Parameters to the keycap function

The following are the most interesting parameters to the main function in this function library, dmote-keycap.models.keycap.

• :style: One of :minimal or :maquette (see the readme).
• :switch-type: See below.
• :unit-size: A 2-tuple of horizontal size measured in u, hence non-linear. On a traditional ISO keyboard, the first value in this tuple (the width) varies from 1 for most keys to about 6 for a space bar. The second value (the depth) is 2 for the Enter key and 1 for all other keys. Please note that a non-rectangular shape, as is typical for the Enter key, is not yet supported by this library.
• :top-size: A 3-tuple describing the finger contact surface, including its thickness in the middle, directly above the stem of the keycap. The first two numbers in this 3-tuple can be omitted by replacing them with nil, in which case :slope (see below) will take precedence. All measurements in mm.
• :slope: A ratio between the top and bottom widths of the keycap. This setting is used to compute top size if :top-size is left incomplete, and to position legends on the sides of the cap.
• :top-rotation: A 3-tuple describing the angle of the finger contact surface, in radians. This would be [0 0 0] for a (row 3 or standard) DSA profile and would have a different non-zero first value for each row of an OEM profile.
• :bowl-radii: A 3-tuple describing the radii in mm of a spheroid used as negative space to carve a bowl out of the top of a non-maquette keycap. If this option is set to nil (CLI: 'nil nil nil'), the top is left flat.
• :bowl-plate-offset: An optional modification of the vertical distance in mm between the bowl and the top of the keycap.
• :skirt-thickness: The horizontal thickness of material in the outer walls of a minimal cap.
• :skirt-length: The length of material from the top of the stem down toward the switch mounting plate. By default, on a minimal cap, this is 1 mm less than the space available when the switch is pressed.
• :legend: Sources of and related parameters for 2D designs, documented here.
• :sectioned: If true, the model is cut in half for a sectioned view. This is useful in previews and development.
• :supported: If true, support structures are added underneath the model.
• :nozzle-width: The width of the printer nozzle that will be used to print the cap. This parameter is only used to build supports, which will have the width of the nozzle because this improves print speed and quality.
• :horizontal-support-height: The height of support structures added by :supported, where this are not already determined by the parts they support.
• :error-stem-positive, :error-stem-negative, :error-body-positive: Printer-dependent measurements of error for different parts of the cap. A breaking change is planned for version 1.0.0: All of these error values will default to zero to broaden support for different printing technologies.

Some of these parameters have global default values, while others have default values associated with particular styles, for ease of use. The long-term plan is to model a variety of traditional “families” with just a few parameters.

Parameters to the command-line application

Use lein run with command-line arguments corresponding to the parameters listed above. Not all parameters are supported; try lein run -- --help. The application will generate files of OpenSCAD code under output/scad and, optionally, STL files for slicing and 3D printing.

The CLI supports some additional parameters that are not interpreted by the keycap function inside the library. Here are some highlights:

• --batch: An alternative operating mode for multiple keys, documented here.
• --jig-mode: An alternative operating mode for a tool and no keys, documented here.
• --face-size: Rendering resolution.
• --filename: For your own CLI-based scripting needs.
• --render: Render results to STL under output/stl.
• --montage: With --render, render to PNG under output/png.

Montages include a view of all sides of all keys in a --batch.

Rendering requires OpenSCAD. Montages also require ImageMagick.

Switch types

dmote-keycap does not provide models of electromechanical switches, but it does contain some data on common types of switches, for shaping keycaps to fit. The following keywords are recognized for the switch type parameter mentioned above:

• :alps: ALPS-like designs, including Matias.
• :mx: Cherry MX and designs with very similar upper bodies.

The mx category covers, for example, Gateron’s KS-3 series and some of Kailh’s PG1511 series among other MX clones. However, the PG1511 series includes some models with shorter travel, and some types of stems (e.g. BOX) that will not fit with dmote-keycap.

Minor differences in the lower body of two types of switches, such as plate mount versus PCB mount, and lateral recesses on some MX-like switches but not on others, are not modelled by this library because they are irrelevant to keycaps. Version 0.7.0 of the DMOTE application introduced some support for additional switch types that are relevant to the mounting plate.