Creating Bitangent Shape Fillets

You can create a shape fillet between two surfaces. The fillet surface is obtained by rolling a sphere between the selected surfaces.

This task shows you how to:

Before you begin: Create a 3D shape containing two surfaces intersecting each other.
Related Topics
Creating Tritangent Shape Fillets
Creating Edge Fillets
Creating a Variable Radius Fillet Using a Spine
Creating Laws

Create a Bitangent Fillet

You can create a bitangent fillet by defining supports and radius.

  1. Click Shape Fillet in the Fillets sub-toolbar.

    The Fillet Definition dialog box appears.

  2. In the Fillet type list, select BiTangent Fillet.



  3. In Support 1 box, select a surface as the first support element.

  4. In Support 2 box, select another surface as the second support element.

  5. Select the fillet mode:


    • Radius: enter the value of the fillet radius.
    • Chordal: enter the value of the fillet length. For more information, refer to Creating Chordal Fillets.

    Up to four fillet locations may be possible. To help you decide on the location an arrow is displayed on each selected surface. You can click on the arrows to specify the desired fillet location.



  6. Select the Conic parameter check box. This check box allows you to vary the section of the fillet.

    Important: For a parameter comprised between or equal to:
    • 0.5: the resulting curve is a parabola
    • 0 and 0.5: the resulting curve is an arc of an ellipse
    • 0.5 and 1: the resulting curve is a hyperbola.

  7. Use the combo to choose the desired type of extremity for the fillet:


    • Smooth: a tangency constraint is imposed at the connection between the fillet surface and the support surfaces, thus smoothing the connection.

    • Straight: no tangency constraint is imposed at the connecting point between the fillet and the initial supports, generating sometimes a sharp angle.

    • Maximum: the fillet surface is limited by the longest selected support's edge.

    • Minimum: the fillet surface is limited by the shortest selected support's edge.

  8. Click Preview to see the filleted surface:



  9. Click OK to create the shape fillet.

    The surface (identified as Fillet.xxx) is added to the specification tree.

Important: In case the selected supports are partially tangent, it is advisable to create an edge fillet.

Create a Bitangent Variable Radius Fillet

You can create a bitangent fillet having variable radius. The radius of the bitangent fillet is varied using laws and relimiters.

Create a BiTangent Fillet With Spine and Hold Curve

You can generate a variable bi-tangent radius fillet by selecting a Hold curve.

In this case, you need to select a previously defined limiting curve that will control the fillet radius, and a previously defined spine that defines the planes in which the filleted surface section will pass. Both these curves must be larger than the surfaces involved, and the Hold curve must lie on one of these initial surfaces. The resulting filleted surface is tangent to the initially selected surfaces and limited by the hold curve.

  • Clear the Radius box as the hold curve defines the variable radius.



    For more information, refer to Creating a Variable Radius Fillet Using a Spine.

Create a BiTangent Fillet With Laws and Relimiters

You can create bitangent fillets by defining laws and limitations to spine and surfaces.

Important: The Law button becomes available when the Spine box is filled in.

  1. Select two surfaces.

  2. Select a line as the spine.

    Law relimiters are displayed on each extremity of the spine to delimit the radius law range. Manipulators enable you to move them along the spine.



    Tip: You can use a close spine, in that case, only the Law Relimiter 1 box is enabled.

  3. Click Law... to display the Law Definition dialog box. In this case, you need to select a law.

    The 2D viewer enables you to preview the law evolution before applying it.



    The Law Viewer allows you to:


    • visualize the law evolution and the maximum and minimum values,
    • navigate into the viewer by panning and zooming (using to the mouse),
    • trace the law coordinates by using the manipulator,
    • change the viewer size by changing the panel size
    • reframe on by using the viewer contextual menu
    • change the law evaluation step by using the viewer contextual menu (from 0.1 (10 evaluations) to 0.001 (1000 evaluations)).
    Important: You can check Inverse law to reverse the law as defined using the above options.

  4. Enter Start and End values.

  5. Choose the type of law to be applied to the radius.

    Five basic or advanced types are available:

    • Constant: a regular law, only one value is needed.
    • Linear: a linear progression law between the Start and End indicated values.
    • S type: an S-shaped law between the two indicated values. The pitch distance will vary between these two pitch values, over the specified number of revolutions.
    • Advanced: allowing to select a Law element.
    • Implicit: allowing the selection of points on the spine the association of values for these points.

      a. Select points on the spine. By default, the spine extremities (relimiters) are selected.

      b. Define a radius for each point. For instance, set 30mm for Point.2 and 60 for Point.3. The radius law applies between these two points. The radius values are interpolated into a curvature continuous radius law defined over the whole spine curve.

      c. Create a third point between Point.2 and Point.3 with a radius of 90mm.



      d. Define the Interpolation Mode: Linear (straight interpolation) or Cubic (smooth interpolation).

  6. Click Close to return to the Fillet Definition dialog box.

  7. Click Preview to see the filleted surface:



    Important:
    • The spine curve must be curvature continuous.
    • At least two points must be selected on the spine.
    • If the spine is closed, only one point is selected.
    • You can edit a point, by right-clicking it and choosing the Edit Point contextual item.
    • You can add a point by right-clicking and choosing the Create Point contextual item.
    • Points are automatically reordered in the list, according to their ratio on the spine.

Create a BiTangent Fillet with Multi-ribbons

You can create a bitangent fillet with the multi-ribbons.

The Faces to keep box lets you manage multi-ribbons.

  1. Select two surfaces.

  2. Set the Radius value as 20.

  3. Click Preview.



    As you selected two ribbons, an error message pops up asking you to process each ribbon in a separate operation.

  4. Click OK in the dialog box.

    The solutions are shown in red:

  5. In the Faces to keep box, select the face(s) you want to keep to create the shape fillet.



  6. Click Preview to see the filleted surface.



    You can clear Trim support1 and Trim support 2. In this case, the support element involved will not be trimmed and assembled to the filleted surface. By default, both options are checked, thus relimiting both support elements.

    Warning: Trim Support options are only available with the Generative Shape Design 2 product.

    In the examples below, we changed the filleted surface's color to better visualize it:

    With only one support element trimmed

    With both support elements trimmed