Hi,
Some of us are fascinated by optics and want to understand more how they do their magic. However, commercial software such as Zemax is very expensive. Unless one is a optical designer by profession the cost cannot be justified.
Fortunately there are a number of OpenSource (free) solutions available. This thread aims to list useful software and where available, user comments and reviews of the software.
Ray-Optics by Michael J Hayford
This is one of the best OpenSource optics software available at the moment. Its focus is on geometric ray tracing and analysis. It is written in Python and can be used in Jupyter Notebooks.
ray-optics.readthedocs.io/en/latest/index.html
The author used to professionally work in designing optics software.
A number of examples using this software is available at github.com/mjhoptics/ray-optics-notebooks/ .
The project is maintained at github.com/mjhoptics/ray-optics
Geopter By Hiiragi
This software started out as a C++ port of MJH Ray-Optics but now has additional capabilities of its own.
github.com/heterophyllus/Geopter
I have not yet personally tried this but it looks very promising.
Beam4 by Stellar Software / Michael Lampton
This software is written in Java, and is now also available as OpenSource at github.com/StellarSoftwareBerkeley/BeamFour .
The author has retired and so this software is unfortunately no longer maintained by the author.
For an overview of this software watch youtu.be/-buXsCqEnq8.
This software is slightly difficult to use, as it expects inputs as text spreadsheet like files.
Moreover user needs to specify all the rays he/she wishes to trace.
The tracing is three-dimensional, and the software can depict the model in 3D (within a 2D viewer).
GOptical - GNU Optical design and simulation library by Alexandre Becoulet.
GOptical is a ray-tracing optics software written in C++.
www.gnu.org/software/goptical/
The original software has not been maintained since 2012.
I tried to modernize it a bit here github.com/dibyendumajumdar/goptical .
While the ray tracing functionality works fine, most of the analyses performed are incorrect as the software does not know how to find the chief ray.