Thin mATX PicoPSU Case

A fully parametric, 3D-printable case for a micro-ATX motherboard (originally designed around an ASUS H81M-C), a PicoPSU, and a low-profile CPU cooler — no expansion cards, as thin as the I/O shield allows.

Real prints

Written as a single OpenSCAD file. Every dimension — board size, wall thickness, I/O shield position, standoff pins, vents, front panel holes — is a named variable near the top of case.scad, so it can be re-fit to a different board without touching the geometry logic.

What's included

• Base tray — perimeter ledge (widened on one side to match a real fit-check), retention tabs, standoff pins across the floor, chamfered underside/topside flanges (prints with no supports), rear I/O cutout, front DC jack hole, rear power-switch hole, optional floor vents (hex or slit style).
• Lid — vented, corners rounded to match the screw-post radius.
• I/O opening test coupon — a small flat frame with just the I/O cutout, for a fast test print before committing to the full tray.
• Ledge fit test coupon — a small corner sample (wall + ledge + chamfer + retention tab) to test-fit a real board corner before a full print.

Pre-generated STLs for all four are in stl/. They match whatever case.scad currently contains — regenerate them (see below) after changing any parameter.

Printing

Open case.scad in OpenSCAD and use the Customizer panel (Window menu → Customizer) to check exactly one of these boxes, then F6 (Render) → File → Export → Export as STL:

• show_base
• show_lid
• show_io_test
• show_ledge_test

Or from the command line:

openscad -D 'part="base"'       -o base.stl        case.scad
openscad -D 'part="lid"'        -o lid.stl          case.scad
openscad -D 'part="io_test"'    -o io_test.stl      case.scad
openscad -D 'part="ledge_test"' -o ledge_test.stl   case.scad

All pieces are oriented to print flat with no supports.

Fitting to your own board

Everything is driven by named variables at the top of case.scad:

Section	Covers
Board dimensions	board_w, board_d, board_t, gap
Case shell	wall, standoff_h, top_clear, floor_t, lid_t
I/O shield	shield_w, shield_h, io_margin_left/right/top/bottom, shield_offset_from_board_left, rim_above
Ledge / board retention	ledge_w, ledge_w_left, ledge_t, board_clearance, tab_h
Standoff pins	add_standoff_pins, pin_d, pin_h, pin_pitch, pin_margin
Floor vents	floor_vents, floor_vent_style ("hex"/"slit"), margins, size/pitch
Front/rear panel holes	dc_jack_d/x/z, pwr_btn_d/x/z
Corner posts / lid	ear, post_d

Re-measure your board's I/O shield position the same way this one was calibrated: lay a ruler along the rear edge and down the shield height in a couple of photos, then adjust shield_offset_from_board_left and the io_margin_* values to match.

License

GPL-3.0 — see LICENSE.