Center of Mass Issue

I just made a model of a spaceship and for some reason after I joined the various parts into a single mesh the center of mass vanished from the screen. I can still set center to cursor and place it inside the ship, but if I choose center of mass it seems to go way off screen. At this point there is a dotted line from the model to the top of the screen, and the Rotate and Scale functions simply slide the model, but do not scale or rotate it (they work fine if I put cursor in model and set center to cursor).

Anyway the problem is when I export the model and import it into Netfabb the model doesn’t appear, though I see a green square which I believe is the center of mass. I believe that somehow Blender has gotten confused and set the center of the object way off the 0,0,0 point of the grid, and I don’t know how to find it or reset the model with the proper center of mass. I have attached the blend file and would appreciate any help in resolving this issue! I’m sure it’s a simple problem but haven’t run into it before…

ThanksSaar Carrier.blend (1.76 MB)

Are you using the latest version of blender (2.69). If not, do so and you problem should be fixed

It is 2.69. One thing I noticed is that when I ran the file through it says the mesh couldn’t be analyzed because it is greater than 5 meters in size. However, it measures on the grid as about 6 cm long. So I put it in Bounding Box view mode and it seems for some reason the bounding box is 3cm X 140cm X some immeasurable amount (download the file from the initial post if you’d like to see). But the model itself is only 60mm at the longest (60 Blender Units, assigning the standard cube at 2 X 2 X 2 BU). So for some reason Blender is reading the object boundary as ridiculously larger than the visible model.

You have some loose vertices+polygons that are way out there somewhere.

Go into edit mode, lasso or box select only the ship itself, press P to separate it to a new object.
Delete the old object.