Sketcher CreateEllipseByCenter/zh-cn: Difference between revisions
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[[Image:Sketcher_EllipseExample1.png|thumb|none|500px|绘制椭圆所选中的一系列点以带数字的黄色箭头表示。C为中点,a - 长半轴,b - 短半轴,F1、F2为焦点。]] |
[[Image:Sketcher_EllipseExample1.png|thumb|none|500px|绘制椭圆所选中的一系列点以带数字的黄色箭头表示。C为中点,a - 长半轴,b - 短半轴,F1、F2为焦点。]] |
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==如何使用== |
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* Invoke the command by clicking a toolbar button, picking the menu item, or by using keyboard shortcut (needs to be assigned first in [[Interface Customization]]). |
* Invoke the command by clicking a toolbar button, picking the menu item, or by using keyboard shortcut (needs to be assigned first in [[Interface Customization]]). |
Revision as of 08:32, 20 July 2019
Sketcher Create Ellipse by center |
Menu location |
---|
Sketch → Sketcher geometries → Create ellipse by center |
Workbenches |
Sketcher |
Default shortcut |
None |
Introduced in version |
0.15 |
See also |
Sketcher Ellipse by 3 Points, Sketcher Circle, Sketcher Arc of Ellipse |
描述
本工具会根据用户拾取的三个点:中点、长半轴点与短半轴点来绘制一个椭圆。 在开启此工具时,鼠标指针会变为一个附有红色椭圆图标的白色十字。同时还会将当前的指针坐标实时显现在侧。
如何使用
- Invoke the command by clicking a toolbar button, picking the menu item, or by using keyboard shortcut (needs to be assigned first in Interface Customization).
- First click in 3D view sets ellipse center. Second click sets the first radius and orientation of the ellipse. Third click sets the other radius (the distance from the line defined by first two clicks is the second radius).
- After the third click, the ellipse is created, together with a set of construction geometry aligned to it (major diameter, minor diameter, two foci). The construction geometry can be manually deleted if not needed, and recreated later. See Internal Alignment Constraint and Sketcher Show Hide Internal Geometry.
- Pressing ESC or clicking the right mouse button cancels the function.
Peculiarities
- Major and minor axes of ellipses are strict and cannot be swapped by resizing the ellipse. This is a consequence of the solver parametrization used (center (x,y), focus1 (x,y) and minor radius length (b)) and the same strict behavior of OpenCascade. The ellipse must be rotated to swap the axes.
- Ellipse can function as a circle when its major and minor diameter lines are deleted, and one of the foci is constrained to coincide with the center. But radius constraint won't work on such a circle.
- Moving the ellipse by edge is the same as moving ellipse's center.
Sketcher
- General: Create sketch, Edit sketch, Map sketch to face, Reorient sketch, Validate sketch, Merge sketches, Mirror sketch, Leave sketch, View sketch, View section, Toggle grid, Toggle snap, Configure rendering order, Stop operation
- Sketcher geometries: Point, Line, Arc, Arc by 3 points, Circle, Circle by 3 points, Ellipse, Ellipse by 3 points, Arc of ellipse, Arc of hyperbola, Arc of parabola, B-spline by control points, Periodic B-spline by control points, B-spline by knots, Periodic B-spline by knots, Polyline, Rectangle, Centered rectangle, Rounded rectangle, Triangle, Square, Pentagon, Hexagon, Heptagon, Octagon, Regular polygon, Slot, Fillet, Corner-preserving fillet, Trim, Extend, Split, External geometry, Carbon copy, Toggle construction geometry
- Sketcher constraints:
- Geometric constraints: Coincident, Point on object, Vertical, Horizontal, Parallel, Perpendicular, Tangent, Equal, Symmetric, Block
- Dimensional constraints: Lock, Horizontal distance, Vertical distance, Distance, Radius or weight, Diameter, Auto radius/diameter, Angle, Refraction (Snell's law)
- Constraint tools: Toggle driving/reference constraint, Activate/deactivate constraint
- Sketcher tools: Select unconstrained DoF, Select associated constraints, Select associated geometry, Select redundant constraints, Select conflicting constraints, Show/hide internal geometry, Select origin, Select horizontal axis, Select vertical axis, Symmetry, Clone, Copy, Move, Rectangular array, Remove axes alignment, 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, Show/hide B-spline control point weight, Convert geometry to B-spline, Increase B-spline degree, Decrease B-spline degree, Increase knot multiplicity, Decrease knot multiplicity, Insert knot, Join curves
- Sketcher virtual space: Switch virtual space
- Additional: Sketcher Dialog, Preferences, Sketcher scripting
User documentation
- Getting started
- Installation: Download, Windows, Linux, Mac, Additional components, Docker, AppImage, Ubuntu Snap
- Basics: About FreeCAD, Interface, Mouse navigation, Selection methods, Object name, Preferences, Workbenches, Document structure, Properties, Help FreeCAD, Donate
- Help: Tutorials, Video tutorials
- Workbenches: Std Base, Arch, Assembly, CAM, Draft, FEM, Inspection, Mesh, OpenSCAD, Part, PartDesign, Points, Reverse Engineering, Robot, Sketcher, Spreadsheet, Surface, TechDraw, Test Framework
- Hubs: User hub, Power users hub, Developer hub