Repository navigation
Expand file tree
/
Copy pathindex.html
More file actions
568 lines (521 loc) · 39.5 KB
/
Copy pathindex.html
File metadata and controls
568 lines (521 loc) · 39.5 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
<title>bmesh-gear — Examples — Blender Developer Tools</title>
<meta name="description" content="A 14-tooth gear built entirely with bmesh — profile ring, face, extrude — with bm.free() in a try/finally, exactly as the ownership contract demands." />
<link rel="canonical" href="https://tmhsdigital.github.io/Blender-Developer-Tools/gallery/bmesh-gear/" />
<link rel="icon" href="../../assets/favicon.svg" type="image/svg+xml" />
<meta name="theme-color" content="#1a1b1e" />
<meta name="color-scheme" content="dark" />
<meta property="og:type" content="website" />
<meta property="og:title" content="bmesh-gear — Examples — Blender Developer Tools" />
<meta property="og:description" content="A 14-tooth gear built entirely with bmesh — profile ring, face, extrude — with bm.free() in a try/finally, exactly as the ownership contract demands." />
<meta property="og:url" content="https://tmhsdigital.github.io/Blender-Developer-Tools/gallery/bmesh-gear/" />
<meta property="og:image" content="https://tmhsdigital.github.io/Blender-Developer-Tools/gallery/assets/bmesh-gear-hero.webp" />
<meta property="og:image:width" content="1280" />
<meta property="og:image:height" content="720" />
<meta property="og:image:alt" content="bmesh-gear: the example's own headless render" />
<meta property="og:site_name" content="Blender Developer Tools" />
<meta name="twitter:card" content="summary_large_image" />
<meta name="twitter:title" content="bmesh-gear — Examples — Blender Developer Tools" />
<meta name="twitter:description" content="A 14-tooth gear built entirely with bmesh — profile ring, face, extrude — with bm.free() in a try/finally, exactly as the ownership contract demands." />
<meta name="twitter:image" content="https://tmhsdigital.github.io/Blender-Developer-Tools/gallery/assets/bmesh-gear-hero.webp" />
<meta name="twitter:image:alt" content="bmesh-gear: the example's own headless render" />
<style>
/* fonts are deployed by the landing build (docs/fonts/) */
@font-face { font-family: 'Barlow Condensed'; font-weight: 600; font-display: swap;
src: url('../../fonts/barlow-condensed-600.woff2') format('woff2'); }
@font-face { font-family: 'Inter'; font-weight: 400; font-display: swap;
src: url('../../fonts/inter-regular.woff2') format('woff2'); }
@font-face { font-family: 'Inter'; font-weight: 500; font-display: swap;
src: url('../../fonts/inter-medium.woff2') format('woff2'); }
@font-face { font-family: 'JetBrains Mono'; font-weight: 400; font-display: swap;
src: url('../../fonts/jetbrains-mono-regular.woff2') format('woff2'); }
/* Blender-viewport system, shared with the landing page. Dark only. */
:root {
color-scheme: dark;
--bg: #1a1b1e; --surface: #222327; --surface-2: #2a2b30; --bg2: #131417;
--border: #3a3b40; --text: #e8e9eb; --text-dim: #9698a0;
--select: #ff8c19; --ok: #6dc96d;
--radius: 4px; --radius-lg: 6px; --maxw: 1080px;
--font-display: 'Barlow Condensed', 'Arial Narrow', sans-serif;
--font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
--font-mono: 'JetBrains Mono', ui-monospace, 'SF Mono', Menlo, Consolas, monospace;
--code-k: #ff7b72; --code-s: #a5d6ff; --code-c: #9698a0; --code-n: #79c0ff;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body { font-family: var(--font-sans); background: var(--bg); color: var(--text);
line-height: 1.6; min-height: 100vh; -webkit-font-smoothing: antialiased; }
a { color: var(--select); text-decoration: none; }
a:hover { text-decoration: underline; }
:focus-visible { outline: 2px solid var(--select); outline-offset: 2px; border-radius: 3px; }
::selection { background: color-mix(in srgb, var(--select) 40%, transparent); }
.skip { position: absolute; left: -999px; top: 0; background: var(--select); color: #1a1b1e;
padding: 0.5rem 1rem; border-radius: var(--radius); z-index: 10; font-weight: 500; }
.skip:focus { left: 0.5rem; top: 0.5rem; }
.hud { font-family: var(--font-mono); font-size: 0.6875rem; letter-spacing: 0.04em;
color: var(--text-dim); text-transform: uppercase; }
.topbar { position: sticky; top: 0; z-index: 5; display: flex; align-items: center;
justify-content: space-between; gap: 1rem; padding: 0 1.25rem; height: 46px;
background: color-mix(in srgb, var(--surface) 92%, transparent);
backdrop-filter: blur(10px); border-bottom: 1px solid var(--border); }
.topbar .back { color: var(--text-dim); font-size: 0.8125rem; font-weight: 500; }
.topbar .back:hover { color: var(--select); text-decoration: none; }
.topbar-right { display: flex; align-items: center; gap: 0.85rem; }
.topbar-right .ghlink { color: var(--text-dim); font-size: 0.8125rem; font-weight: 500; }
.topbar-right .ghlink:hover { color: var(--select); text-decoration: none; }
header.hero { max-width: var(--maxw); margin: 0 auto; padding: 2.75rem 1.25rem 1.25rem; }
header.hero h1 { font-family: var(--font-display); font-weight: 600; text-transform: uppercase;
font-size: clamp(2.2rem, 5vw, 3.4rem); letter-spacing: 0.005em; line-height: 0.98; }
header.hero p { color: var(--text-dim); max-width: 62ch; margin-top: 0.7rem; font-size: 1rem; }
/* ---- index: sticky controls (search, density toggle, tag chips) ---- */
.controls { position: sticky; top: 46px; z-index: 4;
background: color-mix(in srgb, var(--bg) 94%, transparent);
backdrop-filter: blur(10px); -webkit-backdrop-filter: blur(10px);
border-bottom: 1px solid var(--border); }
.controls-inner { max-width: var(--maxw); margin: 0 auto; padding: 0.55rem 1.25rem 0.6rem;
display: flex; flex-direction: column; gap: 0.5rem; }
.controls-row { display: flex; align-items: center; gap: 0.6rem; flex-wrap: wrap; }
.searchwrap { position: relative; flex: 1 1 240px; min-width: 150px; }
.searchwrap input { width: 100%; background: var(--surface-2); border: 1px solid var(--border);
color: var(--text); border-radius: var(--radius); padding: 0.34rem 1.9rem 0.34rem 0.7rem;
font-family: var(--font-sans); font-size: 0.85rem; line-height: 1.4; }
.searchwrap input:focus { border-color: var(--select); outline: none; }
.searchwrap input::placeholder { color: var(--text-dim); }
.searchwrap input::-webkit-search-cancel-button { -webkit-appearance: none; appearance: none; }
.q-clear { position: absolute; right: 0.2rem; top: 50%; transform: translateY(-50%);
background: none; border: none; color: var(--text-dim); font-size: 1.05rem; line-height: 1;
cursor: pointer; padding: 0.25rem 0.45rem; border-radius: 3px; }
.q-clear:hover { color: var(--select); }
.count { font-family: var(--font-mono); font-size: 0.68rem; letter-spacing: 0.04em;
text-transform: uppercase; color: var(--text-dim); white-space: nowrap; }
.density { display: flex; border: 1px solid var(--border); border-radius: var(--radius);
overflow: hidden; }
.density-btn { background: var(--surface-2); border: none; color: var(--text-dim); cursor: pointer;
font-family: var(--font-mono); font-size: 0.68rem; letter-spacing: 0.04em;
text-transform: uppercase; padding: 0.36rem 0.7rem; transition: color 0.15s, background 0.15s; }
.density-btn + .density-btn { border-left: 1px solid var(--border); }
.density-btn:hover { color: var(--select); }
.density-btn.active { background: var(--select); color: #1a1b1e; }
.tags-toggle { display: none; background: var(--surface-2); border: 1px solid var(--border);
color: var(--text-dim); border-radius: 3px; padding: 0.3rem 0.7rem; cursor: pointer;
font-family: var(--font-mono); font-size: 0.7rem; letter-spacing: 0.04em; text-transform: uppercase; }
.tags-toggle:hover, .tags-toggle.has-active { color: var(--select); border-color: var(--select); }
/* Tag chips wrap by default (no-JS safe). With JS the row becomes a scroll
strip on wide viewports and collapses behind the Tags toggle on narrow
ones, so the sticky bar never eats the mobile viewport. */
.chips { display: flex; flex-wrap: wrap; gap: 0.4rem; }
html.js .chips { flex-wrap: nowrap; overflow-x: auto; padding-bottom: 0.25rem;
scrollbar-width: thin; scrollbar-color: var(--border) transparent; }
html.js .chips::-webkit-scrollbar { height: 5px; }
html.js .chips::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }
.chip { background: var(--surface-2); border: 1px solid var(--border); color: var(--text-dim);
border-radius: 3px; padding: 0.22rem 0.7rem; font-size: 0.72rem; font-weight: 400;
font-family: var(--font-mono); cursor: pointer; white-space: nowrap; flex: 0 0 auto;
transition: color 0.15s, border-color 0.15s; }
.chip:hover { color: var(--select); border-color: var(--select); }
.chip.active { color: #1a1b1e; background: var(--select); border-color: var(--select); }
@media (max-width: 719px) {
html.js .tags-toggle { display: inline-block; }
html.js .chips { display: none; }
html.js .chips.open { display: flex; flex-wrap: wrap; overflow-y: auto; max-height: 40vh; }
}
/* Compact density: hero + name + one-line teaser. The description and
WITNESSES text stay in the DOM (searchable, screen-reader reachable,
present with JS disabled when the class is never applied) but are
visually collapsed. Applied only by JS via the density-compact class. */
html.density-compact .grid { gap: 1rem; }
html.density-compact .card-body { padding: 0.65rem 0.9rem 0.7rem; }
html.density-compact .card-body h2 { font-size: 0.88rem; margin-bottom: 0.15rem; }
html.density-compact .teaches { font-size: 0.8rem; color: var(--text-dim); margin-bottom: 0;
white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
html.density-compact .witnesses { position: absolute; width: 1px; height: 1px; margin: -1px;
padding: 0; overflow: hidden; clip: rect(0 0 0 0); clip-path: inset(50%); white-space: nowrap; }
html.density-compact .card-link { display: none; }
.noresults { color: var(--text-dim); text-align: center; padding: 3rem 1rem; font-size: 0.95rem; }
.noresults .chip { margin-left: 0.6rem; }
.to-top { position: fixed; right: 1.25rem; bottom: 1.25rem; z-index: 6; cursor: pointer;
background: var(--surface-2); border: 1px solid var(--border); color: var(--text-dim);
border-radius: var(--radius); padding: 0.45rem 0.75rem;
font-family: var(--font-mono); font-size: 0.7rem; letter-spacing: 0.04em;
text-transform: uppercase; opacity: 0; visibility: hidden;
transition: opacity 0.2s, visibility 0.2s, color 0.15s, border-color 0.15s; }
.to-top.show { opacity: 1; visibility: visible; }
.to-top:hover { color: var(--select); border-color: var(--select); }
main { max-width: var(--maxw); margin: 0 auto; padding: 1rem 1.25rem 2rem; }
.grid { display: grid; grid-template-columns: 1fr; gap: 1.5rem; align-items: stretch; }
.card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius-lg);
overflow: hidden; display: flex; flex-direction: column;
outline: 2px solid transparent; outline-offset: -1px;
transition: outline-color 0.12s ease, border-color 0.12s ease; }
.card:hover { border-color: var(--select); outline-color: var(--select); }
.card.hidden { display: none; }
.card-media { display: block; background: var(--bg2); line-height: 0; }
.card-media img { display: block; width: 100%; aspect-ratio: 16 / 9; object-fit: cover; }
.card-body { padding: 1.15rem 1.4rem 1.45rem; display: flex; flex-direction: column; flex: 1 1 auto; }
.card-body h2 { font-family: var(--font-mono); font-size: 1rem; font-weight: 400; margin-bottom: 0.5rem; }
.card-body h2 a { color: var(--text); }
.card-body h2 a:hover { color: var(--select); text-decoration: none; }
.teaches { color: var(--text); margin-bottom: 0.7rem; font-size: 0.92rem; }
.witnesses { color: var(--text-dim); font-size: 0.85rem; margin-bottom: 1rem; }
.tag { display: inline-block; font-family: var(--font-mono); font-size: 0.62rem; text-transform: uppercase;
letter-spacing: 0.06em; color: var(--select); border: 1px solid color-mix(in srgb, var(--select) 55%, transparent);
border-radius: 3px; padding: 0.08rem 0.5rem; margin-right: 0.4rem; vertical-align: 1px; }
.card-link { font-weight: 600; font-size: 0.95rem; margin-top: auto; }
/* ---- detail page ---- */
.detail-hero { border: 1px solid var(--border); border-radius: var(--radius-lg); overflow: hidden;
background: var(--bg2); padding: 0; display: block; width: 100%; cursor: zoom-in; line-height: 0; }
.detail-hero img { display: block; width: 100%; aspect-ratio: 16 / 9; object-fit: cover; }
.zoom-hint { color: var(--text-dim); font-size: 0.78rem; margin-top: 0.4rem; }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0);
white-space: nowrap; }
.callout { border: 1px solid color-mix(in srgb, var(--select) 45%, var(--border));
border-left: 3px solid var(--select); border-radius: var(--radius);
background: color-mix(in srgb, var(--select) 7%, var(--surface));
padding: 0.85rem 1.1rem; margin: 1.5rem 0; font-size: 0.95rem; }
.runline { display: flex; align-items: stretch; gap: 0.5rem; margin: 1.5rem 0; }
.runline pre { flex: 1 1 auto; background: var(--surface-2); border: 1px solid var(--border);
border-radius: var(--radius); padding: 0.7rem 0.9rem; overflow-x: auto;
font-family: var(--font-mono); font-size: 0.83rem; line-height: 1.5; }
.copy-btn { flex: 0 0 auto; background: var(--surface-2); border: 1px solid var(--border);
color: var(--text-dim); border-radius: var(--radius); padding: 0 0.85rem; cursor: pointer;
font-family: var(--font-sans); font-size: 0.82rem; font-weight: 500; transition: color 0.15s, border-color 0.15s; }
.copy-btn:hover { color: var(--select); border-color: var(--select); }
.detail-section { margin-top: 2.25rem; }
.detail-section > h2 { font-family: var(--font-display); font-weight: 600; text-transform: uppercase;
font-size: 1.45rem; letter-spacing: 0.005em; padding-bottom: 0.5rem;
border-bottom: 1px solid var(--border); margin-bottom: 1rem; }
.md h1, .md h2, .md h3 { letter-spacing: -0.01em; margin: 1.4rem 0 0.6rem; line-height: 1.25; }
.md h1 { font-size: 1.35rem; } .md h2 { font-size: 1.15rem; } .md h3 { font-size: 1rem; }
.md p { margin: 0.7rem 0; }
.md ul, .md ol { margin: 0.7rem 0 0.7rem 1.4rem; }
.md li { margin: 0.3rem 0; }
.md .table-wrap { overflow-x: auto; margin: 0.9rem 0; }
.md table { border-collapse: collapse; font-size: 0.86rem; min-width: 100%; }
.md th, .md td { text-align: left; vertical-align: top; padding: 0.4rem 0.75rem 0.4rem 0;
border-bottom: 1px solid var(--border); }
.md th { color: var(--text-dim); font-weight: 600; white-space: nowrap; }
.md code { background: var(--surface-2); border: 1px solid var(--border); padding: 0.08rem 0.35rem;
border-radius: 4px; font-family: var(--font-mono); font-size: 0.84em; }
.md pre { background: var(--surface-2); border: 1px solid var(--border); border-radius: var(--radius);
padding: 0.85rem 1rem; overflow-x: auto; margin: 0.9rem 0; }
.md pre code { background: none; border: none; padding: 0; font-size: 0.83rem; line-height: 1.55; }
.src pre { background: var(--surface-2); border: 1px solid var(--border); border-radius: var(--radius);
padding: 1rem 1.1rem; overflow-x: auto; font-family: var(--font-mono);
font-size: 0.82rem; line-height: 1.55; }
.src .k { color: var(--code-k); } .src .s { color: var(--code-s); }
.src .c { color: var(--code-c); font-style: italic; } .src .n { color: var(--code-n); }
.src-meta { display: flex; justify-content: space-between; align-items: baseline; gap: 1rem;
flex-wrap: wrap; margin-bottom: 0.6rem; color: var(--text-dim); font-size: 0.85rem; }
.src-meta code { font-family: var(--font-mono); font-size: 0.82rem; }
.lightbox { border: 0; margin: 0; padding: 2rem; width: 100%; height: 100%; max-width: none;
max-height: none; background: rgba(0,0,0,0.85); cursor: zoom-out; }
.lightbox[open] { display: flex; align-items: center; justify-content: center; }
.lightbox::backdrop { background: transparent; }
.lightbox img { max-width: 100%; max-height: 100%; border-radius: var(--radius); }
.lightbox-close { position: absolute; top: 0.9rem; right: 0.9rem; background: var(--surface-2);
color: var(--text); border: 1px solid var(--border); border-radius: var(--radius);
font: 500 0.8rem var(--font-sans); padding: 0.4rem 0.75rem; cursor: pointer; }
.lightbox-close:hover { border-color: var(--select); color: var(--select); }
footer { border-top: 1px solid var(--border); background: var(--surface); margin-top: 2rem; }
footer .statusbar { max-width: var(--maxw); margin: 0 auto; padding: 0.55rem 1.25rem;
display: flex; align-items: center; gap: 1rem; flex-wrap: wrap;
font-family: var(--font-mono); font-size: 0.6875rem; letter-spacing: 0.04em;
text-transform: uppercase; color: var(--text-dim); }
footer .statusbar code { font-family: inherit; text-transform: none; }
@media (min-width: 720px) { .grid { grid-template-columns: 1fr 1fr; gap: 1.75rem; } }
@media (min-width: 560px) { html.density-compact .grid { grid-template-columns: 1fr 1fr; gap: 1rem; } }
@media (min-width: 900px) { html.density-compact .grid { grid-template-columns: repeat(3, 1fr); } }
@media (min-width: 1560px) {
html.density-compact .controls-inner,
html.density-compact main { max-width: 1400px; }
html.density-compact .grid { grid-template-columns: repeat(4, 1fr); }
}
@media (prefers-reduced-motion: reduce) {
html { scroll-behavior: auto; }
.card { transition: none; }
.card:hover { transform: none; }
.to-top { transition: none; }
}
</style>
</head>
<body>
<a class="skip" href="#main">Skip to content</a>
<div class="topbar">
<a class="back" href="../"><span aria-hidden="true">←</span> Examples and Showcase</a>
<div class="topbar-right">
<a class="ghlink" href="https://github.com/TMHSDigital/Blender-Developer-Tools">GitHub</a>
</div>
</div>
<header class="hero">
<h1>bmesh-gear</h1>
<p>A 14-tooth gear built entirely with bmesh — profile ring, face, extrude — with bm.free() in a try/finally, exactly as the ownership contract demands.</p>
</header>
<main id="main">
<button class="detail-hero" id="heroZoom" type="button" aria-label="Zoom bmesh-gear render">
<img src="../assets/bmesh-gear-hero.webp" alt="bmesh-gear render" width="1280" height="720" />
</button>
<p class="zoom-hint">Rendered headless by the example itself — click to zoom.</p>
<div class="callout"><span class="tag">witnesses</span> Parametric bmesh topology is exactly predictable: verts, edges, and faces match their closed forms, and every edge borders exactly two faces (watertight).</div>
<div class="runline">
<pre id="runCmd">blender --background --python examples/bmesh-gear/bmesh_gear.py --</pre>
<button class="copy-btn" id="copyRun" type="button">Copy</button>
</div>
<section class="detail-section md">
<p>A runnable example that builds a 14-tooth gear entirely with bmesh — profile ring, face, <code>extrude_face_region</code>, translate — following the ownership contract from <a href="https://github.com/TMHSDigital/Blender-Developer-Tools/tree/main/skills/mesh-editing-and-bmesh/SKILL.md"><code>mesh-editing-and-bmesh</code></a> and the <a href="https://github.com/TMHSDigital/Blender-Developer-Tools/tree/main/rules/always-free-bmesh.mdc"><code>always-free-bmesh</code></a> rule: every <code>bmesh.new()</code> is paired with <code>bm.free()</code> in a <code>try</code>/<code>finally</code>.</p>
<p><strong>What it witnesses:</strong> parametric bmesh construction has exactly predictable topology. The check asserts the closed-form counts — verts = 2 × (4 × teeth), faces = sides + 2 caps, edges = 3 × profile — and that the result is watertight (every edge borders exactly two faces). If an op leaks geometry or a face fails to close, the math catches it.</p>
<h2>Run</h2>
<pre><code># Cheap correctness check (no render) — the CI check:
blender --background --python bmesh_gear.py --
# Falsifier: skip the extrude. Must exit non-zero (topology).
blender --background --python bmesh_gear.py -- --no-extrude
# Also render a still (EEVEE on a GPU host; use --engine cycles on GPU-less hosts):
blender --background --python bmesh_gear.py -- --output gear.png
blender --background --python bmesh_gear.py -- --output gear.png --engine cycles</code></pre>
<h2>Exit codes</h2>
<p>Per-script sequential checks. <code>9</code> is a valid check code; there is no rule against it.</p>
<div class="table-wrap"><table><thead><tr><th scope="col">Code</th><th scope="col">Meaning</th></tr></thead><tbody><tr><td>0</td><td>Success</td></tr><tr><td>1</td><td>Uncaught exception (FATAL wrapper)</td></tr><tr><td>2</td><td>argparse / usage</td></tr><tr><td>3</td><td>Topology ≠ closed form (<code>--no-extrude</code> lands here)</td></tr><tr><td>4</td><td>Non-manifold edges</td></tr><tr><td>6</td><td><code>--output</code> produced no file</td></tr></tbody></table></div>
<p>The <code>blender-smoke</code> workflow runs the check on Blender 5.2 LTS and 4.5 LTS (5.1 on the weekly cron, the <code>needs-5.1</code> PR label, or manual dispatch). Smoke does not pass <code>--output</code> or <code>--no-extrude</code>.</p>
</section>
<section class="detail-section src">
<h2>Source</h2>
<div class="src-meta">
<code>examples/bmesh-gear/bmesh_gear.py</code>
<a href="https://github.com/TMHSDigital/Blender-Developer-Tools/tree/main/examples/bmesh-gear/bmesh_gear.py">View on GitHub →</a>
</div>
<pre><span class="s">"""A parametric gear built entirely with bmesh — a runnable example.
Witnesses the bmesh ownership contract from mesh-editing-and-bmesh and the
always-free-bmesh rule: every `bmesh.new()` is paired with `bm.free()` in a
`try`/`finally`, and because the construction is parametric the resulting
topology is exactly predictable. The check asserts the closed-form counts —
verts = 2 x (4 x teeth), faces = sides + 2 caps, edges = 3 x profile — and
that the mesh is watertight (every edge borders exactly 2 faces).
``--no-extrude`` skips the face-region extrude and still runs the closed-form
count check, so verts stay at one ring. That is the falsifier
(``--same-axis`` in export-preset-axis).
By default it runs only the correctness check (no render) — the CI smoke
check. Pass --output to also render a still:
blender --background --python bmesh_gear.py -- # check only
blender --background --python bmesh_gear.py -- --no-extrude # must fail
blender --background --python bmesh_gear.py -- --output g.png # + render
"""</span>
<span class="k">import</span> bpy, bmesh, sys, os, math, argparse
TEETH = <span class="n">14</span>
R_ROOT = <span class="n">1.0</span>
R_TIP = <span class="n">1.25</span>
DEPTH = <span class="n">0.6</span>
<span class="c"># fraction of a tooth period spent at the tip vs the root</span>
TOOTH_DUTY = <span class="n">0.45</span>
<span class="k">def</span> gear_profile():
<span class="s">"""Vertex ring for the gear silhouette: 4 verts per tooth (root-root-tip-tip)."""</span>
coords = []
step = <span class="n">2</span> * math.pi / TEETH
<span class="k">for</span> i <span class="k">in</span> range(TEETH):
a0 = i * step
half = step * TOOTH_DUTY / <span class="n">2</span>
flank = step * (<span class="n">0.5</span> - TOOTH_DUTY / <span class="n">2</span>) / <span class="n">2</span>
mid = a0 + step / <span class="n">2</span>
coords.append((a0 + flank, R_ROOT))
coords.append((mid - half, R_TIP))
coords.append((mid + half, R_TIP))
coords.append((a0 + step - flank, R_ROOT))
<span class="k">return</span> [(r * math.cos(a), r * math.sin(a), <span class="n">0.0</span>) <span class="k">for</span> a, r <span class="k">in</span> coords]
<span class="k">def</span> build_gear(no_extrude=<span class="k">False</span>):
bpy.ops.wm.read_factory_settings(use_empty=<span class="k">True</span>)
me = bpy.data.meshes.new(<span class="s">"Gear"</span>)
bm = bmesh.new()
<span class="k">try</span>:
verts = [bm.verts.new(co) <span class="k">for</span> co <span class="k">in</span> gear_profile()]
face = bm.faces.new(verts)
<span class="k">if</span> <span class="k">not</span> no_extrude:
ext = bmesh.ops.extrude_face_region(bm, geom=[face])
top_verts = [e <span class="k">for</span> e <span class="k">in</span> ext[<span class="s">"geom"</span>] <span class="k">if</span> isinstance(e, bmesh.types.BMVert)]
bmesh.ops.translate(bm, verts=top_verts, vec=(<span class="n">0.0</span>, <span class="n">0.0</span>, DEPTH))
bmesh.ops.recalc_face_normals(bm, faces=bm.faces)
bm.to_mesh(me)
<span class="k">finally</span>:
bm.free() <span class="c"># the contract this example witnesses</span>
obj = bpy.data.objects.new(<span class="s">"Gear"</span>, me)
bpy.context.collection.objects.link(obj)
<span class="k">return</span> obj
<span class="k">def</span> check(obj):
me = obj.data
profile = <span class="n">4</span> * TEETH
expect_v = <span class="n">2</span> * profile <span class="c"># bottom ring + extruded top ring</span>
expect_f = profile + <span class="n">2</span> <span class="c"># side quads + two caps</span>
expect_e = <span class="n">3</span> * profile <span class="c"># two rings + verticals</span>
got = (len(me.vertices), len(me.edges), len(me.polygons))
<span class="k">if</span> got != (expect_v, expect_e, expect_f):
print(<span class="s">f"</span><span class="s">ERROR: topology </span>{got}<span class="s"> != expected </span>{(expect_v, expect_e, expect_f)}<span class="s">"</span>,
file=sys.stderr)
<span class="k">return</span> <span class="n">3</span>
<span class="c"># watertight: every edge borders exactly two faces</span>
bm = bmesh.new()
<span class="k">try</span>:
bm.from_mesh(me)
bad = sum(<span class="n">1</span> <span class="k">for</span> e <span class="k">in</span> bm.edges <span class="k">if</span> len(e.link_faces) != <span class="n">2</span>)
<span class="k">finally</span>:
bm.free()
<span class="k">if</span> bad:
print(<span class="s">f"</span><span class="s">ERROR: </span>{bad}<span class="s"> non-manifold edge(s) — gear is not watertight</span><span class="s">"</span>, file=sys.stderr)
<span class="k">return</span> <span class="n">4</span>
print(<span class="s">f"</span><span class="s">teeth=</span>{TEETH}<span class="s"> verts=</span>{got[<span class="n">0</span>]}<span class="s"> edges=</span>{got[<span class="n">1</span>]}<span class="s"> faces=</span>{got[<span class="n">2</span>]}<span class="s"> watertight=True</span><span class="s">"</span>)
<span class="k">return</span> <span class="n">0</span>
<span class="k">def</span> eevee_engine_id():
<span class="k">return</span> <span class="s">'BLENDER_EEVEE'</span> <span class="k">if</span> bpy.app.version >= (<span class="n">5</span>, <span class="n">0</span>, <span class="n">0</span>) <span class="k">else</span> <span class="s">'BLENDER_EEVEE_NEXT'</span>
<span class="k">def</span> render_still(obj, path, engine):
scene = bpy.context.scene
<span class="k">for</span> poly <span class="k">in</span> obj.data.polygons:
poly.use_smooth = <span class="k">False</span> <span class="c"># crisp machined facets</span>
<span class="c"># machined brass: a flat metal face lit by area lights renders as one</span>
<span class="c"># featureless gradient, so the finish carries the design — concentric</span>
<span class="c"># turning marks (a RINGS wave driving roughness) break the face into</span>
<span class="c"># rings that each catch the key at a different angle</span>
mat = bpy.data.materials.new(<span class="s">"MachinedBrass"</span>)
mat.use_nodes = <span class="k">True</span>
nt = mat.node_tree
bsdf = nt.nodes[<span class="s">"Principled BSDF"</span>]
bsdf.inputs[<span class="s">"Base Color"</span>].default_value = (<span class="n">0.72</span>, <span class="n">0.44</span>, <span class="n">0.16</span>, <span class="n">1.0</span>)
bsdf.inputs[<span class="s">"Metallic"</span>].default_value = <span class="n">1.0</span>
rings = nt.nodes.new(<span class="s">"ShaderNodeTexWave"</span>)
rings.wave_type = <span class="s">'RINGS'</span>
rings.rings_direction = <span class="s">'SPHERICAL'</span> <span class="c"># concentric from center, not X-axis bands</span>
rings.inputs[<span class="s">"Scale"</span>].default_value = <span class="n">16.0</span>
rings.inputs[<span class="s">"Distortion"</span>].default_value = <span class="n">0.5</span>
rough = nt.nodes.new(<span class="s">"ShaderNodeMapRange"</span>)
rough.inputs[<span class="s">"From Min"</span>].default_value = <span class="n">0.0</span>
rough.inputs[<span class="s">"From Max"</span>].default_value = <span class="n">1.0</span>
rough.inputs[<span class="s">"To Min"</span>].default_value = <span class="n">0.14</span>
rough.inputs[<span class="s">"To Max"</span>].default_value = <span class="n">0.36</span>
nt.links.new(rings.outputs[<span class="s">"Fac"</span>], rough.inputs[<span class="s">"Value"</span>])
nt.links.new(rough.outputs[<span class="s">"Result"</span>], bsdf.inputs[<span class="s">"Roughness"</span>])
obj.data.materials.append(mat)
obj.location = (<span class="n">0.0</span>, <span class="n">0.0</span>, <span class="n">0.85</span>)
obj.rotation_euler = (math.radians(<span class="n">46</span>), <span class="n">0.0</span>, math.radians(<span class="n">22</span>))
floor_me = bpy.data.meshes.new(<span class="s">"Floor"</span>)
bm = bmesh.new()
<span class="k">try</span>:
bmesh.ops.create_grid(bm, x_segments=<span class="n">1</span>, y_segments=<span class="n">1</span>, size=<span class="n">30.0</span>)
bm.to_mesh(floor_me)
<span class="k">finally</span>:
bm.free()
fmat = bpy.data.materials.new(<span class="s">"Studio"</span>)
fmat.use_nodes = <span class="k">True</span>
fb = fmat.node_tree.nodes[<span class="s">"Principled BSDF"</span>]
fb.inputs[<span class="s">"Base Color"</span>].default_value = (<span class="n">0.03</span>, <span class="n">0.032</span>, <span class="n">0.037</span>, <span class="n">1.0</span>)
fb.inputs[<span class="s">"Roughness"</span>].default_value = <span class="n">0.7</span>
floor_me.materials.append(fmat)
floor = bpy.data.objects.new(<span class="s">"Floor"</span>, floor_me)
scene.collection.objects.link(floor)
wall = bpy.data.objects.new(<span class="s">"Wall"</span>, floor_me.copy())
wall.location = (<span class="n">0.0</span>, <span class="n">9.0</span>, <span class="n">0.0</span>)
wall.rotation_euler = (math.radians(<span class="n">90</span>), <span class="n">0.0</span>, <span class="n">0.0</span>)
scene.collection.objects.link(wall)
world = bpy.data.worlds.new(<span class="s">"World"</span>)
world.use_nodes = <span class="k">True</span>
<span class="c"># metals reflect the environment: keep a faint cool ambient so flanks never go black</span>
world.node_tree.nodes[<span class="s">"Background"</span>].inputs[<span class="s">"Color"</span>].default_value = (<span class="n">0.02</span>, <span class="n">0.022</span>, <span class="n">0.028</span>, <span class="n">1.0</span>)
scene.world = world
<span class="k">def</span> light(name, loc, energy, size, col, rot):
ld = bpy.data.lights.new(name, <span class="s">'AREA'</span>)
ld.energy = energy; ld.size = size; ld.color = col
ob = bpy.data.objects.new(name, ld)
ob.location = loc
ob.rotation_euler = tuple(math.radians(a) <span class="k">for</span> a <span class="k">in</span> rot)
scene.collection.objects.link(ob)
<span class="c"># metals live on reflections: soft warm key, restrained cool fill, and the</span>
<span class="c"># warm wedge raking the back wall (docs/VISUAL-STYLE.md)</span>
light(<span class="s">"Key"</span>, (-<span class="n">3.5</span>, -<span class="n">4.5</span>, <span class="n">5.5</span>), <span class="n">550.0</span>, <span class="n">4.5</span>, (<span class="n">1.0</span>, <span class="n">0.96</span>, <span class="n">0.9</span>), (<span class="n">48</span>, <span class="n">0</span>, -<span class="n">35</span>))
light(<span class="s">"Fill"</span>, (<span class="n">5.0</span>, -<span class="n">3.5</span>, <span class="n">2.5</span>), <span class="n">130.0</span>, <span class="n">9.0</span>, (<span class="n">0.75</span>, <span class="n">0.85</span>, <span class="n">1.0</span>), (<span class="n">65</span>, <span class="n">0</span>, <span class="n">50</span>))
light(<span class="s">"Wedge"</span>, (<span class="n">2.5</span>, <span class="n">5.5</span>, <span class="n">4.0</span>), <span class="n">380.0</span>, <span class="n">6.0</span>, (<span class="n">1.0</span>, <span class="n">0.76</span>, <span class="n">0.5</span>), (-<span class="n">68</span>, <span class="n">0</span>, <span class="n">190</span>))
<span class="c"># a small hot glint: brass needs one crisp specular streak to read machined</span>
light(<span class="s">"Glint"</span>, (<span class="n">1.8</span>, -<span class="n">5.2</span>, <span class="n">6.2</span>), <span class="n">900.0</span>, <span class="n">0.9</span>, (<span class="n">1.0</span>, <span class="n">0.9</span>, <span class="n">0.7</span>), (<span class="n">40</span>, <span class="n">0</span>, <span class="n">18</span>))
cam_data = bpy.data.cameras.new(<span class="s">"Cam"</span>)
cam_data.lens = <span class="n">55.0</span>
cam = bpy.data.objects.new(<span class="s">"Cam"</span>, cam_data)
cam.location = (<span class="n">0.0</span>, -<span class="n">7.6</span>, <span class="n">4.2</span>)
cam.rotation_euler = (math.radians(<span class="n">66</span>), <span class="n">0.0</span>, <span class="n">0.0</span>)
scene.collection.objects.link(cam)
scene.camera = cam
scene.render.engine = <span class="s">'CYCLES'</span> <span class="k">if</span> engine == <span class="s">'cycles'</span> <span class="k">else</span> eevee_engine_id()
<span class="k">if</span> engine == <span class="s">'cycles'</span>:
scene.cycles.samples = <span class="n">32</span>
<span class="k">else</span>:
<span class="k">try</span>:
scene.eevee.taa_render_samples = <span class="n">64</span>
<span class="k">except</span> AttributeError:
<span class="k">pass</span>
scene.render.resolution_x = <span class="n">1280</span>
scene.render.resolution_y = <span class="n">720</span>
scene.render.image_settings.file_format = <span class="s">'PNG'</span>
scene.render.filepath = path
<span class="c"># AgX would flatten the steel toward chalk (docs/VISUAL-STYLE.md)</span>
scene.view_settings.view_transform = <span class="s">'Standard'</span>
bpy.ops.render.render(write_still=<span class="k">True</span>)
<span class="k">return</span> os.path.exists(path) <span class="k">and</span> os.path.getsize(path) > <span class="n">0</span>
<span class="k">def</span> main():
argv = sys.argv[sys.argv.index(<span class="s">"--"</span>) + <span class="n">1</span>:] <span class="k">if</span> <span class="s">"--"</span> <span class="k">in</span> sys.argv <span class="k">else</span> []
p = argparse.ArgumentParser()
p.add_argument(<span class="s">"--output"</span>, default=<span class="k">None</span>, help=<span class="s">"optional: render a still PNG here"</span>)
p.add_argument(<span class="s">"--engine"</span>, default=<span class="s">"eevee"</span>, choices=(<span class="s">"eevee"</span>, <span class="s">"cycles"</span>),
help=<span class="s">"render engine for --output (cycles for GPU-less hosts)"</span>)
p.add_argument(<span class="s">"--no-extrude"</span>, action=<span class="s">"store_true"</span>,
help=<span class="s">"skip the face-region extrude (must fail)"</span>)
args = p.parse_args(argv)
obj = build_gear(no_extrude=args.no_extrude)
code = check(obj)
<span class="k">if</span> code:
<span class="k">return</span> code
<span class="k">if</span> args.output:
<span class="k">if</span> <span class="k">not</span> render_still(obj, os.path.abspath(args.output), args.engine):
print(<span class="s">"ERROR: render produced no file"</span>, file=sys.stderr)
<span class="k">return</span> <span class="n">6</span>
print(<span class="s">f"</span><span class="s">rendered still </span>{args.output}<span class="s">"</span>)
print(<span class="s">"bmesh-gear OK"</span>)
<span class="k">return</span> <span class="n">0</span>
<span class="k">if</span> __name__ == <span class="s">"__main__"</span>:
<span class="k">try</span>:
sys.exit(main())
<span class="k">except</span> Exception <span class="k">as</span> e:
<span class="k">import</span> traceback; traceback.print_exc(); print(<span class="s">f"</span><span class="s">FATAL: </span>{e}<span class="s">"</span>, file=sys.stderr); sys.exit(<span class="n">1</span>)
</pre>
</section>
</main>
<dialog class="lightbox" id="lightbox" aria-label="Full-size render">
<button class="lightbox-close" type="button" autofocus>Close</button>
<img src="../assets/bmesh-gear-hero.webp" alt="bmesh-gear render, full size" />
</dialog>
<footer>
<div class="statusbar">
<span>generated from <code>examples/gallery.json</code></span>
<span>CC-BY-NC-ND-4.0</span>
<span style="color: var(--ok);">exit 0</span>
</div>
</footer>
<script>
(function () {
var hero = document.getElementById('heroZoom');
var box = document.getElementById('lightbox');
if (hero && box) {
// <dialog>.showModal() traps focus, closes on Escape, and returns
// focus to the hero button on close. Any click inside closes it.
hero.addEventListener('click', function () { box.showModal(); });
box.addEventListener('click', function () { box.close(); });
}
var copy = document.getElementById('copyRun');
if (copy) {
copy.addEventListener('click', function () {
var cmd = document.getElementById('runCmd').textContent;
navigator.clipboard.writeText(cmd).then(function () {
copy.textContent = 'Copied!';
setTimeout(function () { copy.textContent = 'Copy'; }, 1500);
});
});
}
})();
</script>
</body>
</html>