The Representations are a integral part of the Autodesk Inventor Design process. Most users employ View Representations, but what about Positional Representations. Are you still not using these awesome features?
What are Positional Representations?
It is their job to store temporary modifications to Constraints, Components, and Patterns. An example is a stator assembly can be driven out of a motor for inspection, or a component ungrounded temporarily. We can then save this change and activate it whenever we need, making inspection and presentations much easier to accomplish. I personally use them as a preparation for Simulation.
A few things to remember about Position Representations are:
- They can not be adjusted while the Representations are set to the default Master Position.
- These are simply storage containers for feature overrides
- They cannot be edited directly, but instead the pertinent feature overrides are edited
- Components, Features, and Constraints offer different overrides in context menus
I have run this Bracket component set through Stress Analysis, and am now heading to Simulation. When I get there I will manually apply the joints, and need some ease of visibility. This will provide inspection capabilities during the Simulation Joint procedure, and for revision inspections later.
I will demonstrate pushing the Left and Right (Green and Tan) Assemblies apart, and saving the Positional Representation as ‘SimPrep’. I’ll Drive the PresserFoot (Red) up as well. We’ll use this opportunity to review some of the other capabilities of Position Representations as well.
Create a new Representation
We have to operate from a User created Positional Representation. While the Representations are activated as Master, no overrides are possible. This fact makes the Positional Representations seem a bit odd at first. Remember, they are simply containers for modifications. You need to activate one, and make feature overrides.
Right Click on the Position Header and Select New. A new Representation will be added to the list.
Give it the name desired, here I use ‘SimPrep’.
Now that we have this container, we can add our Constraint Offsets.
Override the Constraints
Change the Model Browser view to Modeling view. This will make the task much easier, especially if you have hundreds of constraints. Find the Constraint you wish to change, and Right Click on it.
The resulting Context Menu will contain Override options. Each of these will override the constraint in a Positional Representation.
This will bring up a simple dialog that will permit us to change the offset dimension of the constraint, and store it in the current Positional Representation. Future activation of this Position will force an override of the Contraint’s Offset.
This will do pretty much what it says. Remove the stored Constraint override.
This will cause the Position to Suppress the Constraint.
This will activate the Representations Browser, and Highlight the override.
This will activate a dialog that contains all the options for any overrides that might be stored for the active position. This includes not only the Constraint tab, but also the Component and Pattern tabs as well.
One thing that should be noticed is that we can effect ANY of the Positional Representations from here. At the top there is a pulldown that contains the list of stored Positions. You can change the Position being edited by selecting a different one. I remember once I had a Turbine Hub that I needed to be seen in 3 positions. I created 3 positional representations, and used the Override dialog to alter the angular constraint by 15° for each Position, all from this one dialog.
The Pattern Tab contains options to override Angular and Circular Patterns.
The Component Tab contains override characteristics for Grounding, Positional Offset, and Flexibility.
Remember: In any case of adjustment, you are only able to affect the specific feature Override that you have previously selected. If you selected a particular constraint, then that is all you will have access to, but you can apply those changes over any of the saved positions.
The context menus for Components and Patterns reflect the options in the respective Override Dialog Tabs above.
Completing the Example
After identifying the 2 mate constraints that will be affected, I right click the Left-Right Mate and select Modify (Override)I changed the offset to 3”. I repeated the process for the Presser Foot, and changed its offset to 1.5”.
The Overrides show in the Model Browser by Bolding the Constraint’s name, and showing the offset Override in parenthesis after the name. See in the image below.
If I activate the Master position, the components dump their Overrides, and return to their natural positions. When I get ready to apply Joints, I’ll simply activate the ‘SimPrep’ Position before heading into the Simulation Environment.
That’s not all we can do with these things. Remember, we can access our Representation in Drawing views too.
While this particular Positional Representation is not how I want this Assembly detailed, you can see how awesome this can be when setting up drawing views. While there are many Drawing View options we cannot change once the view is created, the POSITIONS CAN BE CHANGED at will. Sweet !!
While this example was tuned to accessibility for Simulation prep, an obvious useful example would be to have the Bracket Assembly in Full open position.
This wasn’t the most complex example, but we were still able to review some of the options and possibilities that are available. When you need a named feature that will alter the positions and status of components in a predetermined manner, then consider Positional Constraints. Combining these with View Representations can produce some powerful combinations.
One thing missing is Autodesk Inventor Publisher’s access to these Representations. Since we might often pre-position Sub-components in a semi exploded state for ease of modeling, many saved positions could be accessed and save numerous hours of needless work.