Overdraw is a free and open source VST3®/AU audio plug-in that implements a waveshaper in which the user can
draw the transfer function of each channel using splines.
Here is a brief video with an example of Overdraw and
Curvessor used together.
You can jump to
the download section, or browse
the
source code.
Features
- The transfer functions are smoothly automatable splines.
- Resizable UI (NEW in version 1.2)
- Optional Mid/Side Stereo processing.
- All the parameters, including the knots of the spline, can have different values on the Left
channel and on the Right channel
- or on the Mid channel and on the Side channel, when in Mid/Side Stero Mode.
- Dry-Wet percentage.
- Up to 32x Oversampling with either Minimum Phase or Linear Phase Antialiasing.
- VU meter showing the difference between the input level and the output level.
- Customizable smoothing time, used to avoid zips when automating the knots of the splines, the wet
amount, the smoothing time, or the input and output gains
Spline editing
The splines can be edited either by dragging the knots with the mouse, or by entering numeric
values for the selected knot.
To enable or disable a knot, double click on it.
When the knots of two different channel are overlapping, the mouse will interact with the control
point of the Left/Mid channel.
To interact with the knot of the Right/Side channel, use the right button of your mouse, or press the
ALT key while clicking.
To zoom in or out, use the mouse scroll wheel.
Supported Platforms
Overdraw is developed and tested on Windows (VST3) and macOS (VST3 and AudioUnit).
If you are willing to build Overdraw from the source code, you may also be able to build a VST3 binary for Linux.
If you encounter any issue, please contact me on
GitHub.
Previous versions
Overdraw 1.2 was built on 2026/05/10.
Click
here if you are interested in the old version
of Overdraw.
Acknowledgements
Overdraw includes code from these third party libraries:
- The JUCE cross platform C++
framework.
- r8brain: an high-quality pro
audio sample rate converter / resampler C++ library by Aleksey Vaneev.
- HIIR: an oversampling and Hilbert
transform library by Laurent de
Soras.
- vectorclass: a library for
using SIMD instructions to improve performance on modern microprocessors by Agner Fog.
- PFFFT: a pretty fast FFT, by
Julien Pommier, with updates by Hayati Ayguen and by me.
- Boost
VST is a registered trademark of Steinberg Media Technologies GmbH.
Last release: version 1.2.
