There are a couple of approaches to this. The first approach would use a
program to query the part for its size and write this information as
properties. This could be a simple macro that only does this when it's
executed or a more elaborate add-in that's monitoring the part watching for
changes and automatically updating the property values to reflect the
current size. One big issue with this approach is determing the actual size
of the part. The obvious thing to do is to use the range box of the part.
This is a rectangular box that entirely encloses the part. You can easily
get this box and its size using the API. The problem is that depending on
the orientation of the part the range box may not be what you want. The
range box is always oriented such that it's parallel to the prmiary x,y,z
planes of the part. For parts that aren't oriented with respect to these
primary planes, the range box will typically report a larger size than you
expect. You might also have a logical length and the direction will vary
depending on how the part was modeled. For example in one part the length
might be along the x axis whereas in another part it might be along the y
axis.
Another approach is to have parameters in the part that represent the
length, width, and thickness of the part. These can be parameters that are
driving the part or can be reference parameters that you created after the
part was built. In the parameters dialog there is a check box for each
parameter where if you check that value it will automatically export it as a
property.
--
Brian Ekins
Autodesk Inventor API