Paper to CAD Conversion for Preservation of Old Buildings
Historic preservation has evolved into a broad-based popular movement with wide support. Historic preservation can take many forms, from the preservation of historic districts, sites, buildings, structures, and objects to the preservation of important documents, papers, drawings, and blueprints. Whatever is being preserved, the reasons were given for the preservation usually include the desire for a tangible sense of permanence and community, the embrace of history and heritage, and, often — economic success. Recognition that historic preservation often is associated with economic success is important when the overall costs of preservation are considered.
Historic Preservation Often Starts with Paper Documents
When discussing old buildings and structures, any documents associated with them are usually quite old. In the course of time, the quality of old drawings, blueprints, and documentation disintegrates; the paper gets brittle and it powders as it is handled. Eventually, this old building documentation will disintegrate if it is not preserved. Preserving this old documentation is important, not only from the historical perspective of the documents themselves but also because this documentation can contribute to the knowledge of the underlying structure of the building for renovation and preservation.
There are environmental factors one must consider in preserving old building blueprints, drawings, and documentation. Protecting paper documentation requires considerable attention to humidity and temperature, as well as light and pollution exposure. Often the blueprints for old buildings, if they even exist, have been stored in an out-of-the-way attic storage space or a damp basement, and they begin to crumble as soon as they are handled. Handling such documents with bare hands will only help in the destruction of the document, which is why you should always use soft gloves to work with these types of documents.
Most often, the best way to preserve the original building documents and help to ensure the building’s historical integrity is by scanning the blueprints that exist, converting to a CAD program and supplementing with 3D laser scanning of the actual building.
Converting Blueprints to CAD
Blueprints can be scanned using a large format scanner and then the scanned drawing can be converted via a process called raster to vector conversion into a CAD drawing (for instance, AutoCAD). In the case of historical blueprints, which are in delicate condition, the blueprints should be handled with special cloth gloves and inserted into a protective plastic sleeve for the scanning process. Once the basic blueprints are scanned and converted, additional information can be added manually to the CAD drawing, using old photographs, renderings and 3D laser scanning of the actual building.
Ultimately, in the hands of experts at CAD restoration, 2D plans and even 3D building representations can be created which can aid in the preservation and restoration of the building.
Using Restored CAD Drawings to Aid Historical Preservation
According to the United States General Services Administration Historic Preservation Library, “Historic preservation services embrace a range of activities that include preservation, rehabilitation, restoration, and reconstruction. Although portions of each service overlap with others, the following are the accepted definitions:
Preservation applies the measures necessary to sustain the existing form, integrity, and materials of a historic property. Preservation work generally focuses on the ongoing maintenance and repair of historic features and materials rather than extensive replacement and new construction.
Rehabilitation adapts a property for a compatible use through repair, alteration, and addition while preserving those portions or features that convey its historical, cultural, or architectural values.
Restoration accurately depicts the form, materials, features, and character of a property as it appeared at a particular period of time. Restoration retains as much of the fabric from the historic period as possible. Inconsistent features may be removed and missing features faithfully reconstructed in accordance with the restoration period.
Reconstruction depicts, with new construction, the form, materials, features, and character of a property that no longer exists, as it appeared at a particular period of time, usually in its historic location.”
All of these activities begin with an accurate CAD drawing of the building. So, from paper — to CAD — to historic preservation helps promote the cultural and economic value of historical buildings.