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JST Connector Studio: manufacturer 3D mate editor

Public Unreviewed

by John Lauer

Interactive Babylon 9.5 studio for JST wire-to-board connectors: load a system (PH/XH/SH/GH/ZH), see the JST manufacturer housing+wire+ds2sf footprint mate in a looping animation next to the KiCad hou

hardwareconnectorjstcadkicad3dfootprintwire-to-board
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name: jst-connector-cad description: Source JST connector manufacturer CAD (email-gated STEP) and build interactive, animated, footprint-accurate wiki component pages — board+wire mate animation, true-scale pads registered to real pins, KiCad-vs-JST comparison, and the Babylon-viewer gotchas. Use when working with JST connectors, manufacturer 3D/STEP, ds2sf footprints, or animated GLB component pages.

JST connector CAD — manufacturer 3D + animated mating component pages

A reproducible recipe for sourcing JST connector CAD the manufacturer-first way and turning it into an interactive, animated, footprint-accurate wiki component page. Built and verified end-to-end (PH/XH/SH/GH/ZH 2-circuit systems).

The point of chip-fetcher: the 3D model is the manufacturer's (JST's own STEP). KiCad is used only for the redistributable symbol/footprint and as a side-by-side comparison foil — never as the 3D deliverable.

1. Get the manufacturer CAD (email-gated)

JST gates STEP downloads behind an email form on jst-mfg.com, and jst.com (USA) Cloudflare-walls headless browsers. Drive the user's real browser (native-browser bridge), fill the License Agreement form, and retrieve the emailed STEP via the Gmail API (adom-google). One submit per file; dedupe; trash demo emails. Full flow: chip-fetcher playbooks jst.md + jst-email-retrieval.md.

For each 2-circuit system you want three real parts: board header, wire housing, crimp contacts — plus the KiCad symbol/footprint (and KiCad 3D if it exists).

2. Mating orientation (which way the wire goes in)

Encoded in the part number AND the datasheet drawing:

  • B… (B2B, BM) = top entry → wire mates straight down (+Z).
  • S… (SM, S2B) = side entry / right-angle → wire mates horizontally (+Y).

3. STEP → GLB

step2glb convert each STEP. It emits Draco-compressed GLB that trimesh can't read — decompress with @gltf-transform (unpartition + dispose KHR_draco_mesh_compression). Use step2glb features / thumbnail --pose front|top|side to read each model's pin axis; KiCad models are reliably Z-up, pins −Z (identity), JST THT boards here needed R_x(+90).

4. Compose the scene (trimesh) — the part that matters

Two columns: KiCad foil (tan/grey) | JST manufacturer (blue). One column if KiCad has no 3D.

Seat the body, not the bbox. The connector's body bottom (where the cross-section widens above the thin pins) sits on the PCB top. Seating by bbox.min sinks the housing into the PCB. Detect body-bottom by walking z-slices for the first wide slice.

True-scale footprint pads, registered to the real pins. Do not paste the footprint as a scaled image — its pads won't land on the pins. Parse the .kicad_mod, render copper pads (THT = ring + drill hole, SMT = roundrect) at real mm coords, then register: detect the connector's pin centroid + axis from the mesh's lowest band and rotate/translate the pads onto them. Validate numerically: pad_pitch == pin_pitch (e.g. PH 2.0 == 2.0). This is what makes pins land in holes:

True-scale pads + readable nameplates

Float the PCB; show pins through. Render the PCB as a thin (~1.6 mm) slab at ~8 mm, no riser (a riser hides the underside). THT boards seat with pins through the slab and protruding out the bottom. Drop a tiny (~0.3 mm) invisible anchor at z=0 so the viewer (which grounds to the lowest geometry) puts the floor low and you can look under the PCB:

Pins pass through the PCB to the underside

If KiCad has no 3D model (e.g. ZH B2B-ZR → kicad-packages3d 404), don't silently drop the column — stand a red "KiCad: no 3D model" placard in its slot:

ZH: KiCad-absent placard + JST mate

5. Animate (GLB node channels)

Name the board/wire nodes; bake geometry at the seated pose (node base TRS = seated, so a non-animating viewer still looks right). Add an animation with @gltf-transform (createAnimationSampler/createAnimationChannel, path translation, LINEAR): board descends so pins pass through, then the wire inserts ~80% into the board body (shows JST's contact slots). Keep lifts small; dwell long on the fully-mated state (the money shot), quick reset, loop. The Babylon viewer autoplays + loops embedded GLB animations — no play button.

6. Babylon-viewer gotchas (these cost real time — verify, don't assume)

  • ALWAYS screenshot your own generated 3D view in the live viewer and READ it. matplotlib renders geometry but not textures/text, so it will not reveal mirrored/upside-down labels or texture issues. Only the real Babylon viewer tells the truth.
  • The 3D viewer is an <iframe> (/viewer/3d/component/<slug>). Reloading the parent page does not refresh the iframe's cached GLB. Bump the GLB filename (-vN.glb) and/or set iframe.src += '?cb=…'.
  • Texture orientation: on these quads Babylon maps UV so image-top lands at the quad bottom (use uv [[0,1],[1,1],[1,0],[0,0]] for upright) and flips U on the camera-facing face (pre-mirror the image with ImageOps.mirror). For two-sided labels use separated single-winding quads (coplanar double-winding z-fights), both pre-mirrored, backed opaque (transparent PNGs bleed through).
  • bbox-check everything and print it: body-bottom on PCB top, pins protrude, pad_pitch == pin_pitch, wire above PCB. Cheap asserts catch the geometry bugs.
  • Publish: components/skills are org-owned — adompkg publish --org adom (publishing as your user 409s).

Live examples (the 5 built with this recipe)

B2B-PH-K-S (PH 2.0) · B2B-XH-A (XH 2.5) · SM02B-SRSS-TB (SH 1.0, side-entry) · BM02B-GHS-TBT (GH 1.25 SMT) · B2B-ZR (ZH 1.5, no KiCad 3D)

See also: chip-fetcher.