FreeCAD - An open-source parametric 3D modeler
Netbeans - NetBeans IDE 7.0. Develop desktop, mobile and web applications with Java, PHP, C/C++ and more. Runs on Windows, Linux, Mac OS X and Solaris. NetBeans IDE is open-source and free.
SketchUp - 3D for Everyone
Eclipse - Eclipse is an open source community, whose projects are focused on building an open development platform comprised of extensible frameworks, tools and runtimes for building, deploying and managing software across the lifecycle.
LibreCAD - An open source 2D CAD application for Windows, Apple and Linux.
IntelliJ IDEA - Capable and Ergonomic IDE for JVM