Hybrid Raster/Vector CAD Market Analysis

Overview

Present methods for handling, storing, and maintaining paper drawings are cumbersome, time-consuming, and costly. The advent of Hybrid Raster/CAD technology has helped to dramatically reduce these costs. User acceptance and ongoing vendor evolutions have fueled continued improvements.

The cost benefits of hybrid editing begin with scanning manual archives into raster format and bridging those files into a Native CAD system. These systems can include AutoCAD, CADAM, Intergraph, Autotrol, and CV. All early adoptions were based on the proprietary CAD vendors' format, which is then merged with sometimes proprietary and sometimes open raster standards. The raster data was typically imbedded within the native CAD files, with the exception of the Autodesk environment.

Intergraph was the strongest proponent of hybrid technology through buyouts of ANAtech and Optronics. Other CAD vendors who offer hybrid solutions include Autotrol, Computervision/Formtek, and most recently, IBM CADAM and MicroCADAM (both through OEM alliances with GTX).

While Intergraph's mapping/GIS user community quickly adopted hybrid editing methods, the AutoCAD market was much slower to develop. The more widespread AutoCAD community has had to rely on third party vendors. This has resulted in a more painful and slower development process for hybrid technology.

Image Systems technology and its' CAD Overlay ESP product was the forerunner in bringing hybrid technology to the mainstream AutoCAD market. Image Systems designed ESP to use AutoCAD as a background user interface and vector drafting tool. However, incomplete rasterization and a lack of other basic raster drafting functions forced users into a hybrid situation.

The Autodesk Market

Raster vendors including Image Systems, GTX, and Hitachi developed their own methods for handling hybrid data for AutoCAD applications. With the recent release of R14, Autodesk has joined the ranks of other vendors by introducing a standard format for handling hybrid files.

Considering that over 80% of all CAD files in existence are AutoCAD "DWG" files, this release will eventually help develop the acceptance of raster and hybrid drawings worldwide.

Autodesk's entry with R14 introduces the Image Support Module (ISM) which is included with the base R14 AutoCAD and AutoCAD Lite products. Autodesk and leading raster suppliers including Softdesk, Hitachi, GTX, Vidar, Contex and OCE jointly developed ISM. The intent is to have a universal standard within Autodesk "DWG" files which will provide raster images as block-like entities.

Hybrid Overview

History dictated that users want their files in vector format which guaranteed large conversion costs. Hybrid editing technology presented a new option for maintaining both raster and vector data within these scanned files more economically. This provided the opportunity for cost reduction and better data and revision management.

A hybrid file consists of scanned raster data and overlaid vector data. Typically, newer edits and additions or more valuable data like title blocks and extractable data is maintained in vector while background data is raster.

The primary benefit is in reduced costs over redraw or vector conversion methods. Why convert all components of a drawing when you are only making modifications to 5%.

The resulting hybrid database has correlation information required to bridge the raster image and vector coordinate systems together. This typically includes insertion datum point, scaling, and rotation.

The Hidden Costs of Hybrid

Paper based archives still dominate engineering departments and stimulate a hard look at hybrid editing options. However, problems have been identified with maintaining hybrid engineering archives. The following outlines some of the issues we have run into:

• Drawings scanned by various sources (external vs. internal) do not always contain consistent raster formats. Standards need to be in place for resolution, file encoding, and service verification.
• Lack of revision management tools can result in redundant or overlapping modifications requiring staff to redo changes.
• Improper use of Softdesk CAD Overlay has lead to hybrid files not purged or flushed. This process burns edits (rubs) into the original raster image.
• RLC stored raster files are proprietary in nature and require 5-10 times the storage demands of 2 dimensionally compressed TIFF or CALS files. Many early adopters of hybrid still use RLC files containing imbedded hybrid correlation (resource) information.
• The process of managing active drawings is usually a cumbersome manual process. Document Management capabilities may need to be put in place.
• Early adopters of CAD Overlay do not have the ability to perform selective raster to vector conversion.
• Viewers found in the market are not fully compatible with many available hybrid formats.
• Document management systems do not cleanly manage compound documents. When they do, the check in and check out procedures don't take hybrid into effect.

Cost Justification

When evaluating cost/benefit analyses of various methods for drawing revision, the hybrid raster/CAD approach is the clear winner. Elimination of the redraw, clean up, and verification processes found with vectorization contribute to the immediate cost benefits that are realized with this method. It also incurs the least labor requirements for the first revision and is the best approach when vector CAD is not necessary. Vector CAD represents the best subsequent revision cost savings when factoring longer-term life cycle costs.

Occasionally drawings will need to be converted to the native AutoCAD format. This is more typical for drawings with longer life cycles or when requirements dictate full vector format. One method of accomplishing this is for operators to manually redraw the drawings using overlay or heads-up digitizing methods at significant time and cost.

Cost justification and cost reduction benefits for the technologies described in this paper can be based on labor savings in the revision process alone. But there are also many other benefits:

• Increased value of the AutoCAD system by eliminating its use for tedious redraw by using raster to vector conversion
• A common and secure database.
• Reduced retrieval and print times.
• Redundant revision and CAD redo work can be decreased or eliminated.
• Reduced CAD and Hybrid revision times.
• Improved flow of information with Workflow and E-mail tools.
• Accurate correlation of the database with actual drawings.
• A potential immediate performance improvement of 47% can be realized by moving to the AutoCAD R14 environment from Dos or other releases.
• The R14 hybrid standard is new. Other third party products will probably need time to adapt to the new format standard. This could be an issue if data is being exchanged outside the company.

Moving Forward: Hybrid Drafting

Our recommendations for moving forward in the area of hybrid drafting are as follows:

• The hybrid data files should be standardized on a single raster format (TIF/G4 or CALS/G4). Existing files will require a translation process to the standard format. In addition, procedures need to be established for bringing externally produced files into the standard, thereby eliminating the varying formats that probably exist.
• Standardize on your CAD vendors standard, such as the AutoCAD R14 hybrid format, and migrate all hybrid files to this format.
• Incorporate an integrated hybrid redlining process with your document management software to eliminate lost work due to redundant revision cycles.
• Eliminate any CAD Overlay RLC files and move to a 2-D compression format (TIFF or CALS) to significantly reduce storage needs.
• Understand the benefits of hybrid as an alternative to full conversion.
• Use full vector conversion where and when it makes sense.

Moving Forward: Hybrid Document Management

A transition plan to migrate or integrate existing hybrid data into EDM/PDM is critical.

• Full Text searches should be implemented to take advantage of the benefits of hybrid title block data in vector form. This improves the search and retrieval process of the CAD operators beyond traditional field based indexing methods. By incorporating hybrid files with drawing title blocks in vector form, full text searches can be accomplished easily and quickly.
• Make sure your target EDM/PDM supplier has an understanding of hybrid data and has viewer's compatible. Otherwise, consider a duplicate database strategy whereby merged plot files (raster) are vaulted for distribution purposes.

Hybrid Vault Conversion and Accountability

Open Archive Systems is prepared to help in the process of migrating existing data into an updated hybrid revision and document management system. Specific needs and accountability will be identified after a preliminary needs assessment is conducted. Some common action items include the following:

• Help in the strategic planning and implementation phase of pre-EDM/PDM or post-EDM/PDM implementations.
• Help with the hybrid data indexing relationships while building an EDM/PDM vault.
• Evaluate the compliance of the target viewing tools with the hybrid formats being standardized.
• Position the revision process for long term benefits like selective conversion, full text index and retrieval and more.
• Provide custom utilities to migrate legacy hybrid data into updated standards.

This page, and all contents, are Copyright© 1999 by Open Archive Systems, Inc., Windham, NH.