Sketcher BSplineGradErhöhen
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| Menüeintrag |
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| Sketch → B-Spline-Werkzeuge → Grad des B-Splines erhöhen |
| Arbeitsbereich |
| Sketcher |
| Standardtastenkürzel |
| Keiner |
| Eingeführt in Version |
| 0.17 |
| Siehe auch |
| BSplineGrad, BSplineGradVerringern |
Beschreibung
Erhöht den Grad (Ordnung) der B-Spline-Kurve (Siehe die Seite B-Splines für weitere Informationen über B-splines).
Anwendung
- Eine Kante eines existierenden B-Splines auswählen.
- Die Schaltfläche
Grad des B-Splines erhöhen drücken.
Example
B-splines are basically a combination of Bézier curves (nicely explained in this and this video).
In this cubic B-spline (degree 3) there are 3 segments, meaning 3 curves are connected at 2 knots.
The degree is indicated by the number in the center. See 
Show/hide B-spline degree.
B-spline with degree 3 and 2 knots that each have multiplicity 1.
The outer segments each have 2 control points, the inner segment has none to ensure the knots have multiplicity 1. See this page for an explanation about multiplicity.
Increasing the degree to 4 will add control points without changing the shape of the B-spline:
Same B-spline where the degree was changed from 3 to 4. Note that the knot multiplicity has also increased.
From this result you cannot get back to the initial state of the B-spline by decreasing the degree. Some information is lost when the degree of a B-spline is changed. Decreasing the degree back to 3 leads to this:
Same B-spline where the degree was changed back from 4 to 3. Note that the knot multiplicity has increased again. Depending on the B-spline, the algorithm to decrease the degree may add a lot of knots to preserve the shape as has happened here.
Each segment now has 2 control points and each knot is coincident with an additional control point. The knots have C0 continuity so that the B-spline will get "corners" if you move a control point. The information of a higher continuity is therefore lost. See this page for an explanation about continuity.
(FIXME)
- Die Werkzeuge: Skizze erstellen, Skizze bearbeiten, Skizze verlassen, Skizze anzeigen, View section, Skizze einer Fläche zuordnen..., Reorient sketch, Skizze überprüfen, Skizzen zusammenführen, Skizze spiegeln
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- Dimensional constraints Sperren, Horizontaler Abstand, Vertikaler Abstand, Distanz festlegen, Radius festlegen, Winkel festlegen, Snell's Law, Umschalten auf steuernde Bemaßung,
- Sketcher tools Select solver DOFs, Close Shape, Connect Edges, Select Constraints, Select Origin, Select Vertical Axis, Select Horizontal Axis, Select Redundant Constraints, Select Conflicting Constraints, Select Elements Associated with constraints, Show/Hide internal geometry, Symmetry, Clone, Copy, Move, Rectangular Array, Delete All Geometry, Delete All Constraints
- Sketcher B-spline tools Show/Hide B-spline degree, Show/Hide B-spline control polygon, Show/Hide B-spline curvature comb, Show/Hide B-spline knot multiplicity, Convert Geometry to B-spline, Increase degree, Increase knot multiplicity, Decrease knot multiplicity
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