底图模块

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Introduction

简介

您可以利用底图工作台来绘制简单的2D对象,再利用其提供的其他工具来修改这些对象。此工作台提供了工具来定义工作平面、网格。另外,还有一个snapping系统可助您精确地控制几何体的位置。

用户创建的2D对象能以类似于Inkscape或Autocad中的方式用于通用绘图。这些2D图形也可用作零件工作台建筑工作台等其他工作台所创3D对象的基本组件。另外,也可以将底图对象转换至构图工作台,这意味着能够在零件设计工作台中利用这些图形来创建实体。

FreeCAD是一款以3D建模为主的应用软件,这使它的2D工具并非如其他绘图程序那样高级。如果您的主要目的是复杂的2D绘图与处理DXF文件,并不是3D建模,那么不妨考虑一款关于技术制图的专用软件,例如LibreCAD, QCad, TurboCad以及其他类似程序。

Draft Workbench Example

绘制对象

下面来介绍一些用于创建对象的工具。

Annotation objects

修改对象

以下这些工具用来修改已存在的对象。这写工具处理的是用户选定的对象,如果没有选择待处理对象,系统会提醒你选择一个。

许多工具(移动, 旋转, 阵列等)也可用于处理实体对象(零件, 零件设计, 建筑等)。

  • Join: joins lines together into a single wire.
  • Split: splits a wire into two at a point.
  • Upgrade: upgrades objects into a higher-level object.
  • Downgrade: downgrades objects into lower-level objects.
  • Shape 2D View: creates a 2D object which is a flattened 2D view of a 3D object.

Draft Tray

The Draft Tray allows selecting the working plane, defining style settings, toggling construction mode, and specifying the active layer or group.

Its tools are also available in the Draft → Utilities menu:

Draft annotation scale widget

With the Draft annotation scale widget the Draft annotation scale can be specified. introduced in version 0.19

Draft snap widget

The Draft snap widget can be used as an alternative for the Draft Snap toolbar. introduced in version 0.19

Draft Snap toolbar

The Draft Snap toolbar allows selecting the active snap options. The buttons belonging to active options stay depressed. For general information about snapping see: Draft Snap.

  • Toggle snap: toggles object snapping globally on or off.
  • Endpoint: snaps to the endpoints of line, arc and spline segments.
  • Midpoint: snaps to the middle point of line and arc segments.
  • Center: snaps to the center point of circles, arcs and faces, WP proxies and Building parts
  • Angle: snaps to the special cardinal points of circles and arcs, at 45° and 90°.
  • Intersection: snaps to the intersection of two line or arc segments. Hover the mouse over the two desired objects to activate their intersection snaps.
  • Perpendicular: on line and arc segments, snaps perpendicularly to the latest point.
  • Extension: snaps on an imaginary line that extends beyond the endpoints of line segments. Hover the mouse over the desired object to activate its extension snap.
  • Parallel: snaps on an imaginary line parallel to a line segment. Hover the mouse over the desired object to activate its parallel snap.
  • Special: snaps on special points defined by the object.
  • Near: snaps to the closest point or edge on the nearest object.
  • Ortho: snaps on imaginary lines that cross the last point, and extend at 0°, 45° and 90°.
  • Grid: snaps to the intersections of the grid lines, if the grid is visible.
  • Working plane: always places the snapped point on the current working plane, even if you snap to a point outside that working plane.
  • Dimensions: shows temporary X and Y dimensions while snapping.
  • Toggle grid: toggles the visibility of the grid on or off.

实用工具

Additional tools

其他工具可从Draft → Utilities菜单处找到。或者右击当前的环境菜单(context menu),具体可用工具取决于当前所选对象。

其他功能

Tree view context menu

The following additional options are available in the Tree view context menu:

Selection options

If there is a selection the context menu contains one additional sub-menu:

  • Utilities: a subset of the tools available in the main Draft Utilities menu.

Wire options

For a Draft Wire, Draft BSpline, Draft CubicBezCurve and Draft BezCurve this additional option is available:

  • Flatten this wire: flattens the wire based on its internal geometry. This option currently does not work properly.

Layer container options

For a Draft LayerContainer these additional options are available:

  • Merge layer duplicates: this option currently does not work.

Layer options

For a Draft Layer these additional options are available:

Working plane proxy options

For a Draft WorkingPlaneProxy these additional options are available:

  • Write objects state: updates the visibility state of objects stored in the working plane proxy.

3D view context menu

The following additional options are available in the 3D view context menu:

No-selection options

If there is no selection the context menu contains one additional sub-menu:

  • Utilities: a subset of the tools available in the main Draft Utilities menu.

Selection options

If there is a selection the context menu contains two additional sub-menus:

Obsolete tools

These commands are obsolete but still available:

These 3D view context menu options are still available when the Draft Wire, Draft BSpline, Draft CubicBezCurve or Draft BezCurve command is active but will be removed in the near future:

首选项

文件格式

底图模块为FreeCAD提供了下列格式文件的导出、导出服务:

Install importers

Unit tests

See also: Test Workbench.

To run the unit tests of the workbench execute the following from the operating system terminal.

freecad -t TestDraft

脚本

借助Draft API即可在Python控制台中使用各种底图工具。

The workbench includes a module to create samples of all objects in a new document. introduced in version 0.19

Use this to test that all objects are produced correctly.

import drafttests.draft_test_objects as dto
doc = dto.create_test_file()

Inspecting the code of this module is useful to understand how to use the programming interface.

$INSTALLDIR/Mod/Draft/drafttests/draft_test_objects.py

Where $INSTALLDIR is the toplevel directory where the software was installed; for example, in Linux it may be /usr/share/freecad.

Test objects for the Draft Workbench.