To iLogic or not to iLogic – Let’s begin with Parameters

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So, where do we begin?

First we need to understand the basics of how to drive the shape of an Inventor model through model and user parameters.

When you start dimensioning a sketch, you will notice it automatically puts a letter and number next to Edit Dimension which starts from d0, d1, d2 etc. These are called model parameters.

inventor model parameters

When prepping the sketches and features for iLogic programing, we want the names to have meaning as d0 and d1 are not very descriptive. So let’s give it a description.

We can do this one of 2 ways, either typing it in the dialog box.

iLogic dialog box

Or, if you have already typed in the value (1000) without putting in a parameter name and would like to change the parameter name, you can open the parameters dialog box and change the default parameter (d0) to something that is more recognisable.

You can find this under the Manage tab.

Inventor Manage Tab

Inventor Manage Parameters

Inventor Change Model Parameters

(Please note that you cannot have spaces between words. You will need to use an underscore and also take note that the parameter name is case sensitive.)

We can make this model parameter into a multi-value. (This will allow us to drive the model with iLogic using pre-set values for the length of the table.)

Inventor Parameter Values

Right click anywhere on the line item and click on Make Multi-Value. In the Value List Editor you can add the additional values you want to choose when driving your iLogic model and then click add.

Value List Editor

Below are the added values.

Add Values

Now, if you look at the Parameters dialogue box, you will see a drop down arrow next to 1000mm. If you click on it you will see the rest of the values that we inserted.

Parameters Dialogue Box Values

What this means is that for the length_of_table_top parameter we can only have those values that we have inserted as our multi-value.

The second way to drive the dimensions is to insert user parameters.

These can be obtained in a number of ways.

Inputting it directly into the parameters dialog box will allow us to insert 3 different types of parameters.

  • Numeric
  • Text
  • True/False

Model Parameters Dimensions in Inventor

You can also link in user parameters from another Inventor file or an Excel spreadsheet.

Importing Inventor Parameters from Another File

I am going to import user parameters from another part file. This file will be the basis for skeletal modelling. (This is for another post.)

Import User Parameters from External Inventor Part

To link the user parameter with a newly created dimension, select the arrow next to the text and click on List Parameters.

Link User Parameter With A New Dimension

Link User Parameter With A New Dimension - Width of Table

After choosing width_of_table, this dimension will now be driven by the user parameter imported from the Inventor file.

You can also insert equations into the parameter fields and drive the model through one or maybe two parameters. Just remember BODMAS 😉

We can now extrude the table top and add a material.

We are now ready to drive this table through iLogic by choosing what the length is. It will automatically choose the width and also specify between two or maybe three different material types.

Next up: To iLogic or not to iLogic – If….then….end if

Kind regards,
Aldred, the Mad Hatter