Solid DNA blog

Blog about stuff on Solid Edge CAD software

Synchronous Control

Last post

Key phrase from the last post was:

“Allow more freedom to apply unpredicted changes”

…..and I left you with this question:

What kind of control do we have?

The main tool to work our way when it comes time to apply these unpredicted changes is the steering wheel. The steering wheel allows users to control the six degree of liberty around a surface.

Steering Wheel

This shows you the potential of the tool inside Synchronous Technology (ST). For those who are not familiar, it may be scary having all that flexibility. So we need to balance with rigidity to make sure the model  keeps its integrity.

To make a big picture there are two kinds of modification that could affect a part:

  • The morphology – a shape modification
  • The dimensional – a change of dimension (measurement)

So as you move the surface(s) of your model, the synchronous solver works in the background and checks your model with a set of tools:


  • Live rules
  • Driven dimension
  • Driving dimension
  • Equation
  • Procedural feature
  • 3D constraint (Geometric tolerance)


Live Rules

In my introduction to ST I talk about geometric tolerance (GT) to describe the type of constraint analyzed by Live Rules (LR).  Since many of us are used to this terminology I find it appropriate to use this image to represent the behavior of (LR).

LR is a set of GT that analyze the shape in order to found the correct behavior of the model.


Live rules

Once the move is launched and LR has started to recognize the GT specified by the user, faces will be collected and placed in a bucket to behave as a group.

Lives rules

Driven dimensions

Driven dimension can be placed at any time during the design. Users place them using Product Manufacturing Information (PMI) standard. This means they can be placed either on a 2D sketch or a 3D model.

Driven dimension are dimensions with two personalities.

  • They act as a reference
  • They act as a master dimension

This dual personality is useful when exploring different scenarios for a design, especially at the R&D stage.

Not happy to have two personalities they also have bidirectional behavior. What does this mean? User have the opportunity to decide which side of the dimension will receive the modification.

These driven dimensions provide one facet of the flexibility of the ST paradigm.

Driven dimension

Driving dimensions

As users explore scenarios some dimensions become more critical or take more importance, this is where the driving dimensions play their role.

Driving dimensions are the evolution of the driven dimensions in a way that we can only change them by keying value. They are not influenced by the surrounding environment.

They will be identified by a FUSHIA color.

To make a driven dimension become driving, simply lock the value.

Lock dimension


As scenarios get more complex and the parts started to acquire their own personality, the next evolution of the dimension found its way.

Equation helps to capture a more complex behavior where “Variable Rule Editor” interacts with formulas. The conditional form can be used to better refine the intention of the designer.

The process of creating an equation is the same as what we were doing in pre-ST.



Procedural Feature

A procedural feature is a collection of faces that contains a predefined bahavior.

Rectangular/circular patterns, holes are among the most common, those are the closest to traditional feature modeling. Users simply select the procedural feature and edit the input without having to go back in time.

As an example any instance of a pattern represents the original feature, allowing each of them to modify the original feature.

Procedural feature

3D Constraint

As the dimensional personality of the part gets more defined, in parallel the morphology of the part gets shape using GT. Both influence themselves in a bilateral way to define the personality of the part.

Since the beginning I haves the term GT to better illustrate the concept of 3D constraint.  At the top of the article we saw that LR solves those GT automatically based on the user input.

Two situations could exist:

  • User does not want LR to solve the GT
  • User needs to create he’s on set of GT

To suspend the LR simply check the “Suspend Live Rules” option at the top. Once the LR are suspended the integrity of the model can be compromised.

To establish new rules for topology solving without using LR, we use the “relate” command found on the floating toolbar when a surface is selected.


Once the relate option is active, SEwST offers a set of GT to the user.


Once the proper relation is established, the user has two choices:

  1. Apply the relation (green check), next time LR is enabled it should recognize it and automatically solve it.
  2. Apply a persistent relation by activating the lock on the floating toolbar prior to clicking the green check.

Once the persistent option is activated, the proper relations are place in a bucket at the bottom of the Edgebar.

 3D constrain

You have mastered the steering wheel, you’ve become an A’s when it comes to dimension and apply logic on the model,  you’re one of the kind artists when it comes time to shape your project…….

Part  is born and get its own P/N. As a parent you will take care of him, educate him, and she/he will grow and develop its own personality, its own behavior.

Will she/he become a lazy standard part or become an Olympic athlete?

But before they go in production they must pass thru……

The teenage phase where all parents are afraid to lose control, this is where each case needs a personal touch.

Personal touches are also used when it comes time to  face a career change, at retirement when chirurgical intervention is needed etc…..

 See you…… my next post for Synchronous personal touch.

For fun

P.S. For those designers who are afraid of becoming bad parents contact you’re nearest reseller for “Synchronous Parent 101”

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