Tag Archives: evaluation

Technical Elevation Drawings – exterior and interior

Exterior Elevations

Exterior Elevations

Here I am posting a few drawings from a project completed about 18 months ago.  These drawings depict the existing conditions of the Luzerne County Courthouse which is located in Wilkes-Barre, PA. More on the building can be found here.  I prepared these for a team of architects and engineers who were to conduct a survey of these surfaces in preparation for an extensive masonry and stone rehabilitation project.  It is a beautiful building with a grand atrium reaching up through the building.  I also did drawings of this interior space.

Interior Elevations

Interior Elevations

I am posting these to show that, for all the value of rectified imagery, point clouds, three dimensional models – sometimes the most apt documentation is the relatively “old school” approach of using 2-D drawings to depict 3-D conditions through plan elevation and section.  In the end, the documents that I have prepared for clients over the years have had to pass this test: Will these drawings help my team to communicate easily together when assessing and discussing the problems and solutions at hand with a given building?  Will these drawings help me to accuractly assess the scope of work involve – and, will I beable to use them to communicate with and direct the contractors in the field who are doing the actual work to the building?

Earlier this week I was giving a presentation to students at the University of Virginia.  I started off showing them work that I did 15 years ago when everything was more or less analog in nature, later showing how fantastic it is now to be able to merge raster and vector data together digitally. And then I thought of these drawings and how deftly drawings can handle such complex forms with precision and efficiency.  As an industry, we are doubtless moving towards wider use of three dimensional modeling and Building Information Modeling (BIM) – yet I admit to having a fondness for the “old school” approach that I cut my teeth on, so to speak.

View of building exterior

View of building exterior

View through atrium to dome

View through atrium to dome

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Franklin & Marshall Exterior Survey

Old Main at Franklin and Marshall

Old Main at Franklin and Marshall

Last spring I did some work at Franklin and Marshall College in Lancaster, PA.  I prepared a combination of measured drawings in CAD linked  to rectified photographs of the three oldest structures on the campus. These were then used as base documentation for an assessment of the existing conditions of the masonry surfaces across the extent of these buildings’ exterior facades.

The sequence of this work went roughly as follows:  I first shot photos of all of the buildings from points of view available on the ground (using a specially calibrated digital SLR).  Back in my offices in Virginia I used photogrammetric software to “back calculate” the camera stations and to make precise 3-D measurements of points on the three structures.  I used this dimensionally accurate point cloud as a reference to create rectified photographs of the surfaces visible from grade.

F and M Old Main Rear Elevation

F and M Old Main Rear Elevation

Using the point cloud and the rectified photographs I then created measured line drawings of the structures and laid them out onto tabloid size sheets for use in the field.  These were taken by hand up into an aerial lift so that conditions could be noted with a fair degree of accuracy once assessment were made both visually and manually.

tabloid size field sheet with notes

tabloid size field sheet with notes

Once the assessment was completed the data recorded on the field sheets was entered in the CAD drawings.  At this point the line drawings in CAD were enriched by a mosaic of rectified photographs visible inside of AutoCAD.  This allows for an accurate transfer of notes from the field to eventual construction documents.  A sketch of an area or region can be transferred to CAD and become dimensionally reliable.  This is a very important step because it provides for an accurate tally of areas to be treated in one way or another.

aerial lift

aerial lift

Since the main structure was rather tall, I also returned to the site to go up in the aerial lift to collect more photographs to further enrich my drawings with better rectified images of areas that were either blocked by vegetation, neighboring buildings, or were too foreshortened to provide good rectified images.

F and M Old Main Rear Elevation with photos

F and M Old Main Rear Elevation with photos