Commands for drawing Line Elements

Commands for drawing Line Elements.

1. Drawing Line
2. Line Properties
3. Drawing 2D PolyLine
4. PolyLine Properties
5. Drawing MultiLine
6. MultiLine Properties
7. Drawing Spline
8. Spline Properites
9. PolyLine Edit

In AutoCAD, we can draw 4 lines:

Pict. 1 Lines

A) Line;   B) 2D PolyLine; C)  MultiLine; D) Spline

As we can see, Line is a straight segment. A PolyLine is connected sequence of segments. MultiLine is connected sequence of segments paralleled lines. Spline creates curves called nonuniforme rational B-Splines(NURBS), referred to as Spline for simplicity.

1. Drawing Line

To start draw Line either press button     on tools panel, or run in command line:  

Command: _LINE

Specify first point:

Specify next point or [Undo]:

Specify next point or [Undo]:

To set length or angle of line just type-in “Dynamic Input” window,  length of the line (length set in units, that yours drawing configured) and rotate line.

Pict.2 Dynamic input

Pict.3 Line length and angle

If we want to draw many lines we don’t need every time press on  button or run command LINE, AutoCAD automatically asks you about next point.    

Specify next point or [Undo]:  

Specify next point or [Undo]:

If we draw more than 2 lines, program asks to close figure or specify next point.

Specify next point or [Close/Undo]: C

AutoCAD draws line from the last point to first point.

2. Line Properties

To configure Line properties we can either before or after drawing. Every line has standard properties:  

• Layer
• Line Color;
• Line type;
• Linetype scale;
• Lineweight;

To view Line properties select line and  type-in command:

Command: _PROPERTIES

Picture 4. Line Properties

In “Properties” window we can set: Color, Layer, Linetype, Linetype scale, Lineweight, Thickness.

Color is a simple property, and don’t need to tell about it.  Most important properties are Linetype, Linetype scale and Lineweight.

Linetype set  type of the line, like on picture 5.   

Pict. 5 Line types

To set line type in GUI mode select line type in LineType menu. For more properties choose   “Line Type Control/Other”  or run command:

Command: _LINETYPE

Pict. 6 Linetype Manager

In this window we can select linetype, load  new linetypes, set scale factor, delete linetype in current drawing.  If linetype that we decide to delete uses in current drawing we have to change all used linetypes  to other types.  

Linetype Scale

All  line types are created in their native scale.  When we will draw lines in their native scale in drawing their will looks like continuous line or not correct scale like on picture 7.

Pict.7 Linetypes. Not correct scale factor

Before drawing set correct scale factor.

To run Linetype manger in text mode run command :

Command:-LINETYPE

-LINETYPE

Current line type:  "ByLayer"

Enter an option [?/Create/Load/Set]: Set   // choosing Set mode

Specify linetype name or [?] <ByLayer>: ?

Enter linetype name(s) to list <*>: *  // show all linetypes

ByLayer, ByBlock, or one of these loaded linetypes:

     Name          Description

---------------- ------------------

"ACAD_ISO03W100"  ISO dash space __    __    __    __    __    __

"ACAD_ISO04W100"  ISO long-dash dot ____ . ____ . ____ . ____ . _

"BATTING"        Batting SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS

"Continuous"     Solid line

"Пластиковый короб"    ----П----П----

Enter an option [?/Create/Load/Set]:

Resuming -LINETYPE command.

Enter an option [?/Create/Load/Set]: S

Specify linetype name or [?] <ByLayer>: Пластиковый короб

Enter an option [?/Create/Load/Set]:

Automatic save to C:\Users\Игорь\AppData\Local\Temp\Drawing1_1_1_8323.sv$ ...

Command: -LINETYPE

Current line type:  "Пластиковый короб"

. . .

Lineweigth is property that responded for line thickness on paper (pdf, jpg or other printed format).

Pict.8 Linewigth

As we see on picture 8  lineweight 0.00 mm and 0.2 mm on the screen are identical, but on paper this lines will have a different look.  

Every AutoCAD drawing has default lineweight, to configure it run command:

Command: _LWEIGHT

Pict.9 Lineweigth Settings

In this window we set default lineweight and set units for listing.  

If we want set properties for all lines in one place press button or  run  command:

Command: _LAYER

Pict. 10 Layer Properties

After customizing the appearance of lines  set all spinners  to values “ByLayer”.

3. Drawing 2D PolyLine

A 2D PolyLine is a connected sequence of segments created as a single planar object. We can create straight line segments, arc segments, or a combination of the two.

To start drawing Poly Line press button   , in tools panel, or run command :

Command: _PLINE

Specify start point:

Current line-width is 0.0000

Specify next point or [Arc/Halfwidth/Length/Undo/Width]:

Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]: Arc

Specify endpoint of arc or

[Angle/CEnter/CLose/Direction/Halfwidth/Line/Radius/Second pt/Undo/Width]:

Specify endpoint of arc or

[Angle/CEnter/CLose/Direction/Halfwidth/Line/Radius/Second pt/Undo/Width]: Line

Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]:

Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]:

Pict. 11 2D PolyLine

If we want to draw arc element choose   Arc property in command line, or press choose Arc in context menu. PolyLine has control vertexes. You can move vertexes, add new vertex or stretch vertex, also we can convert segment  to Arc or line element.

Pict.12 Convert segment to Arc

4. PolyLine Properties

Pict. 13 PolyLine properties

PolyLine properties consists of Line properties and own properties.  Own properties:

• Vertex;
• Width;
• Elevation;
• Area;
• Closed;

PolyLine width – Specifies the starting and ending width of the next line segment.

Each segment have start and end vertex, all segments are has custom properties that we can configure.

Pict.14 PolyLine segment properties

As we see all segments have their own properties. On picture 13 segment that starts from vertex 4, has “Start segment width” – 5 mm,  “End segment width” – 100 mm.  To set Global width, run command:

Command: _PLINE

Specify start point:

Current line-width is 20.0000

Specify next point or [Arc/Halfwidth/Length/Undo/Width]: Width

Specify starting width <20.0000>: 50

Specify ending width <50.0000>:

Specify next point or [Arc/Halfwidth/Length/Undo/Width]:

Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]:

Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]:

Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]:

Pict. 15. PolyLine Global width 50

Width will be 50 mm while we do not set new value.    

Each vertex has a property “Elevation” that responsible for displacement along the axis Z. Keep  Elevation = 0;

Also polyline has not editable property  “Area” in mm^, “Length” in mm.

If option “Closed”  = YES  AutoCAD automatically closes the polyline by joining the last segment with the first segment.

5. Drawing MultiLine

Creates multiple parallel lines.

To start draw multiple line  press button

 

or run command prompt:

Command: _MLINE

Current settings: Justification = Top, Scale = 20.00, Style = STANDARD

Specify start point or [Justification/Scale/STyle]:

Specify next point:

Specify next point or [Undo]:

Specify next point or [Close/Undo]:

Specify next point or [Close/Undo]:

Pict. 16 MultiLine

6. MultiLine Properties

MultiLine properties  consists of Line properties and own properties.  Own  properties of Multiline:

• Justification;
• Scale;
• Style;

Justification determines how the multiline is drawn between the points you specify.

Top

Zero

Bottom

Command: MLINE

Current settings: Justification = Top, Scale = 20.00, Style = STANDARD

Specify start point or [Justification/Scale/STyle]:  J

Enter justification type [Top/Zero/Bottom] <top>:  Z

Current settings: Justification = Zero, Scale = 20.00, Style = STANDARD

Specify start point or [Justification/Scale/STyle]:

Pict. 17 MultiLine Justification
A) Bottom; B) Zero; C) Top

Scale  sets  the width of the multiline. This scale does not affect linetype scale.

To set scale 100  run  comand prompt:  

Command: _MLINE

Current settings: Justification = Zero, Scale = 20.00, Style = STANDARD

Specify start point or [Justification/Scale/STyle]:  S

Enter mline scale <20.00>:  100

Current settings: Justification = Zero, Scale = 100.00, Style = STANDARD

Specify start point or [Justification/Scale/STyle]:

Specify next point:

Specify next point or [Undo]:

Specify next point or [Close/Undo]:

Specify next point or [Close/Undo]:

Pict. 18 MultiLine Scale=100 Justification = Zero

Style  specifies a style to use for the multiline.

7. Drawing Spline

A spline is a smooth curve that passes through or near a set of points that influence the shape of the curve.

We can create or edit spline using either control vertices, or fit point.  

To create spline line either press button on tools panel, or run command:

Command:_SPLINE

Current settings: Method=Fit   Knots=Chord

Specify first point or [Method/Knots/Object]:

Enter next point or [start Tangency/toLerance]:

Enter next point or [end Tangency/toLerance/Undo]:

Enter next point or [end Tangency/toLerance/Undo/Close]:

Enter next point or [end Tangency/toLerance/Undo/Close]:

Enter next point or [end Tangency/toLerance/Undo/Close]:

Pict. 19  Spline

8. Spline Properties

This material taks from Autodesk Help.

Method:

Controls whether the spline is created with fit points or with control vertices. (SPLMETHOD system variable)

Fit

Creates a degree 3 (cubic) B-spline by specifying fit points that the spline must pass through. When the tolerance value is greater than 0, the spline must be within the specified tolerance distance from each point.

Control Vertices (CV)

Creates a spline by specifying control vertices. Use this method to create splines of degree 1 (linear), degree 2 (quadratic), degree 3 (cubic), and so on up to degree 10. Adjusting the shape of a spline by moving control vertices often provides better results than moving fit points.

Object

Converts 2D or 3D quadratic or cubic spline-fit polylines to equivalent splines. The original polyline is retained or discarded depending on the setting of the DELOBJ system variable.

Knots

Specifies the knot parameterization, one of several computational methods that determines how the component curves between successive fit points within a spline are blended. (SPLKNOTS system variable)

• Chord. ( Chord-Length method) Spaces the knots connecting each component curve to be proportional to the distances between each associated pair of fit points. An example is the green curve in the illustration.
• Square root. (Centripetal method) Spaces the knots connecting each component curve to be proportional to the square root of the distance between each associated pair of fit points. This method usually produces “gentler” curves.
• Uniform. (Equidistant method). Spaces the knots of each component curve to be equal, regardless of the spacing of the fit points. This method often produces curves that overshoot the fit points.

Start Tangency

Specifies a tangent condition on the starting point of the spline.

End Tangency

Specifies a tangent condition on the ending point of the spline.

Tolerance

Specifies the distance by which the spline is allowed to deviate from the specified fit points. A tolerance value of 0 requires the resulting spline to pass directly through the fit points. The tolerance value applies to all fit points except the starting and ending fit points, which always have a tolerance of 0.

Degree

Sets the polynomial degree of the resulting spline. Use this option to create splines of degree 1 (linear), degree 2 (quadratic), degree 3 (cubic), and so on up to degree 10.

9. Polyline Edit

PolyLine edit  allows  converting lines and arc and spline to polylines object, join 2D polyline , converting 2D polyline to spline curve.   

If selected object not polyline (line, arc, splie) the following prompt is displayed:

Command: PEDIT

Select polyline or [Multiple]:

Object selected is not a polyline

Do you want to turn it into one? <Y>

Enter an option [Close/Join/Width/Edit vertex/Fit/Spline/Decurve/Ltype gen/Reverse/Undo]:

If we enter Y, Autocad converted all selected objects to the polyline segments.

If object is spline object, the following prompt asks you to enter precision:

Command:_PEDIT

Select polyline or [Multiple]:

Object selected is not a polyline

Do you want to turn it into one? <Y>

Specify a precision <10>:

Enter an option [Close/Join/Width/Edit vertex/Fit/Spline/Decurve/Ltype gen/Reverse/Undo]:

Now we have a PolyLine objects.  We can edit them.

Command: _PEDIT

Select polyline or [Multiple]:

Enter an option [Close/Join/Width/Edit vertex/Fit/Spline/Decurve/Ltype gen/Reverse/Undo]:

Options of the PEDIT:

Close -  draw segment from last segment  to first segment of the polyline.

Join – make join 2 or more polyline into one object.

Width – sets width of the selected polylines

Edit vertex – edit vertex properties;

 Fit - to create an arc-fit polyline, a smooth curve consisting of arcs joining each pair of vertices

Spline – converted to create an approximation of a spline.

Decurve -  convert all segments into straight lines;

Ltype gen - to generate the linetype in a continuous pattern through the vertices of the polyline;

Reverse -  to reverse the order of vertices of the polyline;

Undo -  to reverse actions back to the start of PEDIT;