, dht_bay_w, dht_bay_h]);
+
+    // 顶面百叶通风
+    for (i = [0:4])
+      translate([3 + i * dht_vent_gap, dht_bay_w * 0.3, dht_bay_h - wall - 0.1])
+        cube([dht_vent_slot, dht_bay_w * 0.55, wall + 0.3]);
+
+    // 侧面通风
+    for (i = [0:2])
+      translate([4 + i * 5.5, dht_bay_w + wall - 0.2, 3 + i * 0.2])
+        cube([dht_vent_slot, wall + 0.4, 6]);
+  }
+}
+
+// 带斜立支架的后盖（打印时支脚朝下）
+module back_with_stand() {
+  shell_h = cavity_back + wall;
+
+  // 后盖：PCB 元件朝下；支架使屏幕斜立
+  // 组装时：屏幕朝向 -Z 转 stand_angle
+  union() {
+    back_shell_body();
+
+    // 三角形支脚（沿 PCB 长边下方）
+    stand_len = outer_l * 0.72;
+    stand_x = (outer_l - stand_len) / 2;
+    // 支脚从后盖底面向后延伸
+    translate([stand_x, -stand_foot + 0.5, 0])
+      difference() {
+        cube([stand_len, stand_foot, shell_h]);
+        // 挖空减料
+        translate([2, 2, wall])
+          cube([stand_len - 4, stand_foot - 2, shell_h]);
+        // 斜切贴合桌面视觉（打印可平放）
+        translate([-0.1, 0, shell_h])
+          rotate([-stand_angle + 90, 0, 0])
+            cube([stand_len + 0.2, 40, 40]);
+      }
+
+    // 后支撑肋
+    translate([outer_l * 0.5 - 1.2, -stand_foot + 1, wall])
+      cube([2.4, stand_foot - 1, shell_h - wall - 1]);
+  }
+}
+
+module assembly() {
+  // 后盖在下
+  color("SteelBlue", 0.85) back_with_stand();
+
+  // PCB：元件朝下坐在腔顶
+  translate([wall + gap, wall + gap, wall + cavity_back])
+    rotate([180, 0, 0])
+      translate([0, -pcb_w, -pcb_t])
+        %cyd_mock();
+
+  // 前框盖上
+  translate([0, 0, wall + cavity_back + pcb_t + disp_h + bezel_front_t])
+    rotate([180, 0, 0])
+      translate([0, -outer_w, 0])
+        color("SlateGray", 0.7) front_bezel();
+}
+
+if (part == "front")
+  front_bezel();
+else if (part == "back")
+  back_with_stand();
+else
+  assembly();
--- a/cad/export/back.stl
+++ b/cad/export/back.stl
--- a/cad/export/front.stl
+++ b/cad/export/front.stl
--- a/cad/generate_stl.py
+++ b/cad/generate_stl.py
@@ -0,0 +1,200 @@
+#!/usr/bin/env python3
+"""Generate printable STL for CYD climate case using trimesh + manifold boolean."""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+import numpy as np
+import trimesh
+from trimesh.creation import box, cylinder
+
+# ---- mm, aligned with cyd_climate_case.scad ----
+PCB_L, PCB_W = 86.0, 50.0
+MH_INSET = 4.0
+DISP_L, DISP_W, DISP_H, DISP_X = 69.0, 50.0, 4.0, 8.0
+VIEW_L, VIEW_W, VIEW_IX, VIEW_IY = 59.5, 45.0, 7.0, 2.5
+WALL, GAP = 2.4, 0.4
+BEZEL_T, CAVITY = 2.0, 7.0
+PCB_T_HALF = 0.8
+USB_W, USB_H, USB_Y = 14.0, 8.5, 30.5
+STAND_FOOT = 18.0
+DHT_L, DHT_W, DHT_H = 22.0, 18.0, 14.0
+SCREW = 3.3
+BOSS_OD, BOSS_ID = 7.2, 2.5
+
+INNER_L = PCB_L + 2 * GAP
+INNER_W = PCB_W + 2 * GAP
+OUTER_L = INNER_L + 2 * WALL
+OUTER_W = INNER_W + 2 * WALL
+SHELL_H = CAVITY + WALL
+
+MH = [
+    (MH_INSET, MH_INSET),
+    (PCB_L - MH_INSET, MH_INSET),
+    (PCB_L - MH_INSET, PCB_W - MH_INSET),
+    (MH_INSET, PCB_W - MH_INSET),
+]
+
+
+def place(mesh: trimesh.Trimesh, center: tuple[float, float, float]) -> trimesh.Trimesh:
+    m = mesh.copy()
+    m.apply_translation(np.array(center) - m.bounding_box.centroid)
+    return m
+
+
+def aabb(x0, y0, z0, x1, y1, z1) -> trimesh.Trimesh:
+    dx, dy, dz = x1 - x0, y1 - y0, z1 - z0
+    m = box(extents=[dx, dy, dz])
+    m.apply_translation([x0 + dx / 2, y0 + dy / 2, z0 + dz / 2])
+    return m
+
+
+def u(*meshes: trimesh.Trimesh) -> trimesh.Trimesh:
+    result = meshes[0]
+    for m in meshes[1:]:
+        result = result.union(m, engine="manifold")
+    return result
+
+
+def d(a: trimesh.Trimesh, *subs: trimesh.Trimesh) -> trimesh.Trimesh:
+    result = a
+    for s in subs:
+        result = result.difference(s, engine="manifold")
+    return result
+
+
+def make_front() -> trimesh.Trimesh:
+    skirt_h = DISP_H + PCB_T_HALF
+    z1 = BEZEL_T + skirt_h
+
+    body = aabb(0, 0, 0, OUTER_L, OUTER_W, z1)
+    cavity = aabb(WALL, WALL, BEZEL_T, OUTER_L - WALL, OUTER_W - WALL, z1 + 1)
+
+    vx = WALL + GAP + DISP_X + VIEW_IX
+    vy = WALL + GAP + VIEW_IY
+    view = aabb(vx - 0.3, vy - 0.3, -0.5, vx + VIEW_L + 0.3, vy + VIEW_W + 0.3, BEZEL_T + 0.5)
+
+    # screen pocket
+    sx = WALL + GAP + DISP_X - 0.3
+    pocket = aabb(sx, WALL + GAP - 0.2, BEZEL_T - 0.05, sx + DISP_L + 0.6, WALL + GAP + DISP_W + 0.2, z1 + 0.5)
+
+    out = d(body, cavity, view, pocket)
+
+    for px, py in MH:
+        x = WALL + GAP + px
+        y = WALL + GAP + py
+        hole = cylinder(radius=SCREW / 2, height=z1 + 2, sections=32)
+        hole.apply_translation([x, y, z1 / 2])
+        out = d(out, hole)
+
+    out.merge_vertices()
+    return out
+
+
+def make_back() -> trimesh.Trimesh:
+    body = aabb(0, 0, 0, OUTER_L, OUTER_W, SHELL_H)
+    cavity = aabb(WALL, WALL, WALL, OUTER_L - WALL, OUTER_W - WALL, SHELL_H + 1)
+
+    # USB on -X
+    usb_y0 = WALL + GAP + USB_Y - USB_W / 2
+    usb = aabb(-1, usb_y0, WALL + 1.5, WALL + 1, usb_y0 + USB_W, WALL + 1.5 + USB_H)
+
+    # SD slot on +Y
+    sd = aabb(WALL + GAP + 28, OUTER_W - WALL - 1, WALL + 2, WALL + GAP + 44, OUTER_W + 1, WALL + 5.2)
+
+    # button holes on floor
+    btn1 = cylinder(radius=2.3, height=WALL + 2, sections=24)
+    btn1.apply_translation([WALL + GAP + 10, WALL + GAP + 12, WALL / 2])
+    btn2 = cylinder(radius=2.3, height=WALL + 2, sections=24)
+    btn2.apply_translation([WALL + GAP + 10, WALL + GAP + 22, WALL / 2])
+
+    # vent slots on floor
+    vents = []
+    for i in range(5):
+        v = aabb(WALL + 12 + i * 12, WALL + 8, -0.5, WALL + 14 + i * 12, WALL + 18, WALL + 0.5)
+        vents.append(v)
+
+    out = d(body, cavity, usb, sd, btn1, btn2, *vents)
+
+    # screw bosses
+    bosses = []
+    for px, py in MH:
+        x = WALL + GAP + px
+        y = WALL + GAP + py
+        boss = cylinder(radius=BOSS_OD / 2, height=CAVITY - 0.3, sections=32)
+        boss.apply_translation([x, y, WALL + (CAVITY - 0.3) / 2])
+        hole = cylinder(radius=BOSS_ID / 2, height=CAVITY + 1, sections=24)
+        hole.apply_translation([x, y, WALL + CAVITY / 2])
+        bosses.append(d(boss, hole))
+    out = u(out, *bosses)
+
+    # stand foot
+    stand_len = OUTER_L * 0.72
+    sx = (OUTER_L - stand_len) / 2
+    foot = aabb(sx, -STAND_FOOT + 0.5, 0, sx + stand_len, WALL, SHELL_H)
+    # hollow foot
+    foot_in = aabb(sx + 2, -STAND_FOOT + 2.5, WALL, sx + stand_len - 2, WALL - 0.2, SHELL_H + 1)
+    foot = d(foot, foot_in)
+    rib = aabb(OUTER_L * 0.5 - 1.2, -STAND_FOOT + 1, WALL, OUTER_L * 0.5 + 1.2, WALL, SHELL_H - 1)
+    out = u(out, foot, rib)
+
+    # DHT bay
+    dx = WALL + GAP + 48
+    dy = OUTER_W - 0.2
+    bay = aabb(dx, dy, WALL, dx + DHT_L, dy + DHT_W + WALL, WALL + DHT_H)
+    bay_in = aabb(dx + 1.2, dy + 1.2, WALL + 1.0, dx + DHT_L - 1.2, dy + DHT_W, WALL + DHT_H + 1)
+    # top vents
+    top_vents = []
+    for i in range(5):
+        tv = aabb(
+            dx + 2.5 + i * 3.6,
+            dy + 3,
+            WALL + DHT_H - WALL - 0.2,
+            dx + 2.5 + i * 3.6 + 1.5,
+            dy + DHT_W - 2,
+            WALL + DHT_H + 0.5,
+        )
+        top_vents.append(tv)
+    # side vents
+    for i in range(3):
+        sv = aabb(
+            dx + 4 + i * 5.5,
+            dy + DHT_W + WALL - 0.5,
+            WALL + 3,
+            dx + 4 + i * 5.5 + 1.5,
+            dy + DHT_W + WALL + 1,
+            WALL + 9,
+        )
+        top_vents.append(sv)
+    bay = d(bay, bay_in, *top_vents)
+
+    # cable channel from bay to CN1
+    channel = aabb(dx + 2, OUTER_W - WALL - 2, WALL + 2, dx + 10, OUTER_W + DHT_W, WALL + 6)
+    out = d(u(out, bay), channel)
+
+    out.merge_vertices()
+    return out
+
+
+def main() -> None:
+    out_dir = Path(__file__).resolve().parent / "export"
+    out_dir.mkdir(parents=True, exist_ok=True)
+
+    print("Building front…")
+    front = make_front()
+    print("Building back…")
+    back = make_back()
+
+    front.export(out_dir / "front.stl")
+    back.export(out_dir / "back.stl")
+
+    print(f"front: {front.faces.shape[0]} faces, watertight={front.is_watertight}")
+    print(f"back:  {back.faces.shape[0]} faces, watertight={back.is_watertight}")
+    print(f"Outer: {OUTER_L:.1f} x {OUTER_W:.1f} x front/back shells")
+    print(f"Wrote {out_dir / 'front.stl'}")
+    print(f"Wrote {out_dir / 'back.stl'}")
+
+
+if __name__ == "__main__":
+    main()