Changing Content Center Parts in Inventor with iLogic


Content Center Parts in Inventor

The iLogic snippet to add a Content Center in Inventor part is really powerful. Not only does it make the placement process so easy, it also lets us change the size of a content center part that has already been placed.

This is a follow-up to our recent AVA session “Automated Assembly Generation with iLogic”, so be sure to check that out.

The video below demonstrates how this works, so take a look at it and then we will break down the details of the iLogic code below.

Below is the iLogic rule from the video.

Quick Summary for iLogic with Content Center in Inventor

Lines 1-2 exist to make sure this rule is automatically triggered when the size parameter is changed. The local variable “trigger” serves no other purpose.

Lines 4-8 create some local variables for storing values that will be used later in the rule. These values are calculated from parameters in the bracket part. As the bracket changes size, the new values need to be extracted from the bracket part.

Lines 10-15 place the bolt part from the content center using the iLogic AddContentCenter snippet. The AVA video explains this snippet in more detail, and some additional notes are given below.

Lines 17-18 constrain the bolt to the first hole in the bracket. See the AVA video for more info on this iLogic snippet.

Lines 20-25 create a rectangular component pattern using the iLogic pattern snippet. The AVA video gives more detail on this iLogic function.

Adding the content center part

When adding a content center part, the easiest way to make sure you are choosing a unique row from the family table is to use the key columns in the snippet. This is demonstrated in the AVA video. But it is possible to use any column, and there are times when a non-key column might be a better choice.

For example, this rule has parameters that are driving the diameter and length of the bolt. These parameters are numeric, decimal values. But the key column for bolt diameter is a text string which represents the fractional diameter value:

Instead of writing some complex string function to convert a decimal value into a mixed-number fraction, I can simply choose a different column for the bolt size that uses decimal numbers. Looking at the table view tab for this family, I find a column named Nominal Diameter. Hovering the mouse over the column title gives me the unique internal name of this column: THREADDIA.

This column represents the same data as the key column, but in a more convenient numeric format.

So, looking at line 13 in the code, you can see that the column names I have chosen are “THREADDIA”, “NLG”, and “TS”, and their values are boltDiameter, boltLength, and “UNC”, respectively.

“NLG” is the internal name of the nominal length key column. Since the “NLG” and “THREADDIA” columns contain numeric decimal values, I can use my boltLength and boltDiameter variables in the snippet.


If you have any questions about any of the information we went over today or anything related, feel free to reach out to us and we will help you out. You can also email our lifeline team at or give us a call at 1-866-465-3848.



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