Tips & Tricks: Improving Performance with Simplified Reps

Detailed drawings, colorful exploded views, and intricate cutaways wow customers and managers. But for engineers, all that detail takes forever to load and creates annoying lag when you try to work with your CAD model.

“Engineers don’t always need all that level of detail,” says Steven LaPha, a CAD and PLM administrator contracting at NASA. “They just need enough to get the job done.”

That’s why many PTC Creo users who work with large assemblies turn to simplified reps. A simplified rep strips out detail from your master model, freeing up CPU and memory. And while these versions of complex models are quick and easy to create, there are numerous options for creating them.

How detailed do you want that model?

In a recent presentation, LaPha describes many of the different ways you can approach simplified reps. In fact, he proposes a system that breaks down simplified models into 10 distinct weights (see slide below).


Various levels of simplification

He then demonstrates how to create some of those simplified models, specifically, default and manual envelopes.


In this example of a simplified model, LaPha excludes all hardware and parts under a specified size.

If you’ve never simplified your model before, or if you suspect you aren’t using the capability to its fullest, LaPha’s presentation Bringing Large Assemblies Down to Size is worth your time. (Ed. Don’t be misled! Despite the presentation’s title, he’s not actually changing the assembly size as he simplifies the data.)

You’ll need to register to access the presentation, but once you have a login, you’ll have access to many more customer presentations packed with tips from some of the most experienced PTC Creo users out there.

Create a simplified rep using rules

If you want to further explore some possibilities, try defining a simplified rep by creating a set of rules to specify what the system will and won’t load when you open a model. (Note. Our experts warn that rules can sometimes slow retrieval, so weight the benefits and drawbacks for your own situation.)

To create a set of rules, follow these steps:

1. With an assembly loaded, open the View Manager
2. Click Simp Rep > New to create a new set of rules. Then type a name for the new rule set.


Using the View Manager dialog, you can either create a new set of simplified rep rules or edit an existing set of rules.

3. In the Edit dialog, in the Rule column, use the down arrow to change the rule for the main assembly to Graphics Rep.


Specify parts that should be excluded from your simplified rep using the Edit dialog.

4. Using the RULE column’s drop-down arrows (shown above), further manually select the parts you want to include or exclude from the representation and then click OK, or try the steps below to create automated rules.

  • From the Model Rules drop-down menu, click Edit Rules. The RULE dialog opens (as shown below), allowing you to set up new rules for your simplified rep.
  • Click the + button to add a new rule. Then, right-click the new rule’s Condition, select New, and type a name for the new condition.

On the RULE dialog, right-click a new rule’s Condition to edit the rule’s attributes.

  • Set rule attributes on the Rule Editor dialog, which is shown below. Click Add New after you specify attributes that will be part of the rule. A list of rule attributes appears in the Query Builder
  • When you are done editing the rule, click OK.

Using this dialog you can set conditions for what parts of your assembly will be included and excluded in the simplified rep.

To watch a demonstration on setting up simplified reps using rules in PTC Creo, register for a (free) PTC University Learning Exchange login and check out this video.

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