I have been interested in 3D since the 1980s. This page illustrates some of the works I have done, but is in no way meant to be exhaustive. I have been conducting many experiments, most of which have never been published. Some of them might be published some day.

Here are some noteworthy results:

• In 2020, I have spent about 500 hours constructing a 3D model for the destroyed clock at the Paris Notre Dame cathedral. (see the timeline of the application of 3D to clocks)

  This model was based on a few measurements I took in 2016 when I was lucky to examine the clock (something no one else seems to have done, not even clockmakers), as well as photographs. There was a very long, complex, and in particular computational process, and making this model was obviously much more difficult than merely measuring parts and transcribing them in some CAD software.

  As far as I know, this is the first time that a tower clock has been modelled that way. All known 3D models of tower clocks, for instance in the Chronospédia project, have been based on either direct measurements of parts, or measurements on 3D scans. These approaches are very low level and of course not sustainable.

• The 3D model of the Paris Notre Dame clock was put online in 2020 in several open formats, including STEP files. Noteworthy is the fact that the various parts of the clock have been made available separately, and in such a way that they can be reassembled by any decent software. This was the first time, to my knowledge, that such a model has been made available in such formats. This is still not done today (2025) by other projects such as the Chronospédia project.
• In 2021, I have made some animations based on my 3D model, and in particular animations showing the remontoire. This was, to my knowledge, the first time that such a remontoire had been animated. The entire animation is computed, without using ``physical dynamics'' which makes it possible for some CAD users to easily obtain such animations.
• In 2021, I also made an Android application (see apkcombo, apkpure, steprimo, or apkgk) which enables the exploration of the 3D model, as well as the selection of parts, the display of metadata (gear counts), and the animation of the going work. As far as I know, this had never been made before, and is also still not done by the Chronospédia project, at least as of 2025.
• Still in 2021, I had a group of students work on a 1/3 scale model of the clock.
• In 2022, I made some experiments of Augmented Reality with a Microsoft Hololens headset.
• In January 2025, I have finally made a glTF version of my 3D model of the clock, which makes it possible to explore the clock interactively and on any platform. This viewer goes beyond those provided (in 2025) by the Chronospédia project in that it does for the first time provide interactive exploration, some animation (only a minimal motion as a proof of concept) and the display of metadata.

Denis Roegel.

Last change: 6 November 2025.