Creating Sketch Fillets

The Sketch Fillet option rounds off the corner that is formed between two lines on a sketch.

You can only create a fillet between two lines at a time: these lines can be two straight lines, a straight line and a curve, or two curved lines. The two lines can be disjointed, intersecting or have a common end point.

To create a sketch fillet:

  1. Select the two sketch lines that you want to fillet.
  2. Right-click on one of these lines and select Sketch Fillet.

    The Dimensions dialog appears.

  3. Enter the radius of the fillet in the Fillet Radius textbox. You can define the fillet radius as a numerical value, or as an expression using design parameters.
  4. If you set up a design parameter and want to expose it, activate the Expose Parameter?.
  5. Click OK.
The fillet is applied to the selected entities.

Two sets of tangent and coincidence constraints are added to the sketch when the fillet is created. A radius dimension is also created. You can edit the radius dimension to control the fillet radius.

Note The fillet radius must be smaller than the length of the shortest sketch line.

You can undo/redo the sketch fillet feature using the appropriate buttons in the Sketch in-place dialog.

Intersecting Lines

You can create fillets between intersecting lines. Simcenter STAR-CCM+ retains the longest portions of the selected lines, and creates a fillet at the point where they cross. This operation is shown in the following diagrams:

There are two fillet locations (the two intersections), Simcenter STAR-CCM+ chooses the lower intersection as this leaves the longer line segments. The remaining parts of the intersecting lines are discarded:

The sketch entities remain selected after the operation so that you can create a fillet again without the need to reselect the entities. In the example, creating a second fillet would connect the lines at the top:

Disjointed Lines

You can create fillets between disjointed lines. Simcenter STAR-CCM+ extends each line to a point where it meets with the other line, and creates the fillet there. This operation is shown in the following diagrams:



Non-Intersecting Lines

You can create fillets between two non-intersecting sketch features. Simcenter STAR-CCM+ places a fillet at the point that retains the two longest segments of the features.

In the following example, there are two possible places where a fillet could be placed (based on the specified fillet radius). The longest segments are retained when the fillet is placed on the top right, as shown highlighted in red:

3D-CAD therefore chooses this location, and the remaining segments are discarded: