Creating a Fillet Surface Using a Spine

You can create a fillet surface between two neighboring or intersecting surfaces using a spine curve as the fillet surface edge.

Recommendation: For commands creating transitions between surfaces, use a minimum order of 6 to obtain optimal results.

Before you begin: Open a 3D Shape containing two intersecting surfaces or neighboring surfaces with a common edge. You also need a curve running roughly along the intersection of the surfaces, or a surface edge.
See Also
About Approximation
About Creating Fillet Geometry
Using Selection Sets for Creating Fillets
Creating a Fillet Surface
Creating a Fillet Curve
  1. Select two surfaces and the spine curve.

    You can also select two sets of surfaces and a set of curves. Alternatively, you can use an automatically created spine curve (see Use an Automatically Created Spine Curve).

  2. From the Surfacing section of the action bar, click OmniFillet .
    A fillet surface is created by two lengths in the quadrant of the selected point positions (Variable two Lengths type).

  3. Optional: Click the invert normal handle to create the fillet surface in the quadrant to which the normals of the support surfaces are oriented.
  4. Change the continuity for Side A and Side B (see Continuities G0 - G3 on Side A).
  5. Define the Length values for the start and the end of both sides. They determine the length between the spine and the radius runout lines (RRLs) where the fillet touches the base surface (see Fillet Surface Spine Type).


  6. Click to edit the variable length functions for both sides from the start to the end of the spine.
    A 2D graph panel opens. Initially, the graphs show a straight line between the start and the end values.

  7. In the Side A/B Length Graph panel, you can:
    • Select the graph you want to show and edit: Side A, Side B, Side A and B, Both Sides.
    • Click Insert Point and select a position on the graph in the panel or on the spine curve in the work area to add a point.

    • Click to change it to . This links the change of all values at both sides.
      Note: The number of points on side A and B is always the same. With , the value of the points is also the same. With , you can enter different values for side A and side B.
    • Click Free or Constant to define a free or a constant portion at this inner point.
    • Edit the point's position by means of the value box or by dragging the handle.

    • Hover over a point on the graph or on the spine curve until it highlights, and press Backspace to delete this point.
    • Define the Length Shape Type: Local, Smooth, Global.
  8. In the Explicit Controls section, define the Tension values at the start and the end of both sides. They determine how much the surface is pulled toward the RRLs on each side.
    Tension at Side A for both Start and End
    Tension 0.1 Tension 1 (default) Tension 1.5
  9. Click to edit the tension functions for both sides from the start to the end of the spine.
    A 2D graph panel opens. Initially, the graphs show a straight line between the start and the end values.
  10. In the Side A/B Tension Graph panel, you can insert, edit, and delete points as described above for the length graph.
  11. Define the boundary condition of the weight function for tensions at the start and end of both sides. Select Free or Constant for Flow A and Flow B.
  12. Optional: Modify the Limitation Ends to limit the resulting fillet surface at its start or end (see Limitation Ends).
  13. Define the Parameterization of the fillet surface.
  14. Optional: You can click Go back to selection at any time to change the selection, define and use selection sets, or to choose another mode in the selector panel.

If the OmniFillet creation fails, the command locates up to five problematic areas on the input geometry. It encounters a gap that exceeds the topology tolerance when solving for a radius runout line. It highlights the area and displays the rounded gap value.

Gap DetectionZoomed In View




You can first correct the input surfaces using OmniMatch , for example, and then perform OmniFillet again.