This project will show you how to create an L-Shaped bracket, with parameters and 2D constraints. It is a practical project, designed to help get you started with 2D parametric drawing in BricsCAD. If you’re interested in 3D parametric modeling, be sure to check out this parametric drum kit tutorial. Both projects work with BricsCAD parametric blocks.

animating the parameters bricscad
By the end of this tutorial, you should be able to create something that looks like this.

↓↓ Jump to instructions ↓↓


This project will cover:

  • How to add constraints to a 2D drawing
  • How to create and edit the value of parameters
  • Simple animation of constraints and parameters
  • How to use a design sheet (Excel, Google Docs or similar) to create design variations
  • How to insert and modify the finished bracket as a parametric block reference in a drawing

Download the project .dwg files here

Watch the step by step video


Before we begin…

  • If you need to manually enter a value during the exercise, it will be shown in green.
  • All dimensions are shown in mm however you can use any unit you like.
  • 2D Geometric Constraints and 2D Dimensional Constraints are located in The Parametric tab of The Ribbon.the constraints in the parameters tab of the ribbon bricscad
  • You must have an understanding of how to draw basic shapes in BricsCAD. If you are not yet familiar, please see our Beginner CAD Course.

Quick guide to terminology:

  • Parameter – defines the position, distance, and angle of geometry
  • Constraint – a rule: position, slope, tangency, dimension, and relationship of geometry
  • Expression – formula or absolute value of a parameter or constraint

How to Make a Bracket With 2D Geometric and Dimensional Constraints

Time to complete: 1 ½ – 2 Hours

Difficulty: 7/10


Part One: The Building Blocks

  1. Draw an L-shape with a closed Polyline (PL) (as shown).
    draw l shaped polyline
    All units are mm, but you can use whatever unit you like.
    TIP Start at 0,0,0 in the bottom left corner
  2. Add a Fix Constraint to the bottom left corner (as shown).
    The Fix Constraint is the lock icon located in the 2D Geometric Constraints Section of the Parametric Tab on the Ribbon.fix constraint in the ribbon bricscad
  3. Draw two circles (C) with a radius of 2 (as shown). These will be the drill holes in the bracket.
    all units are in mm, but you can use whatever you like.
  4. Add a Radius Constraint to the two circles.radius constraint
    The Radius Constraint is the Circle icon, with a lock, located in the 2D Dimensional Constraints Section of the Parametric tab on the Ribbon.the radius constraint
  5. In the Mechanical Browser panel add a new parameter. Right-click Parameter and select Add new parameter from the drop-down menu.add new parameter bricscad
    TIP You can also use the Parameters panel.
  6. Click on the new parameter and change the values:

    Name hole

    Expression 1.5

    edit the parameter in the mechanical browser

  7. Select the two radius parameters and change the Expression to hole.
    Note The circles should change size if you complete this step correctly.
  8. Check your work so far: right-click the hole parameter and select Animate from the drop-down menu. If you have completed all the steps correctly, you should see the two circles become larger and smaller.animate the parameters
  9. Save your drawing.

Part Two: Add Constraints

  1. Add Horizontal Constraints to the lines shown in dotted yellow.horizontal constraints
    The Horizontal Constraints icon looks like a red and white equals sign, located in the 2D Geometric Constraints Section of the Parametric Tab on the Ribbon.
  2. Add Vertical Constraints to the lines shown in dotted yellow.
    The Vertical Constraints icon looks like a sideways red and white equals sign, located in the 2D Geometric Constraints Section of the Parametric Tab on the Ribbon.vertical constraints button on the bricscad ribbon
  3. Add Linear Constraints and change their names (as shown).linear constraint parameters
    The Linear Constraint icon is the icon with crossed arrows and a lock, located in the 2D Dimensional Constraints Section of the Parametric Tab on the Ribbon.linear constraints on the bricscad ribbon

    TIP Add vertical parameters starting from the bottom. Add horizontal parameters in a clockwise direction, starting from the fix point.
  4. Animate the constraints to see how they change your drawing.
  5. Save your drawing.

Part Three: Working with Arrays

  1. Create a Rectangular Array with the bottom circle.

    Number of columns: 3

    Distance between columns: 10

    Number of rows: 1

    Distance between rows: 10

    array

  2. Create a Rectangular Array with the top circle.

    Number of columns: 1

    Distance between columns: 10

    Number of rows: 2

    Distance between rows: 10

    array

    Note It is important to add constraints (such as radius constraints) before you create an array.
  3. Rotate the array 180°.rotate the array
  4. In the Mechanical Browser panel, right-click and animate the hole parameter.
    Nothing should happen. This is because the parameter is not yet linked.
  5. Right-click the hole parameter on each array and select Link to parameter.link to parameter in the mechanical browser bricscad
  6. Repeat step 4. This time you should see the circles change size.animate parameters
  7. Add 4 new Linear constraints (as shown).linear parameters constraints bricscad
    TIP Use the bottom left corner and top right corner as the first pick point and the center of the circles as the second pick point.
  8. Add 1 new parameter:new parameter

    Name: gap

    Expression: 5parameter editing

  9. Change the Expression of the 4 new, linear constraints to gap.
  10. Add 4 new parameters:

    Name: nw

    Expression: width/10

    Name: nh

    Expression: height3/10

    Name: mw

    Expression: width2/10

    Name: mh

    Expression: (height-height3)/10

  11. In the Mechanical Browser, click on the array that goes horizontally. Change the values:

    Columns: nw

    Rows: nharray parameters

  12. In the Mechanical Browser, click on the array that goes horizontally. Change the values:

    Columns: mw

    Rows: mh

  13. To understand how these parameters work, try adjusting the Expression of the width or height parameters. If you have completed all the steps successfully, you should see an extra hole for every increase of 10, to the Expression of the width, width2, height and height3 constraints.array animation
  14. Save your drawing.

Part Four: Ad a Design Table

  1. Create a spreadsheet with the parameters of your various bracket layouts. Make sure that the column name matches the value of the parameters. The row name will become the name of each arrangement.csv file in google docs
    Note It is also possible to create this file using a simple text editor, such as Notepad.
  2. Save As a .csv file.
  3. In BricsCAD, enter DESIGNTABLE.
  4. Choose the From file option.
  5. Select the .csv document you wish to use.
  6. Click Open.
  7. A new parameter should appear in the Mechanical Browser panel. With a selection of options in a drop-down menu. Use this to switch between the different layouts.option for your drawing
    Choose your layout from the drop-down menu.

    animating the parameters bricscad
    For clarity, some of the parameters have been hidden.
  8. Save your drawing.

Part 5: Insert Your Drawing as a Parametric Block

  1. Open a new drawing.
  2. Enter INSERT.insert parametric block bricscad
  3. Click Browse.insert parametric block dialog bricscad
  4. Select the file and click Open.click open file
  5. Click OK.block dialog
  6. Click to place the block in the drawing.
  7. Select the block.
  8. Open the Properties panel. Under the Parameters section you will see a drop-down menu offering you the different layout variations. Use this to cycle through the various options for the bracket layout.parametric block options in the properties panel
Note In the exercise, the gap parameter remains editable. If you do not wish to see this when your block is inserted into a drawing, add “gap” as a column in the .csv file and set the value for each arrangement.
These changes are not automatically loaded, you will need to reload the .csv file to the original drawing reload the block insert in any of the drawings it has been inserted to.

It Doesn’t Stop There!

Once you’ve got the hang of 2D Constraints and Parameters in BricsCAD, the sky’s the limit!

parametric plus l shaped t bracket


Disclaimer: The aim of this tutorial is not to show you the best method for working with constraints, but simply give you a starting point from which to build your own skillset.