Last Updated: February 8, 2018
CCycloid is a program to generate graphs of Curtate Cycloids, which are the curves produced by a point within a wheel, when that wheel is rotated. The intended users of ccyclid are makers of stringed instruments, but the program is available for anyone to use. CCycloid creates the graphs in PDF, PostScript, or DXF format.

For more information on cycloids, see one of the following web sites, which are just a few among many to describe cycloids:

Browser Version

Browser Version This is the latest version and should run in any web browser. Just click the link above.


Below are older versions of the program that required downloading and installing some software. They are unsupported now. However, they will may still run on modern Windows machines.

Vista Version

Download and unzip it. You will want to place the folder 'VistaCycloid' on your Desktop. To run the program, open the folder 'VistaCycloid' and double click 'cycloid'.

Old XP Version

This version may dissappear since the Vista version works on XP machines.

You should create a folder in which to put the cycloid program. You should then download the following three files to this folder:

Note: This program has been tested on and runs on Windows XP and Windows ME. If you can or can not run it on another OS, let me know and I will update the information here. It did NOT run on Vista.

The previous version of this program (which does not require MSVCRTD.DLL) is available here.

There is also a Mac version available.

To read PDF files, you will need a copy of Adobe acroread. ACROBAT READER

Changes in version 3.4.3

Changes in version 3.4.2

Changes in version 3.4.1

Changes in version 3.4

Changes in version 3.1

Changes in version 3.0

User Interface Overview

Here is an image of the user interface to ccycloid on the left, with a sample of the output on the right:

cycloid UI cycloid example
Create the curve Quit cycloid Use millimeters Use inches Set the width of the cycloid Set the height of the cycloid Plot a cycloid curve Plot a catenary curve Read a CSV file Check to have file name automatically created Name of file where cycloid will be saved Title to put above curve Scale height Scale width Status messages appear here Percent of full cycloid to use Check here to print caption (e.g., W=80.00, h=8.00) Check here to enable/disable auto-redraw Curve preview Check here for PDF output Check here for PostScript output Check here for DXF output Check here for CSV output Check here for Letter size paper Check here for Legal paper Check here for A4 paper Check here for A3 paper

Typical use of the program would be to set the width and height, and click "Create Curve" to create a PDF file for the graph of the cycloid. In the case of cross archings of the violin family, it should be remembered that these curves

  1. need not originate at the edge of the plate. Many makers place the lowest point well inside the purfling.
  2. indicate the outside shape, and so the thickness of the wood at the lowest point should be subtracted from the total height of the arch when calculating the dimensions of the graph.
Note that as you change the width, height, and percent, the curve in the curve preview region will change. The curve drawn here is meant as a rough preview for shape, and is automatically redrawn to be of maximal size within the curve preview region. If your machine is slow, unselect the Redraw check box to disable updates.

What follows is a description of the entire user interface:

Hints on Printing

Depending on your printer, etc., you may need to select the print options "Landscape" and "Print as Image". Do not select "fit to page".


ccycloid was written by Stephen Mann for Quentin Playfair, with some help porting to Windows by Gilad Israeli. The catenary curves were added at the request of Tom King. The user interface was written with fltk. This program is completely unsuported, although suggestions for changes will be considered. A linux version is also available on request.