AR Digitech Drafting Procedure
AR Digitech follows the steps listed below to convert drawings into
CAD file formats. The document conversion is accurately performed
using AutoCAD & ArchiCad software applications. Below is a brief list
of steps performed by us.
Your original paper documents reviewed by our staff engineers
and architects. Your special requirements often include: layering
guidelines or standards; titleblocks; blocks, fonts; hatching; file
naming conventions. A technical staff representative will contact
you immediately if your project requirements are not completely
understood. A CAD operator is then selected based on the project
type and complexity. The operator is supplied with written detailed
instructions fully describing your project.
The CAD operator manually scales the actual dimensions, bearings,
distances and coordinates from the original document and then draws
each entity into CAD. During the conversion, each entity is placed
on the appropriate AIA or custom layer, and any blocks supplied by
the client are incorporated into drawing. The result is a
dimensionally accurate, layered file.
The CAD operator performs Level 1-QA to assure that the converted
file matches the original document.
The file enters Level 2-QA where the CAD manager plots the file version and compares it to the original blueprint document for
accuracy. Errors and omissions are noted and the CAD manager works
with the CAD operator to assure that all errors and omissions are
corrected as necessary.
The file enters Level 3-QA where the CAD manager reviews the
corrected document for 100% accuracy.
The electronic file enters Level 4-QA where it 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.
Customer Profile Data
AR Digitech creates a "customer profile" to ensure consistency
across multiple projects. When a new project is received by us, 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, We recommend that the customer
send 10 – 20 documents, along with specific layering standards,
blocks, etc. for an initial conversion. This way, we 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 set of layering standards has been developed by
the American Institute of Architects (AIA). We automatically use 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
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
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 floor plan. Alternatively, you can export floor plan
attributes such as room name, room number, area, perimeter, etc. for
use with space management software applications.
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, 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 AR Digitech 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
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 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. 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.
4. The file enters Level 3-QA where the CAD manager again reviews
the corrected document for quality assurance.
5. 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, our 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. 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. We recommend that all entities be
drawn in Model Space.
Variables: A set of present variables can be established for the
document conversions to ensure consistency.
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.
