Chapter 16: Modeling in Context ...............................................................................................
Major potential problems include:l Lost references due to renamed assembliesl (^) Convoluted references causing long rebuild times
l Circular references causing changes with each rebuild
l (^) Frustrated users who don’t understand how to manage change in an in-context scheme
However, you can overcome these difficulties. In the rest of this chapter, I show you how to make
the most of in-context modeling.
Identifying alternatives to in-context modeling
The kinds of problems users typically have with in-context modeling are related to file manage-
ment. Inexperienced users may rename a file and break links, or try to use an in-context part in
some location other than where the in-context relation was created, and may not be able to make
changes that they want to make, or changes happen when they do not want them to.
Sometimes these problems are the result of the user simply not understanding what to expect from
the tool, and sometimes it is because the tool is not capable of what they are trying to achieve.
Right or wrong, many users have developed an irrational fear of references that can control a part
from outside of the part itself. In-context modeling in itself is not a bad technique, but sometimes
it is not the best option. I recommend thoroughly understanding in-context and all related tech-
niques before passing judgment on any of the techniques.
It’s always important to identify alternative techniques because one tool never solves all possible
problems. In-context modeling is powerful, but in some situations other techniques are better
suited. In this case I want to introduce you to a couple of techniques that share with in-context the
ability to control individual parts from a centralized location, but achieve that in ways that are
somewhat different: Assembly layout modeling enables you to control individual parts not from
other parts, but from an assembly level sketch. Multi-body modeling enables you to control several
parts from a single part without worrying about the file management issues of having another
assembly as the middle agent.
Assembly layout modeling
Assembly layouts are powerful tools that remove much of what some people object to in in-context
modeling. Relationships in this technique are controlled by top-level sketches, where a single or
multiple sketches can control most of the features on all parts through relationships between part
sketches or features and the assembly sketch. This still creates an external reference that requires
the existence of an assembly to update the relationships, but it is not a direct link between different
parts in the context of the assembly.
Assembly layouts do not lend themselves well to dynamic assembly motion, but they are great for
having a single location to drive an entire assembly. Assembly layouts come in two flavors, the
generic layout which is simply done using sketches in an assembly; and the formal Layout feature,