Pick a Preset
Open CAD Mode and use the Preset dropdown to choose what you are making. Each preset exposes a different parameter set:
Bolt
Hex-headed bolt with shaft diameter, total length, head diameter, head height, and a Segments control for the cylinder smoothness. Defaults match a chunky M8 × 35.
Nut
Hexagonal nut with outer diameter (across flats), through-hole diameter, and height. The nut and bolt share defaults so you can pair them out of the box.
L Bracket
Right-angle bracket with width, height, depth, plate thickness, and mounting-hole diameter. Includes a triangular gusset rib for stiffness on long arms.
Open Box
Rectangular open-top box with width, depth, height, and uniform wall thickness. Drop-in storage for screws, dice, hardware bins, drawer organisers.
Dial In the Numbers
Every parameter is a numeric input — type the value or use the up/down arrows. The 3D viewer rebuilds the part on every change, so you see the result instantly. The status line under the buttons shows the part type and triangle count, so you know roughly how heavy the export will be.
- For threaded parts, leave a little clearance: a 8 mm bolt usually pairs with a 8.4–8.6 mm hole on FDM, depending on flow calibration.
- Bump Segments from 64 to 96 or 128 for smooth-looking shafts at the cost of more triangles — only worth it on visible cosmetic parts.
- For brackets, set Thickness at 4× your line width or higher (5 mm at 0.4 mm nozzle is comfortable). Anything thinner flexes.
Export — STL or OpenSCAD
Two export buttons sit next to Generate:
⇓ STL
Exports a binary STL of the live preview, ready to drop into Slicer Pro, Cura, OrcaSlicer, Bambu Studio, or PrusaSlicer. Filename includes the preset name (mega-slicer-cad-bolt.stl, etc.) so they do not collide in your downloads folder.
⇓ SCAD
Exports the underlying OpenSCAD source. Open it in OpenSCAD if you want to keep editing parametrically — combine multiple parts, add chamfers, fillet edges, or version-control the whole thing in git.
The OpenSCAD source is also visible inline. Click OpenSCAD code in the panel and you will see something like:
$fn=64;
shaft_d=8;
shaft_l=35;
head_d=13;
head_h=5;
module hex_head(d,h){
cylinder(d=d, h=h, $fn=6);
}
union(){
cylinder(d=shaft_d, h=shaft_l);
translate([0,0,shaft_l]) hex_head(head_d, head_h);
}
Pro Tip — Keep the SCAD
If you are designing parts that will evolve (a project enclosure, a fixture set), export the SCAD as well as the STL. Future-you will thank present-you when the customer says “same thing, but 3 mm wider” and you can re-render in seconds instead of rebuilding from sliders.
Print Settings That Just Work
The presets are designed for FDM printability. A few pointers that apply across the board:
- Bolts — print head-down (head on the bed). The hex flats give plenty of bed contact and the shaft prints up cleanly with no supports.
- Nuts — print flat. The hex profile bridges across the through-hole easily; no supports needed.
- L brackets — print with the inside corner facing the bed. The gusset rib then prints in tension rather than as an overhang.
- Open boxes — vase mode is tempting, but real boxes need 2–3 perimeters and 0–5% infill so the bottom does not warp.
- For high-stress hardware, raise walls / perimeters to 4 or 5 in your slicer. Solid prints fail at the layer line; thicker walls hide that line inside the part.
Pairs Well With…
CAD Mode is the front of a workflow, not the end of one. Common follow-ups:
- Use DowelPro to add precision dowel pins to a generated bracket if you are joining two halves of a larger assembly.
- Run brackets through the Orientation Optimizer if the gusset geometry makes the “obvious” orientation non-obvious.
- Drop the open-box export into Build Plate Packer to fit a dozen storage bins on one plate.
- Estimate filament cost with the Mega Estimator before committing to a 200-bracket batch.