Part VI: Using Advanced Techniques
Using Powerful Tools Responsibly
I find myself giving the same responsible-modeling advice when discussing multi-bodies as I tend
to give for in-context modeling and virtual components. This is because multi-bodies present some
of the same issues as in-context modeling. The first similarity is that on the surface, both techniques
appear to be all-day-every-day types of design tools. The second similarity is that there is more to
the story than what initially appears.The responsibility part arises when you are thinking about the users who will use the multi-body
parts once they are created, including yourself. It is not always easy to remember how you executed a
particular project 6 months and 100 models ago. Other users may have to edit your work, and if
errors happen, then you have to be able to navigate the design intent without destroying the
relationships in the FeatureManager or completely rebuilding it. This is the reason for trying to
standardize best-practice issues, particularly with advanced functionality and particularly in larger
organizations where more users may work with the data.If you are an independent contractor and do not share your models with other SolidWorks users,
then you have more flexibility to model how you like. As long as you can come back to the model
and change it when you need to, more power to you.Comparing multi-body modeling
with assembly modeling
This concept is important, and so I will repeat it: Multi-body modeling is not assembly modeling.
Many times when new users are introduced to the capabilities of multi-body modeling, the first
thought that comes to mind is, “This is far easier than making assemblies.” However, multi-body
modeling should not be treated as a replacement for assembly modeling.Several assembly type functions are missing or more difficult to obtain from multi-bodies. They
include the following:l (^) Interference detection
l Dynamic assembly motion
l (^) Exploded views
l Configs for separate parts
l (^) Drawings for individual parts
l Center-of-gravity calculations for individual parts
l (^) Mass property calculations for individual parts
To say that these functions are missing from or difficult in multi-bodies does not imply that they
should or will be there someday. In fact, I believe that the distinction between multi-body and
assembly modeling techniques should be kept as clear as possible. Simply because a technique is
easier does not make it better. Above all, remember that modeling multi-body parts puts all the data
for all the bodies in a single part file, in a single FeatureManager; there is no easy way to separate out
the parametric features into individual parts later on, regardless of how complex the part becomes.