Instruction: Extract information from the supporting document to answer the given question.

Input:
Question: Is this a mouse where you move the whole thing to navigate or more like a trackball where the whole thing is stationary and you just move part?
Document: Bought a copy of Solidworks recently and read that this would make working easier. They weren't kidding. This is the best thing I've used since I was introduced to the mouse many (many...many) years ago.I mouse with my left hand though I'm right hand dominant, so I work with the SpaceNavigator in my right hand and I find it completely natural to move and rotate the part while I use the mouse to click on edges, etc.
This is a great product, it works really well with all 3d software and some none 3d software.. The only thing I didn't like is the auto center feature in solidworks.. It's annoying when you want to focus on some part and your center axis is fixed to another part.
It took me about 15 minutes to get the hang of moving it around, but once I did, it was like flying a camera through the scene. It cut my time to pose a model down to a few minutes versus a couple of hours because you're constantly having to go to the left panel, move the camera, try to get a good view of the body part or prop, then turn back to the pose controls. The Spacenavigator really did away with all those headaches.
The MAIN role of this is for use in 3D application. Virtually every CAD program today has full support for this (or other similar devices - and there are a few out there from other suppliers). You can move a CAD "part" or "assembly" just by holding the "puck" in your hand and applying rotational or translational pressure on the device.A significant number of 3D rendering packages also have full support for this... programs like Lightwave, Maya, 3DStudioMax, and so forth.
I credit this to changing my keyboard, controller, and mouse regularly, their type and location on my desk. This is my third 3D controller, part of my repetitive motion avoidance plan, and the best one yet. You will get the cost of this thing back, in time saved, the first week.
You can even control the rate of motion. After using it for a day in a 3D environment it's almost like thinking and you see the motion happen in front of you.For SecondLife users, you can move your avatar naturally. None of that "bumping into doorways" thing. Click the side button and you start moving the in-world camera like you've got it in the nose of a helicopter.
I saw some videos and loved the idea of navigate in 3D spaces, and it is exactly of what this mouse is capable to proportionate.The 3D design become more natural, and Google Earth experience just amazing. I am not a gamer, but I thing a gamer would love that mouse as well!! !
But, even for animations, the SpaceNavigator lets you quickly set up camera positions.Google Earth is pretty fun with it, too - again, completely fluid navigation, vs the move, pause, jerk kind of navigation achieved with a mouse.Note that this review is on the SE page, but applies to the PE model as well. The license is the only thing I hate about this thing. The SE and PE models are identical, differing only in their license details.
This isthe reason I still use vi (unix text editor). Not having yourhands leave the keyboard to use a mouse saves half a sec x 1000 timesa day. Same thing with this. With revit, the 2 times I'dneed to hit the kb would be for esc and tab or space, so you couldprogram the buttons if you wanted.So much of the time, you grab an object, and then want tograb the end to resize or move. Oops, the end is off the screen.
The SpaceNavigator 3D Mouse is an excellent product. After I learned to use the 3D mouse, I found I was working twice as fast. Using the 3D mouse allows me to navigate with one hand, while using the other to access a tool. That's like combining two steps into one. This is one of the smartest purchases I ever made, and I'm happy to report that all my major programs...Modo, Poser, Photoshop...all support the SpaceNavigator.
Answer: The base is stationary.  This is not work as a mouse.  The upper portion works with very little motion, more on pressure.  It is heavy enough that it does not move around.  I use it for viewing graphics used for writing Machining code.  It will probably work with most graphics programs to rotate the 3D graphic.  I am very happy with it.