Match Constraint Dialog Box

The Match Constraint dialog box contains controls which help you connect two or more surfaces or curves.

The Match Constraint dialog box appears when you click Matching Constraint from the Edition section of the action bar.

This dialog box contains controls for:

This page discusses:

See Also
About Creating a Matching Constraint
Creating a Matching Constraint

Elements

Source
Defines the source element to be constrained: an edge for surface, a vertex for curve.
Target
Defines one or two target elements on which the source element will be constrained: edges, planes, curves or vertices.
The target elements are not changed. Datum and Feature point elements are also supported as target elements for G0 continuity.
Invert
Only available if only one target element is selected.
Swaps source and target elements.

Limits

Partly
Matches the source edge to part of the target edge and specifies the limiting points via the selection fields.
This option is cleared when activating Inside option.
The snap manipulator lets you snap the vertex of the source element to a point.
Tip: For partial matchings, it is recommended to use Minimum Corner Distance in Me > Preferences > App Preferences > 3D Modeling > Styling > FreeStyle Shape Design, General tab, Matching Constraint command options section.

In case of partial matching constraints, gaps or overlaps may occur if the source surface corners do not coincide with the target surface corners. With Minimum Corner Distance, a corner distance tolerance is specified.

If the source surface corner is moved with the manipulator, it automatically snaps to the corresponding target surface corner as soon as its position is within the distance from the target surface corner defined by the tolerance.

Avoiding gaps with the Minimum Corner Distance option
This option is cleared when activating Inside option.

Approximated and Exact

Approximated
The control point distribution in the first control point row of the source element remains unchanged. This may cause larger continuity deviations.
Orders of continuity
(G3 in ICEM Shape Design only)
Specifies the matching transition.
Begin and End Edge continuities
(G3 in ICEM Shape Design only)
Aligns the cross tangents at the edges of the source and the target.
  • egin and End Edge continuities Cleared: All cross tangents will be aligned coplanar only, i. e. there may be an angle between the cross tangents of the source and the target.
  • Begin or End Edge continuities Selected: The beginning or end cross tangent of the source will be aligned collinear to the beginning or end cross tangent of the target.
  • Begin and End Edge continuities Selected: All cross tangents of the source will be aligned collinear to the cross tangents of the target.
Lock Boundaries
Fixes the selected boundaries of the source element. Only the other control points are moved. If both boundaries are fixed, only inner control points are moved.
Input geometry
Lock Boundaries at end of edge
Lock Boundaries at start and end of edge
Exact
This option is unavailable if Inside is selected.
Defines the continuity in case of matching curves.
In case of matching surfaces, the source element adopts the parametrization from the target element. Depending on the selected continuity, the control point distribution is influenced in the rows 1 (G0) to 4 (G3).
Exact cleared with G0 continuity
Exact selected with G0 continuity

Opposite Continuities

Source Opposite
Note: These options are only available if Diffusion is selected.
Defines continuities to be kept at the opposite curve end or surface edge of the source.
When using Diffusion option, control point/row modifications done to achieve the continuity with the target is propagated to other control points/rows than the ones directly involved by the specified continuity. This may move control points/rows at the opposite end or edge and thus modify the continuity at the opposite end or edge.
At the opposite source curve end point or surface edge, you can specify a maximum continuity to be kept using either the Max. list in the dialog box or in the work area the context menu available at the continuity labels which appear when Diffusion option is selected.
0 continuity is set by default, but you can select any other continuity irrespective of whether the order allows to keep it or not. If the continuity cannot be kept, the maximum possible continuity is applied and displayed under Applied in the dialog box and marked by asterisks in the context menu.
The Free option applies no continuity. This allows the movement of all control points or control point rows, without keeping any continuity, to obtain an optimal control point distribution with Diffusion. As in this case no continuity is kept at opposite, the continuity with neighboring elements at the opposite end point or edge may be broken.
Notes:
  • Matching constraints between source and target always have priority over the continuity specified at the opposite in case that both continuities cannot be kept.
  • Create another matching constraint between the opposite end point or edge and the other target to manage the wanted continuity at the opposite with the same priority.
See also Mean Surface Solver option in Me > Preferences > App Preferences > 3D Modeling > Styling > FreeStyle Shape Design, General tab, Matching Constraint command options section.

Options

Inside
Projects the boundary on the target surface. On the target surface is displayed a preview of the edge position.
This option is automatically cleared if an edge is selected as target element or Partly option is selected.
On basic geometry
Matches curves or surfaces with the underlying geometry, i. e. considering the trimmed elements.
Diffusion
Modifies the maximum number of control points/rows, otherwise only control points/rows directly involved by the continuity chosen with the target are modified.
Condition before match is applied

G0 match without diffusion

Only the first control point row is moved.
G0 match with diffusion

Multiple control point rows are moved to optimize the control point distribution.
Adapt
Adopts the order of the target edge from the source.
Important: Only applicable when the target element is an isoparametric edge of its support surface.
Display deformation distance

Displays the maximum deviation value and its position between the original surface and the modified surface in the work area. The original mesh before the modification is also displayed.

You need to right-click the arrow of the variant display and select Reset Delta Reference to reset the reference, while using the command. The existing position of the surface is set as new reference. The reference mesh and the maximum deformation distance are computed with respect to the new reference.

Auto Apply
Refreshes the constraint each time you modify an option.
No Highlight Representations
Deactivates the highlight on the selected elements to avoid conflicts with the display of other entities such as control points.

Support

Defines the direction in which the control points are projected.

Along direction
Cleared: Moves the control points along the local normal of the target element.
Selected: The movement of control points depends on the propagation mode selected. The following modes are available which define the projection direction:
Along View
The direction is along the view direction. The control points move along the depth of the viewpoint. Rotate the part to see the control point movement.
User Line/Plane
The direction is along the selected line or normal to the selected plane.
The Robot option is available only with this mode. Right-click the Robot selection field and select the axis or plane. Using the contextual command you can create the required element. If Robot is selected, you can set this direction by manipulating the Robot in 3D.
Along Source
Projects the control points for G1/G2 along the normal of the source.
If Inside option is selected, the edge of the surface to be modified (the G0 row) is projected orthogonally on the target surface.

Modification Ratio

Specifies a ratio for displaying an intermediate result between the original and last applied status. It helps to control the final result with the best possible solution between all the constraints modifying the particular surface.

Minimum and maximum values in the Deviation section are updated dynamically when moving the slider.

Once you exit the Matching Constraint command with certain modification ratio, the next update of the constraint ignores the earlier specified ratio.

Variants

You can save option settings in variants to quickly and simultaneously switch in one step to the settings saved in a variant. This lets you create similar or different matching constraints from different input sets.

Note:
  • The variants are saved in temporary files in the CATSettings directory and not with the data hierarchy.
  • You cannot save push button settings like Adapt and Invert in variants.
Variant list
Lists all saved variants.
Creates a variant in which the current option settings are saved.
Deletes the current variant.
Saves the current variant.

Deviation

If selected, displays the Min Values and Max Values according to the orders of continuity after clicking Apply or OK.

G0
Distance - absolute.
G1
Angle between the tangents or normals - absolute.
G2
Radius error - relative.
Notes:
  • The values are not displayed in the work area.
  • The deviation is computed from the last modified source element. As a consequence, when clicking Apply more than one time, another deviation result is displayed each time.
  • You can use the Exact option to obtain a constant result.