The context is the problem of the quality of UAP observation reports.

A written description is ambiguous. A picture is worth a thousand words. A 3D animation can fully describe the visual and spatio-temporal aspects of an observation.
By simulating physics (even very simplified) or ensuring at least some internal consistency in the trajectories, the simulation can help test/reject hypotheses.

Obtain better and more elaborate estimates of the observation parameters.

• The availability in 2021, on the consumer market of standalone (untethered) Head Mounted Displays (HMDs) for Virtual Reality (VR) and Augmented Reality (AR). These new HMDs do not even need to work in a fully controlled environment. They don't need “reference bases” or pattern targets to be placed around.
• The availability of free frameworks for the development of applications targeted on these devices. Namely : Unity 3d.
• all the reasons that motivated the invention of the SIMOVNI.

Some of the issues with SIMOVNI are solved, some appear. Many new things can be done that were impossible.

Solved with some HMDs

• unobstructed view solves the issue of the under estimation of angular sizes when looking through an opening (eyepiece of a refractor or binoculars for example)

The new or remaining issues with HMDs are developed below.

We expect better and more elaborate parameters estimations with such a tool than with the basic methods used by the investigators.

KISS (Keep It Simple Stupid) and remain pragmatic.

One of our goals in this development, is to over specify and explore the theoretical/practical potential of the technology, yet limit ourselves to the most simple developments and proceed progressively and evolve the software based on the field results.
We thus also define a minimum implementation.

Before doing anything, we need to be sure we can obtain something of interest (see limitations).

Exploring the Limitations of Environment Lighting on Optical See-Through Head-Mounted Displays. Study on Hololens 1 & 2. pdf where it can be seen, on figure 3 (b) that the visor has a transmittance of about 30%. That figure is the one of interest for our measurements of the brightness of the display.

Le problème de la taille apparente de la lune selon Camille Flammarion : COMMENT VOYEZ VOUS LA LUNE GROSSE ? LA NATURE, N° 29, 20 décembre 1873, page 38 à 40 en copie sur le site web de Dominique Caudron. http://oncle-dom.fr/paranormal/ovni/ufologie/temoins/taille_lune.htm

On “The power of methods guided by recognition rather than description in the reconstruction of a fleeting event” http://www.project1947.com/shg/symposium/shepard.html & https://rr0.org/time/1/9/6/8/07/29/Symposium/Shepard/ To be interpreted with caution.

Inforespace Bulletin n°2 aout 1985, 13eme année, page 8. Fiabilité de l'estimation des dimensions (angulaire de la lune et du soleil)
relate une étude statistique réalisée par un groupement Allemand sur 238 personnes.
Dont la dernière version date de 2009 et est ici : JUFOF 183

Pierre Lagrange : “A propos des prétendus aspects psychologiques et sociologiques des témoignages d’observation d’ovnis”. Annexe consacrée à l'historique du SIMOVNI. https://www.cnes-geipan.fr/sites/default/files/29_LAGRANGE_full.pdf
Pierre Lagrange fait référence à la fin à Inforespace de Décembre 1978, mais je pense qu'il fait référence au Inforespace Hors Série #3 de Décembre 1979 avec l'article (à charge lourde) de Dominique Caudron p14-p38.

Voir aussi

• http://rr0.org/people/c/CaudronDominique/#/SimOVNI
• http://rr0.org/people/v/VelascoJeanJacques/

The paper trail shows Dominique Caudron was the first in France to build a practical device around 1974.