Panel Tutorial

Note: This tutorial is for designing Rack v1 panels. For Rack v0.6 panels, see the Plugin Development Tutorial.


Install Inkscape, a cross-platform open-source vector graphics editor, to create SVG panels for Rack modules.

  • Create a new document.
  • Open the “Document Properties” panel (Shift+Ctrl+D), and make sure “Units” and “Display units” are set to “mm”.
  • Set the height to 128.5 mm and the width to a desired multiple of 5.08 mm (1 HP in Eurorack).

Designing your panel

Design the panel, or open an existing .pdf, .ai, .svg, etc file and copy-paste the contents into your new document.

Design recommendations from VCV:

  • Avoid gradients and photorealism. Use a flat style for panels and components. This increases clarity at all zoom levels, which is important when several other modules are on-screen.
  • Design panels as if you are designing hardware.
    • Make sure there is enough space between knobs and ports to put your thumbs between them.
    • Use an inverted background for output ports (see Fundamental VCO-1 panel above).
    • Labels should succinctly state the purpose of knobs, switches, and ports.
  • Roughly follow the graphical density and text sizes of Fundamental modules.

Copyright and trademark advice: Don’t use others’ intellectual property (IP) without their permission. It may be illegal and/or make the owner of the IP upset. Plugins which use other people’s work unfairly will not be accepted into the VCV Plugin Manager.

Don’t hesitate to ask the VCV community for design help. You may find several graphic designers seeking programmers for collaboration.

SVG limitations

The SVG standard is so broad, no renderer fully supports the entire format. Rack’s SVG renderer does not support the following features.

  • Text and fonts. All text objects must be converted to paths. This can be achieved in Inkscape with Path > Object to Path. As a benefit, this avoids license issues with embedding proprietary fonts.
  • Gradients. Simple two-color linear gradients may work, but more advanced features are not a priority since VCV recommends to avoid gradients altogether.
  • CSS. Although, most fill-* and stroke-* properties are supported in inline style attributes.

Adding components

A component is a graphical element that can be manipulated in C++. A component can be a param (knob, switch, button, slider), input, output, light, or a custom widget (e.g. an LED display drawn procedurally in C++).

The actual component graphic should not be included on the panel. Instead, add placeholders so that the script can generate C++.

  • Open the “Layers” panel (Ctrl+Shift+L), and create a layer named components.
  • For each desired component, create a particular shape on the components layer.
    • Use the circle tool (F5) to position a placeholder by its center. The size of the circle does not matter, only the center point. A create*Centered() function call is generated in C++.
    • Use the rectangle tool (F4) to to position a placeholder by its top-left point. This should only be used when the component’s size needs to be defined on the panel, such as a rectangular LED display. A create*() function call is generated in C++.
  • Set the color of each shape depending on the component’s type.
    • Param: red #ff0000
    • Input: green #00ff00
    • Output: blue #0000ff
    • Light: magenta #ff00ff
    • Custom widgets: yellow #ffff00
  • To save time editing the .cpp file later, you may name each component to automatically generate names in C++. Open the “Object Properties” panel (Shift+Ctrl+O), select a component placeholder, and type in the “Label” field. Note that you must press “Set” or Enter to apply the new name.
  • Hide the components layer using the “Layers” panel and save the file to res/<module slug>.svg.

Run <Rack SDK>/ createmodule <module slug> to automatically convert your panel into a template .cpp source file.