Center for the Study of Architecture (Archeology) If you really want yo see how complex Layer Names can become
What is a CAD Layer?
The common metaphor for a layer “clear plastic sheet” although initially helpful is overly simplistic tending to lodge in a drafter’s mind forever hampering a fuller understanding of layers.
The first thing to say about LAYERS is that “LAYERS” is not the best word to describe them. Forget layers as anything physical (transparent sheets and the like) and think instead of “LAYERNAME” as a LABEL for a list of object properties. One should think of “assigning” the property of LAYERNAME to objects rather than assigning objects to a layer. Although it is common to refer to drawing “ON” a layer, typically done by setting a layer to be the current layer and about “MOVING” objects from one layer to another in reality this is assigning a LAYERNAME oops! LABEL as a property of objects.
Each Layer or rather LAYERNAME (Properties List Label) has a number of user definable properties assigned to it such as color and line-type and may in addition may have any number of other implied properties assigned by association via the layer NAME or LABEL. Such implied properties may include the nature, function and location of objects within a project. Note that if OBJECT properties are assigned by BYOBJECT rather than BYLAYER (the commonly preferred option) neither the assigned LAYER properties nor the implied PROJECT properties are attached to OBJECTS but the OBECTS have associated properties by virtue of their LAYERNAME. (PHEW!)
Why create Layernames that imply properties to objects?
You may wonder why I have taken the trouble to re-write what you already knew. Layers are so important and a Standard is so critical that it is worth saying again. A complete project can be drawn coincident and then separated drawing by drawing (or function by function) by viewing and plotting appropriate layers.
Most Layer tutorials concentrate on how to use the program saying little about Layer Naming Standards or how to use layers effectively and rarely offer advice about using potentially faster keyboard commands rather than slow visually overwhelming layer manager dialogues so let me explain what MYCADLAYERS is and does.
What is MYCADLAYERS?
MYCADLAYERS is a custom Autolisp layer management program offering both a custom designed Layer Naming Standard and the means of automatic creation and management. (Custom designed Standard how can that be? you might ask.). MYCADLAYERS layernames a re simpler, shorter, more meaningful and easier to use than most layer standards yet comply with the principles of all major international standards.
MYCADLAYERS completely replaces normal CAD dialogue layer naming and management procedures, such as LMAN, dramatically reducing operator effort. How much? I'm not really sure because it is so long since I have needed to use slow and clumsy layer management dialogues but my guess is that for me MYCADLAYERS reduces the task to less than one quarter of the time required by conventional means while at the same time ensuring accuracy of naming and adherence to the naming code.
MYCADLAYERS is supported by a range of automated commands that ensure ease of use such that layer visibility can be automatically and rapidly filtered for any one of seven properties including drawing type, view-point and view-ID (level, section etc.). In this manner an entire set of drawings; plans, elevations, sections etc. can be created within a single model single file.
MYCADLAYERS’ layernames are made up of twelve characters in seven fields but are nevertheless shorter than national Standards. An important difference in MYCADLAYERS is that they include fields for color and line-type that in addition to providing additional layer separation allow automatic assignment of color and line-type upon layer creation. In spite of the apparent complexity of MYCADLAYERS it is never necessary to use graphical layer manager layer tables except for interrogating drawings from other sources.
What are MYCADZONES?
MYCADLAYERS not only permits layer separation by drawing type but also by level. Coincident Overlay Modeling is designed specifically to support the creation of multiple WORKZONES within a single model. WORKZONES can be defined not just by drawing-type but also by view-point and view-ID. A number of commands are provided for filtering layernames to reveal the desired drawing types and view identities. (levels. sections) Entire WORKZONES (consisting of many layers) can be copied from one level to another automatically changing the view-ID field to another ID or level in the process. WORKZONES can be automatically resolved separately or in any combination for editing or printing. This is especially beneficial for checking component alignments and clashes.
Automates Layer naming. Eliminates confusion, delay and error in layer naming .
Effective layer naming standard solves Layer NAME problem.
Custom Layer MANAGEMENT commands eliminate difficulty of filtering layers.
Supports OVERLAY modeling and WORKZONES.
Aids viewing and printing
Reduces drawing file size.
Provides a link to BIM.
Produces more intelligent and more accurate drawings
What if the MYCADLAYERS system does not suit my profession? Go to MYCADLAYERS Q & A
A Layers feature is the single most useful aspect of CAD and every "Layers" tutorial that you will find on the web will advise the use of a Layer naming Standard. But the advice generally stops there because no one seems to have settled on a really workable standard. Both the American and European standards try to be everything to everyone but succeed at being of little use to anyone in actual practice. Nevertheless I strongly advocate the use of a standard; just not the ones proposed.
Everyone seems to agree that Layers are essential to CAD and a Layer Naming Standard is essential to the effective use of Layers but there are several National Standards and many more Custom Standards and little or no agreement on which one to use. To understand why you need Layers go to CADNOTES a simple but convincing explanation of why you need layers. To get a good understanding of Layers go to ENGINEERING.COM then think about how a layer naming strategy can really help in drawing management.
So which Standard should I use? The answer seems to be that you should use the Standard required by your employer as any standard is better than none.
Here is my personal advice:
This is a personal view challenging the regular explanations of CAD layers. It includes references to MYCADKEYS and MYCADLAYERS that are proprietary (but free) products and thus should be considered in conjunction with other “authorized” explanations.
MYCADLAYERS, like many other Layer naming standards, extends the properties of objects by embodying properties in the Layer-NAME. These are: Object-type, Color, Line-type, Job-status, Drawing-type, View-point and View-ID. An example layername might be: "BRI 3 7 X 511 P 02" (expanded for readability) that means: "BRIck color3(green) line-type dashed(7), work-phase Xisting, drawing-type 001, Plan-view level 02". This first defines the building element's drawn graphics, its project status, and workzone (drawing identity). Looking a little closer it can be seen that the first section is five characters, the second is a single character and the last six.
If a drawing has a simple single purpose there is no need to include the last seven characters. A five character layer name may be sufficient and in fact for many simple drawings any more is a waste of time. So much for complex National Layer-naming Standards. MYCADKEYS provides an automated system for generating and managing Layers and permits the use of either five or twelve character Layer names depending on the complexity of the drawing or may simply be turned OFF if not needed.
MYCADLAYERS uses a built-in automated Lisp functions to create and manage layer names. A typical command is LR (Layer Resolve) that prompts the user to enter layer field codes for Drawing-type, View-Point and view-ID and will then freeze and thaw relevant layers to reveal the required WORKZONE of the drawing.
LR+ (Layer Resolve plus) and LR- (Layer Resolve minus) allow for various combinations of WORKZONES to be compared for alignments and completeness.
LR is designed for Model-space and a complimentary function WR (Workzone Resolve) manages the VPLAYER command in Paper-space to freeze and thaw the contents of Viewports. MYCADLAYERS performs the WR operation automatically, simply by scanning the layer name of each selected Viewport using the embodied Workzone information to automatically VPLAYER FREEZE and THAW layers as required.
AutoCAD's LAYERSTATE functions can only restore saved collections of layers and ignores any new layers created since a State was saved however MYCADLAYERS' Layer Resolve and Workspace Resolve functions freshly filter ALL layers new and old to produce a correct and up-to-date display thus avoiding the need for new layers to be added by the operator before re-saving the state.
MYCADLAYERS provides BOTH a dialog and a Command line interface both of which are much faster and simpler to use than much simpler to use than Autocad LAYMAN layer tables. Gone is the problem of remembering how to create new layernames. Command line functions automatically prompt the user through the process of naming. Alternatively, while learning, one can use the built-in layer dialogue.
Automatic Layer Dialogue creates layers to naming standard and applies correct color and line-type automatically.
A typical multi-level, multi-drawing type model with five overlaid plans - all layers visible.
The same drawing in Paperspace with Workzones (Layers) Resolved to display the five separate floor levels: