from Civil to Inventor

The Autodesk enthusiast exile

Inventor – Assembly Constraint Naming

Management of features and components in Inventor is kind interesting.  In AutoCAD, the technician is free to create things in almost any way.  A great deal of management is required to be efficient.  I recall using Inventor for the first time.  It was such a relief, because Inventor automatically took care of entity management through styles.  Features however are a different story.

Naming features such as constraints is one option available to help reduce the confusion in Inventor.  If you don’t rename constraints, you can end up with spaghetti.  Waiting until you have a troubleshooting session to rename the Assembly Constraints will result in a disaster, because you will have numerous Constraints all named similarly.

Design Accelerators compound the issue because they autonomously create features at once, without consulting the user for names.  When you get done with a few gears, you have a mess.


In this example I was troubleshooting why my actuator was not moving in the assembly when the motor motion was applied.  When sorting constraints out, I recommend 3 things:

Changing to Modeling View


Changing the view will group all the constraints into 1 region, assembled into 1 feature instead of broken into pairs over the 2 respective constrained components.  This allows us to see them in a simple collection.

Rename the Assembly Constraints

Renaming the Constraints as you go is quite important.  After creating 2 sets of gears and a shaft, I have about 18 constraints named Angle:2 and Mate:5.

So I like to give them names that include:  The 2 components that are being constrained; The purpose of the constraint; possibly the nature of the constraint as well.

In this example I had an overlapping constraint, but could not see it until I had changed to Modeling view and finished renaming everything.  I pick each object, and Inventor highlights the planar faces and features that are associated in the Constraint, which allows the user to get a feel for what is going on.


I renamed this angular constraint to WormToSpurGearLock, so I would see the 2 Gears involved (Worm and Spur gears), and the purpose was to lock their rotations together.  In another I used MotorShaft-Drive so that I could find the Drive components quickly and distinguish them from the others.


If I wasn’t sure what was constrained, which is often the issue, we can Isolate the pair.  This way it is quite easy to see how and what is being constrained.




Once the naming was complete, it did not take long to read each one, and check off the list of what was expected between each component. Eventually I found where I had included an angle control on the shaft that would not allow the actuator to turn.

Naming your Constraints as you complete procedures, whether it be manual assembly, or Design Accelerators is a good habit to get into.  In his example I just needed to proof out a solution, but inevitably wanted to keep it.  Taking the small amount of time to name the constraints as you go will really pay off in the future.

January 4, 2010 Posted by | 2010, Constraints, Gear Generator, Inventor | , , , , | 2 Comments