# Description

X-Topology Curves are used to define the wire framework from which X-Topology sufaces are generated. The underlying mathematics of the curve is based upon the BSpline definition but, through the use of constraints, the curve can interpolate its control points, form straight sections and blends. The curve can dynamically snap to other X-Topology curves, updating as the parent curve is changed. The tangent of curve through a control point attached to another curve may be controlled by its parent.

# Creation

Menu: Create -> X-Topology Curve

Interactively create a X-Topology curve by Left-Clicking to create the points of the control polygon. The initial orientation of curve will be defined on the Default Edit Plane.

See Also:-

# Interactive Editing

Edit mode is entered by pressing F2 displaying the control polygon of the curve. The control points of the entity are selected and edited using the PolyCAD standard manipulation techniques. One point to note is that when adding points, points constraints will be automatically added and removed so that the curve definition remains consistent.

See Also

# Entity Attributes Panel

X-Topology Curve Attributes Panel

# Edit Menu

- Insert into Surface
- Remove from Surface
- Override Point Tangent Condition
- Knuckle Point
- Interpolate Point
- Tangent Through Point
- Straight Segment
- Blended Segment
- Polyline Curve
- Cubic Spline Curve
- Surface Tangent Constraint
- Cubic Spline Knot Vector based on Chord Length
- Force Curve to be Surface Boundary
- Unlink Point
- Reverse Point Order
- Convert Cubic Spline to Interpolation Points
- Convert to BSpline Curve
- Convert to Polyline Curve

# Multi-Select Menu

- Create XTSurface Group
- Insert into Surface
- Remove From Surface
- Force Curves to be Surface Boundary
- Cubic Spline Knot Vector based on Chord Length
- Knuckle Surface Tangent Constraint
- Convert XTCurves to BSplines
- Convert XTCurves to Polylines

# Display Options

# Short Cuts

- A - Add point to representation while editing
- Del - Delete points from representation while editing
- F2 - Edit
- F11 - Show Attributes

# File Format

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# Import / Export

Format | Import | Export |
---|---|---|

AutoCAD DXF | Yes as BSpline or Polyline | |

Initial Graphics Exchange Spec. (IGES) | Yes as BSpline | |

ACIS (Autodeck/Tribon/Aveva Marine Initial Design) | Yes as BSpline |

# Articles

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# References

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