All the parts are grounded in the main assembly. The game allows for the field to be changed, so remove the grounded status from any structures and then move to a new location adding constraints or grounding as required.
STEP
The parts will not be grounded when you open the file. When I open a STEP file I ground the parts to get started.
Please let me know if the download works OK. I have tested it and worked for me.
When converting either file to solidworks, it either completely breaks or creates spheres where objects are supposed to be. Can someone convert to solidworks and post a download?
For what it’s worth, the Inventor format listed is the 2016 version of Inventor, which isn’t backwards compatible with 2015. 2015 is what we have on our school computers.
The STEP import is working fine for me, and even comes through with proper color. So I’ll work to upload the 2015 Inventor version of the field to my GrabCAD tonight, then publish it so it’s available at our team CAD library link in my signature.
Edit - turns out the upload was pretty quick - Direct Link
I opened the STEP file in SW 2015-16 Student Edition. Some minor face and gap errors, but I think all the critical parts are OK. I put the SW files on GrabCAD. I renamed the game specific assemblies from their drawing numbers to their names in the Game Manual so that they are easier to identify in the feature manager. I also created a new assembly of the tower and batter.