I would like to make a list of remarkable robot simulation environments including advantages and disadvantages of them. Some examples I know of are Webots and Player/Stage.
This made me remember the breve project.
breve is a free, open-source software package which makes it easy to build 3D simulations of multi-agent systems and artificial life.
There is also a wikipage listing Robotics simulators
It's not as impressive looking as Webots, but RobotBasic is free, easy to learn, and useful for prototyping simple robot movement algorithms. You can also program a BasicStamp from the IDE.
Microsoft Robotics Studio/Microsoft Robotics Developer Studio 2008
Also read this article on MSDN Magazine
ABB has a quite a solution called RobotStudio for simulating their huge industrial robots. I don't think it's free and I don't guess you'll get much fun out of it but it's quite impressive. Here's a page about it
I have been working with Carmen http://carmen.sourceforge.net/ and find it useful.
One of the disadvantages with Carmen is the documentation with all respect I think the webpage is a bit outdated and insufficient. So I like to hear from other people with experience in working with Carmen, or student reports/projects dealing with Carmen.
ROS will visualize your robot and any data you've recorded from it.
Packages to check out would rviz
and nav_view
National Instruments' LabView is a graphical programming environment for developing measurement, test, and control systems. It could be used for 3D control simulation with SolidWorks.
I've been programming against SimSpark. It's the open-source simulation engine behind the RoboCup 3D Simulated Soccer League.
It's extensible for different simulations. You can plug in your own sensors, actuators and models using C++, Ruby and/or RSG (Ruby Scene Graph) files.