Creating Edge Fillets Using Variable Radii

You can create an edge fillet using variable radii.

In this type of fillet, the radius varies at selected points along a selected edge.

The fillet surface is obtained by rolling a sphere, which radius would vary, over the selected edge.

This task shows you how to:

Before you begin: Create a 3D shape containing a surface with a sharp edge.
See Also
Creating Bitangent Shape Fillets
In the Knowledge Base
The position of the additional variation points remain unchanged even after modifying the sketch

Create an Edge Fillet Using Variable Radii

You can create an edge fillet with variable radii using the Edge Fillet command.

  1. From the Refine section of the action bar, click Edge Fillet .
    The Edge Fillet Definition dialog box appears.
  2. In the Edge(s) to fillet box, select the edge to be filleted.
  3. Click Preview.
    The system detects the two vertices and displays the default radius value.

  4. In the Extremities list, select the desired type of extremity for the fillet:
    • Straight: no tangency constraint is imposed at the connecting point between the fillet and the initial support, generating sometimes a sharp angle.
    • Smooth: a tangency constraint is imposed at the connection between the fillet surface and the support surfaces, thus smoothing the connection.
    • Maximum: the fillet surface is limited by the longest selected edge.
    • Minimum: the fillet surface is limited by the shortest selected edge.
  5. In the Propagation list, select the propagation type:
    • Tangency: the fillet is propagated up to the first edge that is not continuous in tangency.
      Note: The tangent continuous edges of the selected edge are managed to ensure a better fillet stability and robustness (More fillets are automatically rerouted in case of design changes). The variable fillet radius is displayed at the end of the propagation of the selected edge.
    • Minimal: the fillet is propagated up to the first geometric limitation.
  6. To add an additional point on the edge to make the variable radius fillet, click the Points box and select a point on the edge.
  7. In the Radius box, enter a new radius value for this point.
  8. In the Variation list, select Cubic to obtain a smooth transition from one radius to another.


  9. Select the Conic parameter check box.

    It 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.
    Important:
    • Conical fillets do not handle twist configurations. If a twist is detected, the fillet operation fails.
    • Conical fillets may produce internal sharp edges. However, an healing operation is performed to smooth these sharp edges. For more information, see Healing Geometry.
    • If the fillet surface curvature is lower than the support curvature, the fillet surface relimitation may fail. In such cases, the conic parameter has to be decreased.
    • If the Conic parameter check box is selected, the Edge(s) to keep box and the No internal sharp edge check box are not available.
  10. Select the Trim support check box to relimit the support elements and assemble them to the fillet if needed.
  11. Click OK to confirm the operation.
    The surface (identified as EdgeFillet.xxx) is added to the tree.
    Important:
    • This is the fillet you would obtain using the Linear variation mode. In this case there is a straight transition from one radius to another.

    • For more information about the Edge(s) to keep option, refer to Creating Edge Fillets; about the Circle Fillet option, see Creating a Variable Radius Fillet Using a Spine; about the Blend Corner(s) and Setback distance options, see Reshaping Corners.

Limit Fillets

While creating the fillet, you can limit it by selecting an element (plane or surface) that intersects it completely.

  1. Once the edge to be filleted has been selected, and the radius in defined, click Preview then More>>.
  2. Click in the Limiting element(s) box, then select the trimming element(s).
    These elements can either be surfaces, planes, or points on edges.

    An arrow indicates which portion of the fillet is to be retained. If needed, you can click on this arrow to inverse it, to retain the opposite side of the fillet.

    Tips:
    • It is possible to use one or more limiting elements.
    • You can define a limiting element by clicking a point on one of the selected edges to be filleted.
  3. Click OK to create the limited fillet.
    In the illustration, the limiting surface has been hidden.



    • You can create limiting elements just by clicking on the edge to be filleted.

      The app displays this element as a blue disk.

    • You can select points as limiting elements. These points must be located on the edge to be filleted and they must have been created using On Curve available in the Point Definition dialog box.

    • You can also define variable radius fillets on closed edges.

      However, the app defines a default vertex on closed edges when applying the Edge Fillet command. To define the fillet, you need to remove this vertex first of all, then use 3D points only.
      Important: The Linear variation mode is not valid for closed edges or closed sets of edges that are continuous in tangency. In these cases, the Cubic mode is automatically applied.
    • Ensure that the limiting element is not larger than the initial element, as illustrated here. If so, decrease the size of the limiting element as prompted by the warning message.

      Important: If the Conic parameter check box is selected, the Edge(s) to keep box and the No internal sharp edge option are grayed out. Conversely, if the Edge(s) to keep box or the No internal sharp edge option is selected, the Conic parameter check boxes disabled.

Trim Overlapping Fillets

In some cases, fillets may be overlapping. The Trim ribbons option lets you solve this by trimming the fillets where they overlapping.

Select the Trim ribbons check box.

Important: Make sure the support involved does not present any sharp edge, because the fillet would be relimited, and may yield unexpected results, or could not be computed. For example, in the illustration, the fillet cannot be propagated along the whole edge because the fillet is stopped onto the vertical edge.

In this case, you should try to remove this discontinuity by either filleting the sharp edge or modifying the support surfaces.



For more information on this option, refer to Creating Edge Fillets.

Minimize Internal Sharp Edges

You can minimize the internal sharp edges generated during variable radius fillet computation.

When computing variable radius fillets, the app may generate internal sharp edges when the surfaces to be connected are continuous in tangency but not continuous in curvature.

Select the No internal sharp edges check box.

This removes all possible generated edges and improves your design

Important: If it is selected, the Conic parameter check box is not available.

Fillet Volumes

You can create variable radius fillets to volumes.

  1. Click Edge Fillet .
    The Edge Fillet Definition dialog box appears.
  2. In the Edge(s) to fillet box, select the edge of the volume to be filleted.
  3. In the Radius box, enter the radius value.

    Here we define first Radius to 10mm and second Radius to 5mm.



  4. Click OK to create the fillet volume.



    Important: The Trim support check box is unavailable as it cannot be used with volumes.