Tutorial: Preparing CAD Geometry

Learn how to break a part into multiple parts, copy reference geometry, trace curves, and use Boolean intersection to create a new part.

In this lesson you will learn how to:
  • Import a CAD model
  • Break a part into multiple parts
  • Copy reference geometry
  • Trace curves using sketch tools
  • Pull a sketch curve into a solid
  • Use Boolean intersection to create a new part
  • Define a design space


Import the CAD Model

  1. Press F7 to open the Demo Browser.
  2. Double-click the arm_straight.x_t file to load it in the modeling window.


  3. Make sure the display units in the Unit System Selector are set to MMKS (mm kg N s).
  4. If not already visible, press F2 to open the Model Browser.

Copy Reference Geometry

  1. Use the middle mouse button to adjust the view so the model is positioned as shown below.


  2. Click the icon in the lower left corner of the modeling window to Switch to Orthographic Projection.
  3. Double-click the side face of the break pedal twice to enter sketch mode.
    A sketch plane is created perpendicular to the selected face, and the edges of the face are outlined in red.


    Note: The red reference lines are created only on the side face of the brake pedal, because this is the only face that touches the sketch plane.
  4. Click the Create New Part button on the microdialog to place what you are about to sketch into a new part, which appears in the Model Browser.


  5. Click the Convert Lines icon on the sketch toolbar, or right-click one of the red reference lines and select Create Curves from All Reference Lines from the context menu.


  6. The reference lines are copied and now appear black.


  7. Double-right-click to exit sketch mode and enter push/pull mode.


Pull the Sketch Curve into a Solid

  1. Click the cube icon next to the original part in the Model Browser to hide it in the modeling view.
    Only the new part you just sketched is now visible.


  2. While in push/pull mode, click and drag on the face to extrude it into a pedal. Be sure to extend the face away from you beyond the far edge of the pedal in the original model.


  3. Double-right-click to exit push/pull mode.
  4. Click the cube icon next to the original part in the Model Browser to make it visible in the modeling view again, and left-click to deselect all objects.


Use Intersection to Create the Pedal

  1. Select the Boolean tool on the Geometry ribbon.


  2. Select the Intersect tool from the secondary ribbon.


  3. Click on the brake arm in the modeling window to select it.


  4. Click Tools on the guide bar.


  5. Click on the pedal (the part you extruded in the previous step) to select it.


  6. Select the Keep Targets check box on the guide bar.


  7. Click the Intersect button on the guide bar to perform the operation. Double-right-click to exit the tool and then select the brake arm.
    The pedal and the arm are now two separate parts.


Copy Individual Curves

  1. Another way to duplicate geometry is to copy individual curves. Adjust the view and use the scroll wheel to zoom in on the primary cylinder, as shown below:


  2. Double-click the face of the primary cylinder once to enter push/pull mode, then double-click again to enter sketch mode.
    A sketch plane is created perpendicular to the selected face, and the edges of the face are outlined in red.


  3. Right-click one of the edges of the face and select Create Curve from the context menu. Repeat this step for all four outer edges of the face, but not the interior circle.


  4. Once selected, the outer edges of the primary cylinder should appear black.


  5. Click the Transfer Sketch icon on the sketch toolbar to transfer the sketch you just created to a new part.


  6. Double-right-click to exit sketch mode and enter push/pull mode.
  7. Click and drag to extrude the sketch into a solid. Be sure to click inside the circle so that you select the whole face.


  8. Right-click and mouse through the check mark to exit, or double-right-click.

Use Intersection to Create the Primary Cylinder

  1. Select the Boolean tool on the Geometry ribbon.


    The Intersect tool is activated, with Targets selected.


  2. Click on the brake arm in the modeling window to select it.


  3. Click Tools on the guide bar.


  4. Click on the primary cylinder in the modeling window to select it.
    The Keep Targets check box should already be selected.


  5. Click the Intersect button on the guide bar to perform the operation.
  6. Double-right-click to exit the tool and then select the primary cylinder.
    The primary cylinder and the brake arm are now two separate parts.


Use Sketch Tools to Trace a Curve

  1. A third way to duplicate geometry is to sketch over an existing curve using sketch tools. Adjust the view and use the scroll wheel to zoom in on the coupling, as shown below:


  2. Select the Circle by Center and Point tool on the Geometry ribbon.


  3. Click the face of the coupling.
    A sketch plane is created perpendicular to the selected face, and the edges of the face are outlined in red.


  4. Select the New Part icon on the sketching toolbar.


  5. Draw a circle on top of the outer circle of the coupling by clicking once to place the center point, and again on one of the quad points of the outer circle.


  6. Double-right-click to exit sketch mode and enter push/pull mode.
  7. Click and drag to extrude the sketch into a solid. Be sure to click inside the circle so that you select the whole face.


  8. Double-right-click to exit push/pull mode.

Use Intersection to Create the Coupling

  1. Select the Boolean tool on the Geometry ribbon.


    The Intersect tool is activated, with Targets selected.


  2. Click on the brake arm in the modeling window to select it.


  3. Click Tools on the guide bar.


  4. Click on the coupling in the modeling window to select it.
    The Keep Targets check box should already be selected.


  5. Click the Intersect button on the guide bar to perform the operation.
  6. Double-right-click to exit the tool and then select the coupling.
    The coupling and the brake are now two separate parts.


Define a Design Space

  1. Adjust the view so that you can see the entire brake, as shown below:


  2. Click the icon in the view controls at the lower left of the application to Switch to Perspective Projection.


  3. Right-click on the arm of the brake and select Design Space from the context menu.


  4. Click on empty space.
    The design space appears reddish brown.


  5. In the Model Browser, rename the brake's parts arm, pedal, primary cylinder, and coupling.
    Click on a part once in the Model Browser to select it, and again to make the text field editable.


  6. Click on empty space to deselect all parts.
    The imported CAD geometry has now been prepared for optimization, with the arm of the brake designated as a design space (the part that material will be carved away from during optimization), while the pedal, primary cylinder, and coupling have been designated as separate, non-design spaces.