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Customer Profile Data
Q-CAD creates a "customer profile" to ensure consistency across multiple
projects. When a new project is received by Q-CAD, the standards, blocks, fonts, titleblocks, etc included in the customer profile are applied to each project. A customer may also have multiple "project
profiles" to handle concurrent projects. Before beginning a large conversion project, Q-CAD recommends that the customer send several documents, along with the specific layering standards, blocks, etc.
for an initial conversion. This way, Q-CAD can work with the client to assure that conversions meet specific standards before the actual conversion project begins.
Layering Standards
CAD layering standards are
essential to seamlessly share graphic information data throughout the CAD industry. Implementation of layers in a CAD file enables better management of visual information.
The most widely used layering
standards have been developed by the American Institute of Architects (AIA). Q-CAD automatically uses the AIA layering standards during the conversion of a document unless the client has supplied their
own set of layering standards.
CAD layers are organized into
major categories or groups. The major groups are further subdivided into minor groups. Each group represents a layer in the converted CAD file. Each layer is labeled using a consistent, easy-to-remember
abbreviation. The major groups defined by the AIA include:
A Architectural (Samle Architectural Layering: Page 1, Page 2)
C Civil
E Electrical (Sample Electrical Layering: Page 1)
F Fire protection
G General
H Hazardous materials
I Interiors
L Landscape
M Mechanical (Sample Mechanical Layering: Page 1)
P Plumbing
Q Equipment
R Resource
S Structural
T Telecommunications
X Other disciplines
Z Contractor/shop drawings
For more information about the AIA CAD Layer Guidelines, please contact:
Task Force on CAD Layer Guidelines
C/o The American Institute of Architects
1735 New York Avenue, NW
Washington, DC 20006
www.e-architect.com www.aia.org
CAD Symbols, Blocks, Attributes
Symbol libraries, blocks and
attributes are additional tools designed to better organize the CAD entities in your converted CAD files. Advantages of incorporating symbols, blocks and attributes into your CAD files is that they
enable you to automatically export CAD data into other report forms. For example, you can automatically count the total number of door symbols, window symbols, etc. that appears on a floorplan.
Alternatively, you can export floorplan attributes such as room name, room number, area, perimeter, etc. for use with space management software applications.
At Q-CAD, we encourage our
clients to submit any predefined symbols, blocks and attributes with each order. During our conversion process, we then automatically incorporate this reference data into each CAD file. Symbol libraries,
blocks and attributes are not necessary, however, they will provide added control and flexibility for your final converted documents.
Ambiguities and Data Conflicts
Ambiguities can exist on almost
any sheet and there must be conversion "rules of thumb" in place to handle them. These rules also ensure communication consistency between Q-CAD and our clients. Some of our common ambiguities and
"rules-of-thumb" include: undimensioned original drawings, unclear data on the original documents, and data conflicts.
Undimensioned Drawings
In cases of converting undimensioned drawings, or drawings with fewer
than 20% dimensions shown on the original documents, our CAD operators perform the following heads-up digitizing procedure:
1. The document is scanned to create electronic raster TIFF image.
2.
The raster image is imported into AutoCAD, Revit, Architecture (ADT), or Microstation and appears as a background image. During the drafting process, the CAD operator uses the background as a reference to create the CAD file. The CAD operator manually draws all entities such as text, notes, title blocks, drawing titles, detail references, schedules, etc. During the conversion, the CAD operator also incorporates layering, blocks, etc. provided by the client.
3. The CAD operator performs Level 1-QA to ensure the document matches the original.
4.
The file enters Level 2-QA where the CAD manager plots the file and compares it to the original blueprint document for accuracy. Errors and omissions are noted and the CAD manager works with the CAD operator responsible for the hand redraw to assure that all errors and omissions are corrected.
5.
The file enters Level 3-QA where the CAD manager again reviews the corrected document for quality assurance.
6.
The electronic file is transferred to Level 4-QA. The electronic file is visually compared to the hardcopy original document. Once Level 4-QA testing is completed, the files are ready to be distributed to the client.
Unclear Entities on Original Documents
When data on the original
documents is unclear or difficult to interpret, the CAD operator creates a "README" layer in the CAD file. For each unclear entity that appears in the converted CAD file, the CAD operator inserts a "red
box". The red box is an identifier that displays the unclear data. Our clients can then quickly zoom into the unclear area and make any necessary modifications. The "README" layer also goes through four
levels of QA and will remain after Level 4 QA only in cases where the data was too unclear on the original sheets to convert.
Data Conflicts
Since, Q-CAD operators manually
redraw each entity shown on the original document, occasionally a dimension shown on the original document will conflict with the measurement scaled by our operator. In such cases, the actual dimension
shown on the document is used as the default. The scaled CAD dimension is shown in RED on the "README" layer. Therefore, we can ensure that all of our conversions are dimensionally correct.
Establishing CAD Standards
CAD documents are used by many disciplines and for many purposes. Before beginning a CAD conversion project, many
companies establish a set of internal guidelines to make it easier to reuse drawings for multiple purposes. Such guidelines ensure seamless communication when CAD documents are created, used, or revised
by employees, consultants or contractors in multiple locations or by other software applications that work with CAD files. Conversion standards also automatically manage the searching and indexing of
large volumes of CAD files.
During our experience in the CAD
conversion business, we have observed many different conversion standards. Given this knowledge base, we have created the following list of 6 recommended standards that you may choose to consider when
developing your own standards.
Drawing Standards
Several primary conversion
standards should be adhered to during the translation of paper documents into CAD. These standards include the following:
Title block: Each
converted sheet should use the appropriate title block, logos, and sheet borders. A title block should be created for each sheet size: A, B, C, D, E
Model space:
All document entities, dimensions, symbols, notes, etc. should be placed in Model Space. Q-CAD recommends that all entities be drawn in Model Space.
Variables:
A set of present variables can be established for the document conversions to ensure consistency.
File Name – Drawing Number
To easily identify a specific
building or drawing, the converted CAD files should be saved using a combination of the building name/number and the sheet number. As each document is converted, it should be added to an electronic index
so that it can be quickly cross-referenced and located. The following example illustrates an easy to locate filename convention:
Format: EJH00101.DWG
Where: E=Drawing Type (such as E=Electrical)
JH=Building number/name (such as Johnson Hall)
0101=Drawing sequence number (sheet number)
01=Revision number or letter
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Drawing Types
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Letter
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Drawing Types
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Letter
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Architectural Base
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B
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Civil, Structural
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C
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Electrical
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E
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Furniture, Interiors
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F
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Flow Diagram
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N
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Mechanical Utilities
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H
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Layouts
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L
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Machinery
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M
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Piping
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P
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Reflected Ceiling
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R
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Fire Protection
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S
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Layering Control
The most widely used set of layering standards was developed by the American Institute of
Architects (AIA). Q-CAD automatically uses the AIA layering standards during the conversion of a document unless a different set of standards has been provided by our client. Each layer is
labeled using a consistent, easy-to-remember abbreviation. The AIA Long Format consists of a single letter Major Group, a four letter Minor Group and a four letter Modifier. The major
groups defined by the AIA include:
A Architectural
C Civil
E Electrical
F Fire protection
G General
H Hazardous materials
I Interiors
L Landscape
M Mechanical
P Plumbing
Q Equipment
R Resource
S Structural
T Telecommunications
X Other disciplines
Z Contractor/shop drawings
The colors for each layer should be consistent and all objects shall be drawn in color BYLAYER.
This means that all objects assigned to a specific layer should be the same color. Occasionally, the need to create a new layer can arise in cases when custom defined, or AIA layering
standards are not available. Typically, any unused drawing layers should be purged from the converted CAD document.
Text, Dimensions, Linetype Styles
Standard text fonts are ROMANS and ROMAND. Typically, a standard text height should be
defined, however, the text width should be flexible to accommodate the contents of each sheet. Often, in the case of a crowded sheet it may become necessary to adjust the text width
to properly fit the text on the sheet. The following illustrates a text style:
Example: 08ROMANS15
Where: 08=width factor=0.8=width of letter
ROMANS=font
15=oblique angle (omitted when set to 0)
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Text Styles
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Font File
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Width
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08ROMANS
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ROMANS
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0.8
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0ROMANS
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ROMANS
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1.0
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06ROMANS
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ROMANS
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0.1
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Blocks
Blocks are common for repetitive entities that exist on a document, such as doors, windows,
toilets, etc. To ensure that all employees, contractors, and consultants use a consistent set of defined blocks, we recommend that a block legend be created. This legend should define all
blocks. Blocks should be consistent among all drawings included in a set of plans or a project. For example, if a call-out block "X" is used in one drawing, it must appear as the same block
"X" in all other drawings. Blocks should be created on Layer 0 and then inserted onto their correct layer in the drawing. When the block is inserted, it should be re-scaled to match the
scale of the current drawing. All blocks should be listed in the drawing index, while unreferenced blocks should be purged from the drawing.
Polygon Layer
CAD documents are often used by other software applications that work with CAD files.
Architects and planners often need facility data such as the area square footage of a room or a section of a building. Whereas, a structural engineer may need to find the cross-sectional area
of a beam. The solution: add a polygon layer to the document. The CAD operator simply draws a closed polygon over the top of each room and over the entire building. The polygon layer
then enables the export of precise information about the drawing such as room area, perimeter, location of an object, etc. that can be used with other software applications.
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