At the heart of any design we can find an idea.
From that idea design intent is born
Design intent is then stripped down to rules that are reduced to simple expressions or variables.
This is where the Variables Table takes its meaning
In this article I will introduce in an in depth way this essential tool needed to create a parametric model.
Types of variables
Two types of variables can be found
- Dimension (Dim)
- Variables (Var)
Type of variables – Dimensions
Dimensions are created when users place dimensions inside a sketch. To help identify them, in the column “Type” you will see the “DIM” mention. This indicates value is extract from the 3D model.
Note: PMI (Product Manufacturing Information) also creates DIM entry in the table. Later in the article I will show how to filter those variables.
Type of variables – Variables
Variables can be created by the system or by the user. To help identify them in the column “Type” you will see the “VAR” mention.
When the system creates variables, this has a direct impact on the morphology of the model.
When users create variables, no direct impact on the morphology of the model can be seen unless you link to geometry through a formula.
Exemple of user VAR
By making combinations of Dimensions and Variables you can define rules that will manage the design intent
- Control a dimension with another dimension (Dimension A = Dimension B).
- Define a variable (pi=3.14).
- Control a dimension with a formula (Dimension A = pi * 3.5).
- Control a dimension with a formula and another dimension (Dimension A = pi * Dimension B).
- Control a dimension with a formula that includes a function (Dimension A = Dimension B + cos(Dimension C)).
- Control a dimension with a value from a spreadsheet, such as a Microsoft Excel document, by copying the value from the spreadsheet into the Variable Table with the Paste Link command. You can use any spreadsheet software that can link or embed objects.
Note: Excel can be used but I recommend you avoid externalizing information for better management and interaction etc…
When dimensions ( variables) are extracted from the 3D model, unit is automatically defined by the system.
On the other hand a “Var” created by a user needs to have its unit defined.
Here is the list of unit types available, sorry for this one my french readers got the lead J
|Masse||Flux de chaleur par unité de surface|
|Heure||Flux de chaleur par unité de distance|
|Température||Source de chaleur|
|Intensité lumineuse||Accélération linéaire|
|Quantité de matière||Linéaire par angulaire|
|Angle solide||vitesse linéaire|
|Accélération angulaire||Flux lumineux|
|Moment angulaire||Force magnétique|
|vitesse angulaire||Flux magnétique|
|Surface||Densité du flux magnétique|
|Force mécanique||Taux du débit de masse|
|Coefficient de dilatation||Moment d’inertie de masse|
|Densité||Masse par unité de surface|
|Capacitance électrique||Masse par unité de longueur|
|Force du champ électrique||Proportionnel à la distance|
|Différence de potentiel électrique||Quantité d’électricité|
|Résistance électrique||Intensité du rayonnement|
|Énergie||Rigidité de rotation|
|Entropie||Second moment de surface|
|Coefficient de film||Conductivité thermique|
|Force par unité de surface||viscosité cinématique|
|Force par unité de distance||Volume|
|Taux de débit volumétrique|
|Scalaire (sans unité)|
To define the “Variable” unit, use the drop down menu at the top left.
On the right of the drop down menu for units, click the small funnel icon.
The Funnel tool helps filter what is visible inside the table.
Filter – Type
Users choose the type of variable that will be visible.
- User Variables
- PMI Dimensions
Note: In traditional modeling PMI data helps create reference information for the manufacturing. Since they are references, the background of those cells will be gray out.
Filter – Named by
Each new entry in the table gets a default name by the system or one defined by the user at the creation of the “VAR”.
At anytime the user can redefine the name to ease the management of the entry in the table.
As a rule of thumb you should rename only the variables that you change frequently. This way you will be able to create some kind of form by filtering the table. The column “Description” could also be use to add an extra level of filtering.
- Users – Display only variables named by the user
- System – Display only the variables who do not need to be renamed ( they have their original system name)
- Both – Both are displayed
Note: To have a variable return to its initial name, simply delete the content then press ENTER
Filter – Graphic In
Allow filter variables base on:
- Last Selected Window – Displays variables that are associated with elements in the active window.
- Select Set – Displays variables that are associated with elements in a group that you have selected in the document.
- File – Displays variables that are associated with elements in the current document.
On the right side of the filter button, the formula button guides users to establish basic formulas.
One example, is the formula that can be write to round off to the 16th.
Figure 1 – Decimal display
Figure 2 – Fraction display
Formula – Round off Rules
Solid Edge offers two ways to round value. (This feature is associated to dimensions placed inside sketches not directly in the table)
- First round off is base on the rule of .5. This one round off to the upper value (.625 = .63 / .635 = .64)
- Second round off is base on the odd value. (.625 = .62 / .635 = .64).
This second rule has the advantage to distribute the round either up or down. This is the default use in Solid Edge.
For each Dim user has the choice between the two. ( RMB click on a dimension inside a sketch then choose properties)
Variable rule editor
For each variable, users can decide what rule will be enforced to establish the range of the variable value.
Variable rule editor – Value base on
Here users define how the variable will be fed:
- Base on a formula (Formula can be any algebraic equation)
- Base on a link
Link is comparable to what can we found in Excel. The link can be established between two cells of the same table. If a link is established between two parts/assemblies/drafts this workflow is called Peer Variable.
Variable rule editor – Limit value to
Users can limit the value of a variable to a range of value. Two choices are offered
- Discrete list ( 20;30;35;45)
- Minimum/Maximum value
Minimum and maximum value can be set based on:
- Maximum/minimum or equal
- No maximum/minimum
The Columns help manage the data inside the table. Users can double click on the column header to sort values.
Columns can be reordered by simply drag’n dropping the header
With the RMB a contextual menu can be accessed with regular windows features like:
Column – Expose
See previous article
Video for this article shows the exposed functionality.
Cell with a gray background indicates it cannot be edited directly. Most of the time those cells refer to a reference value or the value is pushed by an external formula.
A contextual menu is available for each cell of the table.
Cell – Peer variable
Previously I talked about establishing a relation between two cells. Here is a quick instruction:
- From the source table, highlight the line then from the contextual menu click « Copy link ».
- In the destination table, highlight the destination line then from the contextual menu click « paste link ».
Video for this article show the expose functionality.
Manipulate the table
So far we have seen the process that runs inside the variable table, what’s left is to take a look at the technicals inside the context of a modeling project.
What can be better than doing so through an interactive tutorial?
A variable table is more than just a table to store numbers; it is the brain behind your design.