AudiLab Thrup’ny: The 3d 3-D viewer Threepenny coin

Thrup'ny screenshot

Usage : Features : Download : Internals : Related

Thrup’ny is a free, open-source multi-platform viewer for VRML 3-D models, designed for both anatomy teaching and finite-element pre- and post-processing.


Quick start: Use File ▶ Open to open a local VRML .wrl file, then click and drag to manipulate the model. Use the Esc key to switch between the viewing and pointing modes.

To view VRML models with a Web browser, configure your browser to use Thrup’ny as a helper application for .wrl files.


In the list above, the underlined characters are accelerator keys, invoked initially using the alt key. The square brackets [] indicate shortcut keys, with ^ denoting a control key, that is, holding down the Control key while pressing the indicated key. Note that the shortcut keys involve pairs of keys in some cases, such as Ctrl-C followed by P to invoke a perspective camera.

Viewing and pointing

The Esc (Escape) key can be used to toggle between the viewing mode and the pointing mode:

Locations and viewpoints

The toolbar contains two dropdown lists, one for locations (URL’s) and one for viewpoints. For each, a check-mark button can be used to invoke the currently displayed item.

To invoke a URL, select it from the Location drop-down list so it is displayed in the box, or type a new one into the box, and then press the check-mark button (or press the Return key).

The Viewpoints list displays the names of any viewpoints that are predefined in the model definition. A viewpoint can be invoked by highlighting it in the drop-down list. To return to the last-selected viewpoint (the name of which is currently displayed in the Viewpoints box) click on the check-mark button.


Features and Plans

Thrup’ny will

The items in the list above have been implemented or partially implemented, or have not yet been implemented.

Download and installation

Thrup’ny is licensed under the GNU General Public Licence. GPL implies that the source code is available, but it is not linked to on this page – contact me if you want it. If I am not properly complying with the GPL, please let me know.

If you are running Linux in VirtualBox under MS Windows as the host operating system, you may get better performance by running the Windows version of Thrup’ny rather than the Linux version.

Microsoft Windows

Thrup’ny for Windows consists of an executable file, thrupny.exe, and several DLL files. Below are downloads of the files in three alternative forms.

Once you have all of the files in a single directory (e.g., C:\Program Files\Thrupny\), double-click on thrupny.exe to run it. Create a shortcut in the Start menu or elsewhere if you wish.

If Thrup’ny fails with a message saying that OpenGL doesn’t work, it may be trying to use a less-powerful integrated graphics processor rather than a more-powerful specialized one. Try right-clicking on thrupny.exe and look for Run with graphics processor in the menu that pops up. It may provide a choice of processors and indicate which one is used by default. It may also provide an option to Change default graphics processor. If there is a choice, try running Thrup’ny with a graphics processor other than the default one. If that works, consider changing the default, either globally or just for Thrup’ny.

Self-extracting executable

Download one of these files into some folder and then double-click on it. It will extract the Thrup’ny executable and the DLL’s into the folder that it’s in or into a folder that you specify.

Zip file

Download this .zip file and use an Unzip utility to extract thrupny.exe and the DLL’s into some folder.

Individual files

Download all of the following files into the same directory. The DLL files are local copies of required third-party libraries, for convenience; they are all subject to the GPL or similar licences.

Once you have all of the DLL’s, you need only download thrupny.exe in order to upgrade it.


Download and extract its contents into some directory.

Alternatively, download thrupny, thrupny_run and each of the required lib* files (see below) to wherever you like, as long as they’re all in the same directory.

Use cd to get into the directory where you have stored the files and do chmod u+x thrupny* to make thrupny and thrupny_run executable. The latter is a script that causes thrupny to look in its own directory for its libraries.

To run Thrup’ny, use cd to get into the directory where you have stored the files and do

Required files:

Documentation of Internals

Names starting with Q are from QT, those starting with So are from Coin3D.

The C++ source files include:

Related resources

Thrup’ny is based on the free-and-open-source Coin3D (in particular, Coin and SoQt) and Qt. It is being developed under Debian GNU/Linux and MS Windows and should be portable to other operating systems.

Thrup’ny is based in part on code and advice generously provided by Sylvain Carette.

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R. Funnell
Last modified: 2021-07-15 11:33:57