SolidWorks 2010 Bible

Chapter 16: Modeling in Context

Best Practice
For best practice, you should use either the SolidWorks Save As command or SolidWorks Explorer to rename
parts and assemblies. This applies to all parts and assemblies, but doubly to in-context documents. n

In-context and mates

I mentioned this earlier, but a section on in-context best practices would not be complete without

issuing the warning against mating to in-context features. Mating parts to in-context features cre-

ates a parametric daisy chain, thus establishing an order in which assembly features and mates

must be solved. This always creates performance problems in assemblies, especially large ones. The

SolidWorks AssemblyXpert looks for this condition when examining assemblies.

Circular references

Circular references in assemblies are a bigger problem than most people realize. In fact, most peo-

ple do not realize that circular references are a problem, or, for that matter, that they even exist.

A circular reference takes the form of “Part A references Part B, which references Part A.” It creates

a circular loop that really wrecks assembly rebuild times. Part feature design trees are not suscepti-

ble to this sort of looping because the part FeatureManager operates in a linear fashion (at least

when it comes to applying relations between sketches or features).

The Assembly FeatureManager is solved in this order, or an order that is very similar:

1. Solve reference geometry and sketches that are listed before parts in order, at the
   top of the design tree.


2. Rebuild individual parts as necessary.


3. Solve the mates and locate the parts.


4. Solve in-context features in parts.


5. Solve reference geometry and sketches listed after the mates.


6. Solve assembly features and component patterns.


7. Loop to Step 3 to solve mates that are connected to anything that was solved after
   the first round on the mates.


8. Continue to loop until complete.

As you can see, even if you do not have a reference such as “Part A references Part B, which refer-

ences Part A,” it is still possible to get a highly convoluted, if not entirely circular, loop. Many users

with smaller assemblies in the hundreds of parts complain about very poor performance.

Skeletons and layouts

When you are making in-context references, a technique that can help you avoid circular refer-

ences is to always create references to parts that are higher in the design tree. You can expand on

this idea until a single entity is at the top of the design tree, to which all in-context references are