Lesson 7 - Selection and Modification

Existing components can be selected and modified. Selection and modification not only applies to components as a whole. It is also possible to select and modify parts of components. This is mainly controlled via points -- the so called control points. This lesson describes how to select and modify drawing components and parts of them.

7.1 Selection

CADEMIA offers a variety of selection commands and input possibilities.

7.1.1 Components

In order to select a component as a whole use one of the commands below:

Pick a single component: Run the command PickNear by clicking the left mouse button on a single component. The identified component will be selected and unselected alternately.
Use a pick box: Run the command SelectByPick or UnselectByPick to use a pick box that intersects components to select or unselect.

In order to select or unselect components that are completely inside a pick box use the commands SelectByPickInside or UnselectByPickInside respectively.
All components: In order to select or unselect all drawing components run the command SelectAll or UnselectAll respectively.

7.1.2 Control points

A component has different kinds of control points:

Point: Points represent manipulation items, e.g. control points of a bezier curve (see path component).
Vertex: Vertices are the start and end points of a component's or a segment's geometric shape.
Segment: Segment points are used to identify a single segment of a path component.

The figure below illustrates the different point of control points: Vertices red, points black and segment points blue.

In order to select a control point you can run one of commands described below. Selected control points appear filled like in the figure presented above.

Pick a single control point: Once a component is selected as a whole run the command PickNear by clicking the left mouse button on the point. The identified control point will be selected or unselected alternately.
Use a pick box: In order to select control points that are inside a pick box run the command SelectPoints. Filters support you when selecting vertices only, points only, segment points only or any kind of points.

7.2 Modification

Components and parts of them have to be selected in order to manipulate them. Once selected the component's geometric shape, its attributes and other features can be modified.

7.2.1 Geometry

CADEMIA offers several commands for modifying the geometry of existing components. After selecting the components, control points or segments run one of the commands described below.

Translate: Moves the component or selected parts about a specified vector. Analogous, components can be copied via the command CopyTranslate. The command TranslateByMouseDrag utilizes left mouse button dragging when translating components or parts of it.
Rotate: Rotates the component or selected parts about a specified point by an angle. Analogous, components can be copied via the command CopyRotate.
Scale: Scales the component or selected parts about a specified point and a scale factor. Analogous, components can be copied via the command CopyScale.
Mirror: Mirrors the component or selected parts at a specified axis or line. Analogous, components can be copied via the command CopyMirror.

Another kind of modification is the splitting or type changing of an existing path segment.

SplitSegment: Splits the selected segment resulting in two coincident segments of the same type.
SetSegmentType: Changes the type of the selected segment to line, quad, cubic or arc (see path component).

7.2.2 Attributes and features

Once components are selected their attributes (see Graphical attributes section) and other features can be modified.

Attributes: In order to modify component attributes use the commands

ModLineWidth, ModLinePattern, ModDrawPaint, ModFillPaint, ModFontFamily, ModTextSize, ModAttByLayer (set component's attributes according to its layer) or
make use of the list boxes in the Toolbar and select a different list item.

Features: In order to modify component features run the command ChangeFeatures. A dialog for altering feature values will show up. All component attributes are represented as features.

7.3 Exercise

Draw the shapes presented below. Natural unit is [cm], drawing scale is 1:1, dimensioning unit is [cm].
Use these shapes in order to create the construction detail shown in the figure below. Make use of proper selection, modification and copying commands.