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Every drawing object has special defined characteristics called Properties, which govern appearance, location and other factors important to that object. Most entities have basic properties such as color, layer, linetype and thickness. Controlling the appearance and actions of an object requires a thorough understanding of the object's properties.
The PROPERTIES command displays the Properties Window, shown at the right. Type [Props] at the command line or select the 
Properties button on the Standard toolbar to display the Properties Window. If there are no entities selected the current drawing properties settings are displayed. These include view settings, USC icon settings and display area coordiantes, and settings controlling the properties that will be attached to new entities, such as layer, linetype, and color, and plot style settings.
If a drawing object is selected, the Properties Window lists that object's properties on the left and the current property settings or values on the right. If several entities are selected, only common properties are listed, and those which have the same properties, but different property settings have blank settings in the list. The Properties Window also provides ready calculations on drawing entities such as circumference, area and length, depending on the object. These properties are merely informational and cannot be changed. They appear greyed out.
Properties can be changed in the Properties Window by selecting a property value. Properties which have limited choices provide a pull-down selection set. Change the value by choosing a new value from the pull-down list. Properties with larger choices, like coordinate values, can be changed by typing in a new value. The Properties Window is not only a powerful information tool, but is also a powerful editing tool. To line up several entities horizontally, select them all and give them the same X coordinate.
Right mouse click on the Properties Window border to allow the Properties Window to dock or not, close the window, undo changes, or toggle the Descriptions box at the bottom off or on.
The current active property settings for Color, Layer, Linetype, Linetype scale, Lineweight and Thickness, as they appear in the Properties Window and the Object Properties toolbar when there are no entities selected, are automatically set for new entities added to the drawing. The current active property settings can be changed via the Properties Window or by the pull-down menus on the Object Properties toolbar.
LAYER is perhaps the most important property. All entities are placed on a layer. Think of the layer as a clear sheet that can be added or removed from a drawing as necessary. Layers have a more import role. Many of the most basic properties default to "Bylayer", allowing the layer definition to determine Color, Linetype, Lineweight and Plotstyle, as well as whether the object will appear in the final print. Details below.
Every object has a COLOR property. Even if the final print or plot is intended to be produced in black and white, color helps visual identification of separate groups of drawing entities. Since most entities should be drawn with color set to "Bylayer", color is the most obvious clue as to the object's layer.
Every line, polyline, arc or circle has a LINETYPE. By changing the Linetype property to some linetype other than Continuous or ByLayer, such as Dashed or Dot, the object will appear to be broken up into dashes or dots. The object is still edited as a single object but the appearance of the line is changed. There are many basic linetypes available with AutoCAD, but, if you want more, you can create your own.
Linetypes must be "Loaded" into the drawing. Type [LT] or select Other… from the Linetype Control pull-down box on the Object Properties toolbar to bring up the Linetype Manager window. Select Load… to bring up the Load or Reload Linetypes window and select a linetype to load. The chosen linetype is now a part of the drawing, which can be selected in the Linetype Control pull-down box.
The Polyline command deals with Linetypes in different ways depending on the system settings. Generally you will want the dashes and dots to continue smoothly through the vertices along the polyline. The system variable PLINEGEN sets the default for all new polylines. Set Plinegen ON <1> to generate a continuous linetype pattern through the polyline vertices. When Plinegen is OFF <0> the pattern will start and stop at each vertex. In polylines with short segments or tight curves this setting may cause the pattern to dissappear altogether, leaving a continuous line instead. Set the the individual polyline pattern with the Linetype generation property in the Properties Window.
LINETYPE SCALE will scale the size of the linetype pattern up or down for a specified object. As a rule, I prefer to leave the individual linetype scales at 1.0, using seperate linetypes for larger and smaller size patterns. Scale all the linetypes in the drawing at once with the LTSCALE command.
New with AutoCAD 2000, LINEWEIGHT sets the line width for the object. It is now considered preferrable to set line width as a decimal of a millimeter, as with technical pens. A very fine line would be 0.02mm to 0.05mm. A lineweight of 0.70mm would be very heavy. The Lineweight (LWT) toggle makes the lineweights visible on screen, but does not effect the printed appearance. If the display is taking too long to refresh, turn this setting off.
THICKNESS has nothing to do with lineweight. Thickness sets a line height in the Z direction. It has no significance for 2d drafting. I will cover thickness in the section on 3d.
Imported from other graphics programs, DISPLAY ORDER is new to AutoCAD 2000. Display order allows the selection order to be changed for stacked entities. An object that is constantly grabbed by mistake can be sent to the back of the selection stack, making it less likely to be selected. This is a logical ordering and has nothing to do with its location on the Z coordinate.
All entities that are located in the drawing space (geometry) have Geometry properties. A circle has a center point with X,Y,Z coordinates and a radius, whereas a line has endpoints, angle and length. Raster images and complex entities made up of many primitives (Blocks and External References) have Scale.
Text has Geometry properties and Text properties such as justification, text style and text height. Raster images have special properties for Image Adjustment and Miscellaneous properties such as the file path and name and a transparency toggle. Dimensions have the most complex set of properties and are much better handled by the Dimension Style Manager.
Since the geometry properties (coordiantes, length, radius…) are completely different between a line and circle there will be no geometry properties displayed in the Properties Window when a circle and line are selected at the same time. If the two reside on different layers, the layer property will be displayed, (they both have a layer property), but the Layer property setting will be blank both in the Properties Window and the Object Properties toolbar. The Layer property setting can still be reset, but it will be reset for all entities selected.
Getting familiar with the properties of the various drawing entities is an excellent way to get a better understanding of those entities and the range of possibilities they afford. When a new property pops up, the help file for that object should explain the property.
Large numbers of drawing elements make the individual management of drawing properties difficult or impossible. LAYERS simplify the process by establishing groups of elements with preset property settings in the most important property classes (Color, Linetype, Lineweight and Plot Style). Layers have several other management functions. Layers can be shut Off or Frozen, temporarily removing them from the active drawing. Layers can be Locked so that its entities cannot be changed. And layers can be removed from plotting even while they remain visible in the drawing.
By setting the general properties for Color, Linetype, Lineweight, and Plot Style to "ByLayer", the properties for each drawing object are set by Layer property settings. These settings are set in the Layer Properties Manager, shown above, and accessed by the LAYER command or 
the Layers button on the Object Properties toolbar. By drawing all of the walls for the first act on a single layer, the wall properties can be managed as a unit ensuring consistency and ready adaptability. The walls for act two, placed on a seperate layer, are managed seperately.
Always draw with Color, Linetype, Lineweight and Plot style properties set to "ByLayer".
CADvise:
As the number of objects and the complexity of the drawing increases, the drawing may become confusing or difficult to seperate, and the drawing size can slow the screen regeneration. Through the Layer Properties Manager or the Layer pull-down menu on the Object Properties toolbar, you can turn Off or Freeze layers individually. Any layer that is interferring with the current drawing process can be temporarily eliminated.
In the Layer Properties Manager the layer "P-Act2-Furn" which is turned Off has the grey light bulb in the "On" column to indicate its current state. This layer stays in active memory, meaning it will regenerate with other active elements, but will not print or display. Turning this layer [On] will only require a screen [Redraw], which is faster than a screen Regeneration. The layer "S-Act1-Htch" which is Frozen is indicated by a snowflake in the "Freeze in all VP" column. This layer is removed from active memory making screen Regeneration faster, but will require a full Regeneration when it is turned back on.
If it's coming back soon, turn it Off. If it's going away for a long while, Freeze it.
Notice that there are two Freeze options greyed out below, and their columns are not displayed: "Freeze in active viewport" and "Freeze in new viewports". These two options are only active when inside of viewports and will be covered in the Layout section.
Using the Freeze/Thaw controls, the drafter can align elements that will never be plotted on the same sheet. Put all of the act one walls on one layer called "S-Act1-Wall". Put all of the act two walls on one layer called "S-Act2-Wall". Freeze one and Thaw the other. To see the other choice, reverse the Freeze/Thaw operation. When both layers are Thawed, the lineup of the two sets of walls can be checked.
Move large or complex elements onto separate layers. Freezing those layers will speed up regeneration. Area fill because of the number of drawing objects involved is time consuming for the memory to manipulate. Place area fill ("hatching") on a separate layer or layers so the layer can be frozen until ready to print. Additionally, you can give the hatch layer a separate color and lineweight from the walls. Other layers with many objects might include the audience seating, mechanical details, and layers with a large amount of lettering, such as a "notes" layer.
Now suppose that you want to have act one elements visible while you are drawing act two, but you do not want any of the act one objects changed by accident. LOCK the act one layers by clicking on the paddle lock icon in the "Lock" column of the Layer Properties Manager. An open lock is unlocked, while the closed lock, as in the "P-Act1-Furn" layer above, indicates that the layer is locked. The objects are visible on screen, will plot normally, but cannot be edited in the drawing window.
Finally, notice that the "P-Act1-Musc" layer in the Layer Properties Manager view above has a red circle with a slash over the printer icon in the "Plot" column. This indicates that the "P-Act1-Musc" layer is currently in a No-Plot mode. It will appear normally on screen, can be edited as usual, but the contents of this layer will not appear in printed or plotted output.
When plotting in black and white, specific colors or layers can be plotted in black on white (line art), or shades of grey (grey scale). This is set with Plot Style Tables and attached in the Plot style settings in the Properties Window or in the Layer Properties Manager. I'll save that discussion for the section on Plotting.
For all releases prior to AutoCAD 2000, color plays a crucial role in black and white plotting. When plotting, each drawing color number is matched to a plotter pen or virtual pen. Each plotter pen (for very old plotters) or virtual pen can be a different color and/or line weight (line width). Therefore the actual plotted Color, Lineweight and Linetype can be set separately for each drawing color. Separating drawing objects into different colors allows them to be matched as a class to appropriate line weight or pen color. Of course, pen color is only available on color plotters.
The number of colors that you can see on your screen and the actual shade of those colors depends upon you graphics card and your monitor. Because of this, the exact same drawing may appear in very different colors on two different computer systems. This is not usually important. Colors one thru seven have been assigned standard values (red, yellow, green, cyan, blue, magenta and white) to facilitate exchange between computer systems. The more significant assignments are the pen settings, which have not been standardized, see Appendix D for my personal standards.
AutoCAD Reference: Standard ColorsPen 1. Red Pen 2. Yellow Pen 3. Green Pen 4. Cyan Pen 5. Blue Pen 6. Magenta Pen 7. White |
Consistency is important when plotting lineweights by color definition. I never change my pen settings. By looking at the colors on any of my drawings I can visualize the final product. I already know the lineweight of the colors I see.
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