Sand table v3: build fixes, bolted hub, counterweight, print guide

- print/ reorganised: v1-original (first export), v2-current, the v2.1-v2.7 fixes
  found while building, and v3/ with every printed part.
- v3: deck screws you can reach, seam joints from outside, arm bolted straight
  to the hub, 6804 hub bearings with a 15 mm bore for connectors, clamp collar,
  counterweight, 12.5 mm sand ring for a raised floor, Uno turnaround plate.
- print/README.md: full v3 parts list, what changed and why, assembly order.
- docs/: diagrams for each change.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/compose_guide.py

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+from PIL import Image, ImageDraw, ImageFont
+
+SRC = '/home/ckoch/ComfyUI/output/sandtable/step{}_00001_.png'
+OUT = '/home/ckoch/Documents/sandTable/docs/build-guide.png'
+F = '/usr/share/fonts/truetype/noto/NotoSans-{}.ttf'
+MONO = '/usr/share/fonts/truetype/dejavu/DejaVuSansMono.ttf'
+INK, GRAY, TEAL, RULE = (27, 36, 32), (90, 103, 98), (31, 128, 116), (214, 222, 218)
+
+STEPS = [
+    ("Shell and deck",
+     ["Join the 4 shell quarters at the seams.",
+      "Screw the 4 deck quarters onto the wall ledge. Deck Q1 (controller standoffs) goes under shell Q1 (cable notch)."],
+     "8x M3x16 + nuts  ·  8x M3x8 button"),
+    ("Center plate and hub",
+     ["Screw the center plate onto the deck.",
+      "Press the two 608 bearings into the housing, one from each side, and drop the hub shaft through."],
+     "8x M3x8 button  ·  2x 608"),
+    ("Slip ring (seen from below)",
+     ["Glue the adapter onto the bottom of the shaft, pressing up on the lower bearing: no play, still spins freely.",
+      "Push the printed coupler's 3 pegs into the adapter's holes (drop of CA); its slot slides over the top wires.",
+      "Only the slip ring's center boss turns: press it into the coupler's socket with a dab of gel CA. The flange stays free.",
+      "Slide the holder (part 27) up around the slip-ring body and onto the end of the tower; peg in a flange hole. Glue only its block to the tower."],
+     "CA glue  ·  coupler (26)  ·  holder (27)"),
+    ("Spin motor (seen from below)",
+     ["Hang the motor under the center plate with its 20T pulley, and loop the 200 mm belt over the hub.",
+      "Slide the motor in its slots to tension the belt, then tighten."],
+     "4x M3x12 socket"),
+    ("Arm",
+     ["Bolt the 220 mm extrusion to the hub, 80 mm behind center and 140 mm ahead.",
+      "Tip: idler bracket, 608 and sleeve. Back: motor bracket, arm motor, and the switch mount on top."],
+     "4x M5x12 socket  ·  3x M5x8  ·  7x T-nuts  ·  4x M3x6  ·  1x 608"),
+    ("Carriage",
+     ["Fit the 4 roller bearings with washers and slide the carriage on.",
+      "Loop the belt around the motor pulley and idler; clamp both ends in the carriage.",
+      "Magnets and spacer in the cup, felt on top, glue in. Glue the striker on the back edge."],
+     "5x M3x8 button  ·  4x 608  ·  2x magnets"),
+    ("Electronics (seen from below)",
+     ["Mount the Arduino + CNC shield under deck Q1, components facing down.",
+      "The arm motor (4 wires) and home switch (2 wires) run through the slip ring.",
+      "Fit all 3 microstep jumpers per driver and set each DRV8825's current before plugging in motors."],
+     "4x M3x6 socket"),
+    ("Close it up",
+     ["Test both axes with the floor off first.",
+      "Then the plexi floor, sand ring, about 4 mm of fine sand, the 3/8\" ball, and finally the glass."],
+     "~0.4 kg sand  ·  3/8\" steel ball"),
+]
+
+W, M, G = 2400, 80, 70
+PW = (W - 2 * M - G) // 2
+f_title = ImageFont.truetype(F.format('Bold'), 84)
+f_sub = ImageFont.truetype(F.format('Regular'), 34)
+f_step = ImageFont.truetype(F.format('Bold'), 46)
+f_num = ImageFont.truetype(F.format('Bold'), 40)
+f_body = ImageFont.truetype(F.format('Regular'), 31)
+f_hw = ImageFont.truetype(MONO, 27)
+f_hwl = ImageFont.truetype(F.format('Bold'), 25)
+f_foot = ImageFont.truetype(F.format('Regular'), 29)
+f_footb = ImageFont.truetype(F.format('Bold'), 29)
+
+
+def wrap(draw, text, font, width):
+    words, lines, cur = text.split(), [], ''
+    for w in words:
+        t = (cur + ' ' + w).strip()
+        if draw.textlength(t, font=font) <= width:
+            cur = t
+        else:
+            lines.append(cur)
+            cur = w
+    lines.append(cur)
+    return lines
+
+
+def panel(i, title, bullets, hw):
+    img = Image.open(SRC.format(i)).convert('RGB')
+    img = img.resize((PW, round(img.height * PW / img.width)), Image.LANCZOS)
+    tmp = ImageDraw.Draw(Image.new('RGB', (1, 1)))
+    body = []
+    for b in bullets:
+        body.append(wrap(tmp, b, f_body, PW - 40))
+    lh = 44
+    hw_lines, cur = [], ''
+    for tok in hw.split('  ·  '):
+        t = (cur + '  ·  ' + tok) if cur else tok
+        if tmp.textlength(t, font=f_hw) <= PW - 160:
+            cur = t
+        else:
+            hw_lines.append(cur)
+            cur = tok
+    hw_lines.append(cur)
+    h = 80 + img.height + 20 + sum(len(b) * lh + 10 for b in body) + 20 + 40 * len(hw_lines) + 10
+    p = Image.new('RGB', (PW, h), 'white')
+    d = ImageDraw.Draw(p)
+    d.ellipse((0, 4, 64, 68), fill=TEAL)
+    d.text((32, 36), str(i), font=f_num, fill='white', anchor='mm')
+    d.text((86, 36), title, font=f_step, fill=INK, anchor='lm')
+    y = 80
+    p.paste(img, (0, y))
+    y += img.height + 20
+    for lines in body:
+        d.ellipse((6, y + 15, 18, y + 27), fill=TEAL)
+        for ln in lines:
+            d.text((40, y), ln, font=f_body, fill=INK)
+            y += lh
+        y += 10
+    y += 14
+    d.text((0, y + 6), 'HARDWARE', font=f_hwl, fill=TEAL)
+    for ln in hw_lines:
+        d.text((150, y + 4), ln, font=f_hw, fill=GRAY)
+        y += 40
+    return p
+
+
+panels = [panel(i + 1, *s) for i, s in enumerate(STEPS)]
+rows = [panels[k:k + 2] for k in range(0, 8, 2)]
+head_h = 260
+foot_lines = [
+    ("Home switch: ", "use a KW12-B with a straight lever. Reprint the switch mount and glue on the striker from print/v2.1-switch-update."),
+    ("Fit first: ", "print 00-fit-test-coupon; every printed part is set for shaft 8.1 mm and bearing pocket 22.2 mm."),
+]
+foot_h = 70 + 50 * len(foot_lines) + 60
+H = head_h + sum(max(p.height for p in r) + 70 for r in rows) + foot_h
+canvas = Image.new('RGB', (W, H), 'white')
+d = ImageDraw.Draw(canvas)
+d.text((M, 70), 'Sand table build guide', font=f_title, fill=INK)
+d.text((M, 180), '12" polar kinetic sand table  ·  8 steps  ·  printed parts: print/v2-current + print/v2.1-switch-update', font=f_sub, fill=GRAY)
+y = head_h
+for r in rows:
+    d.line((M, y, W - M, y), fill=RULE, width=3)
+    y += 40
+    for k, p in enumerate(r):
+        canvas.paste(p, (M + k * (PW + G), y))
+    y += max(p.height for p in r) + 30
+d.line((M, y, W - M, y), fill=RULE, width=3)
+y += 40
+for b, t in foot_lines:
+    d.text((M, y), b, font=f_footb, fill=INK)
+    d.text((M + d.textlength(b, font=f_footb), y), t, font=f_foot, fill=INK)
+    y += 50
+d.text((M, y + 10), 'Drawings: renders of the SolidCraft model, restyled with Qwen-Image-Edit in ComfyUI.', font=f_foot, fill=GRAY)
+canvas.save(OUT, optimize=True)
+print(OUT, canvas.size)

docs/qwen_edit.py

@@ -0,0 +1,57 @@
+"""Restyle CAD renders with Qwen-Image-Edit-2511 (Lightning 8-step) through the local ComfyUI API."""
+import json, sys, time, urllib.request, random
+
+API = 'http://127.0.0.1:8188'
+
+STYLE = ("Redraw this 3D CAD render as a clean technical illustration for an assembly instruction manual. "
+         "Pure white background. Crisp dark outlines and flat soft shading, like a high-quality IKEA or LEGO instruction drawing. "
+         "Keep every part exactly where it is, with the same shapes, proportions, colors, camera angle and framing. "
+         "Do not add, remove, move or reshape any part. No text, no labels, no arrows, no numbers.")
+
+
+def workflow(image, prompt, prefix, seed):
+    return {
+        "1": {"class_type": "UNETLoader", "inputs": {"unet_name": "qwen_image_edit_2511_fp8mixed.safetensors", "weight_dtype": "default"}},
+        "2": {"class_type": "LoraLoaderModelOnly", "inputs": {"model": ["1", 0], "lora_name": "Qwen-Image-Edit-2511-Lightning-8steps-V1.0-bf16.safetensors", "strength_model": 1.0}},
+        "3": {"class_type": "ModelSamplingAuraFlow", "inputs": {"model": ["2", 0], "shift": 3.1}},
+        "4": {"class_type": "CFGNorm", "inputs": {"model": ["3", 0], "strength": 1.0}},
+        "5": {"class_type": "CLIPLoader", "inputs": {"clip_name": "qwen_2.5_vl_7b_fp8_scaled.safetensors", "type": "qwen_image"}},
+        "6": {"class_type": "VAELoader", "inputs": {"vae_name": "qwen_image_vae.safetensors"}},
+        "7": {"class_type": "LoadImage", "inputs": {"image": image}},
+        "8": {"class_type": "ImageScaleToTotalPixels", "inputs": {"image": ["7", 0], "upscale_method": "lanczos", "megapixels": 1.0, "resolution_steps": 16}},
+        "9": {"class_type": "TextEncodeQwenImageEditPlus", "inputs": {"clip": ["5", 0], "prompt": prompt, "vae": ["6", 0], "image1": ["8", 0]}},
+        "10": {"class_type": "TextEncodeQwenImageEditPlus", "inputs": {"clip": ["5", 0], "prompt": "", "vae": ["6", 0], "image1": ["8", 0]}},
+        "11": {"class_type": "VAEEncode", "inputs": {"pixels": ["8", 0], "vae": ["6", 0]}},
+        "12": {"class_type": "KSampler", "inputs": {"model": ["4", 0], "seed": seed, "steps": 8, "cfg": 1.0, "sampler_name": "euler",
+                                                     "scheduler": "simple", "positive": ["9", 0], "negative": ["10", 0],
+                                                     "latent_image": ["11", 0], "denoise": 1.0}},
+        "13": {"class_type": "VAEDecode", "inputs": {"samples": ["12", 0], "vae": ["6", 0]}},
+        "14": {"class_type": "SaveImage", "inputs": {"images": ["13", 0], "filename_prefix": prefix}},
+    }
+
+
+def run(image, prompt, prefix, seed=None):
+    seed = seed if seed is not None else random.randint(0, 2**31)
+    body = json.dumps({"prompt": workflow(image, prompt, prefix, seed)}).encode()
+    req = urllib.request.Request(API + '/prompt', data=body, headers={'Content-Type': 'application/json'})
+    pid = json.load(urllib.request.urlopen(req))['prompt_id']
+    t0 = time.time()
+    while True:
+        h = json.load(urllib.request.urlopen(f'{API}/history/{pid}'))
+        if pid in h:
+            st = h[pid].get('status', {})
+            if st.get('status_str') == 'error':
+                sys.exit(f'error: {json.dumps(st)[:2000]}')
+            outs = [img for node in h[pid]['outputs'].values() for img in node.get('images', [])]
+            if outs:
+                f = outs[0]
+                path = f"/home/ckoch/ComfyUI/output/{f['subfolder'] + '/' if f['subfolder'] else ''}{f['filename']}"
+                print(f'{image} -> {path}  ({time.time() - t0:.1f}s, seed {seed})', flush=True)
+                return path
+        time.sleep(1)
+
+
+if __name__ == '__main__':
+    jobs = json.loads(sys.argv[1])
+    for j in jobs:
+        run(j['image'], j.get('prompt', STYLE), j['prefix'], j.get('seed'))