STL to print, STEP for CAD, IGS for surfaces, GLB for the web: the Files menu offers eleven exports. Here is which one to take, and why.

The settings that make the blade manufacturable

A calculated propeller is only worth something once it leaves the software. Heliciel offers eleven exports; they are not equivalent, and the wrong choice is paid for in hours of rework in CAD or in an unusable printed part.

1: Choosing the format by use

• 3D printing: STL, or OBJ if your toolchain prefers it. These are facet meshes: the definition is fixed at export time;
• Picking the model up in parametric CAD (assembly, hub, keyway): STEP. The model comes out as one geometric set per body;
• Obtaining smooth surfaces for machining or shape rework: IGS;
• Showing the propeller to a customer, a manufacturer, a panel: GLB, which opens in any 3D viewer and can be published as it stands on a web page;
• Cutting and assembling the blade from plates: this is not a 3D export but a kit — see the dedicated page.

The eleven export entries of the Files menu

2: IGS, and the question of scale

The IGS export gives surfaces of high smoothing quality. Its frame is fixed and worth knowing: X axis = rotation axis, Y axis = blade axis, origin at the intersection of the two.

Two scales are offered. Scale 1 suits most projects; scale 10 exists for small-diameter propellers, whose definition suffers from the rounding of the format: the model comes out ten times larger, and scaling by 0.1 in CAD restores the size.

The two scales of the IGS export

3: STEP, for CAD

Two entries: complete propeller and propeller without hub. The second is used when the hub is a part of your own design — shaft, cone, variable pitch mechanism — and you only want to import the blades.

4: STL, and its five variants

Complete propeller, propeller without hub (for annular ducts), single blade, cyclic part — the repeating angular sector, useful for the calculation as well as for manufacturing — and duct. OBJ is available for the complete propeller and for the duct.

5: GLB, to show without installing anything

The .glb file is binary glTF 2.0: it opens in off-the-shelf 3D viewers and is published directly on a web page. It is the format to send when the recipient has no CAD package — and does not have to install one to turn around your propeller.

6: What the export carries — and what is set elsewhere

An export only translates the geometry of the project. Four points are worth knowing:

• the rounded blade tip and the root fillet are carried by the STL, OBJ, STEP and GLB exports; they are set in the blade dimensions tab — see the dedicated page;
• the hub taper is derived from the rake, the hub staying perpendicular to the generatrix at the blade root, as on a real propeller;
• the exported trailing edge thickness is 0.5 % of the mean chord of the blade — a manufacturing thickness, identical at every radial station. The blend is progressive from 70 % of the chord onwards: the leading edge and the mid-chord, which carry the suction peak, are never touched;
• the direction of rotation of the project is respected: a left-handed propeller exports left-handed — see the conventions.

Going further: the plate blade kit, the generatrix and the surfaces, and the 3D prototype on screen.