Consider the example shown below of one element junction with different angles on both sides. Here, one angle is detected with the default tolerance (edge in blue), while the other is not. In such case, it is necessary to change the default tolerance.

The auto-detection procedure uses default tolerances which are optimal for most grids. The tolerances button gives access to the detection thresholds dialog box where values can be better tuned for a specific grid.

Detect edges enables edge detection. If disabled, only the edges provided in the initial grid are used to reconstruct the geometry.

Max face angle adds edges whenever the angle between two surfaces is greater than the specified value. A lower value detects more edges, but may create undesired edges especially when the grid is too coarse to represent the geometry.

Max curve angle adds prescribed points onto curves if the angle is less than the input value. The edge is then split in two and a prescribed node is introduced at the breaking point.

If Keep edited edges is selected, the selected tolerances will not erase edges added manually using the edition tools.

Unselect Detect edges and Keep edited edges to apply a full reset, and only consider edges provided by the input grid.

The Refresh CAD icon performs the edge detection operation and refreshes the display.

Reset sets the detection thresholds to their default values.

The Unconnected edge filter option enables a filter to remove automatically most of CAD detection artifacts. These artifacts are small isolated edges not related to the geometry.

Unconnected curves is an orphan curve created during the detection process, which is not connected to any other curves at its end points. The curve is erased if its length is less or equal to the specified value.

Connected curves. Same as standalone curve, but the curve is connected to another curve at only one of its ends. The curve is erased if its length is less or equal to the specified value.

The edge filter is applied on detected edges only and will not remove user-created curves.

Example 13.1: Standalone Curves

Figure 13.4: Initial Mesh Edges

Figure 13.5: After Filtering Edges of Length <= 3

Figure 13.6: After Filtering Edges of Length <= 10

Example 13.2: Connected Curves

Figure 13.7: Initial Mesh Edges

Figure 13.8: After Filtering

The activation of this tool allows adding and removing edges manually by a right-mouse clicking the edge in the 3D window. Added edges are shown in white, while removed edges are in black:

Example 13.3: Example of Edge Addition (Added Edges in White)

Example 13.4: Example of Edge Suppression (Deleted Edge in Black)

Use Refresh CAD to commit the current modification and refresh the edge colors.

This tool allows adding a group of interconnected edges by clicking only one edge of this group. The edges are then connected one by one, if the connected edge is nearly parallel to the current one.

Transfer to selection mode:

and right-mouse click in the 3D window to add edges.

For example, the edges of this cube could be added manually, instead of using the auto-detection tool.

Figure 13.9: Initial Mesh, with No Edges. The X Mark Is the Edge Selected with Define Curves

Figure 13.10: The Group of Edges Detected Is Shown in Red. Parallel Edges Connected to the Initial Edge Were Selected Automatically

Figure 13.11: The Tolerance Control Allows Connecting Edges That Are Not Parallel, as Shown Below

Prescribed points are separations between edges. Edges can be split in two by adding a prescribed point at a given position, or joined together by removing the prescribed point.

While the edit curve breaks tool is active, existing prescribed points are shown with red dots. Transfer to selection mode   and right-mouse click a node position to add and remove this point. New prescribed points are shown in white, while removed ones are in black.

When this tool is active, right-mouse click an edge to delete it. However some mandatory curves cannot be deleted.

The Refresh CAD icon   saves the current edition and clears the undo history. The graphical display is refreshed, displaying the edges defined on the CAD in bright colors.