BRL-CAD is a powerful constructive solid geometry solid modeling system that includes an interactive geometry editor, ray-tracing support for rendering and geometric analysis, path-tracing for realistic image synthesis, network distributed framebuffer support, and image and signal-processing tools.
QCad is a powerful but easy to use 2D CAD program for Linux, Windows, and Mac OS X. It uses DXF as its standard file format. While other CAD packages are often rather complicated to use, QCad tries to stay comfortable, and even an absolute beginner can create professional drawings with a minimum of effort.
LinPHA is an easy-to-use, multilingual, flexible photo/image archive/album/gallery written in PHP. It uses an SQL database (MySQL/PostgreSQL/SQLite) to store information about your pictures. It comes with an HTML-based installer, so you don't need experience in setting up SQL databases. Thumbnails are created as needed and stored in the SQL DB. It features complete user management, top ten statistics, hidden albums, different themes, slideshow, filemanager, uploader, watermarks, benchmark, printing, and more.
PDFreactor is a formatting processor to convert HTML and XML to PDF. It uses Cascading Style Sheets (CSS) to define page layout and styles. It allows you to dynamically generate PDF documents such as invoices, delivery notes, shipping documents, or print versions of Web content on-the-fly. Vector graphics (SVG), barcodes, MathML, XSLT, and CMYK colors are supported. All common J2EE application servers are supported. Complete .NET, PHP, Perl, Python, and Ruby APIs are included. Direct integration into automatic build processes using Apache Ant is also possible.