20 Jun Sketch-Measure-Scan
Hello, Welcome back to my blog!
The past four weeks have been very fun and exciting over here in Washington DC. I’ve been learning so much about how to do proper documentation and using programs to process different kinds of data. The truth is nobody can ruin the hype or the fun that I’m having while I’m doing my work. This week I’ll talk to you about what the documentation process involves and how its conducted, as well as all the software that I’m learning to use and how my experience has been so far.
Like I mentioned in my previous publication, our site is located in Washington, DC in the Woodley Park neighborhood. The original owner, C. H. Smalls took out a building permit for ten row houses in 1922. Later, they were designed by architect George T. Santmyers, who was the most prolific designer of row houses in Washington.(footnote 1.) By September the construction was mostly done. So our house is almost 100 years old. Wow!
The House is a pretty small structure measuring approximately 20ft by 54ft including the front porch but excluding the garage and back patio. Its two stories and it includes an attic and basement. It has very interesting features since it was designed to take advantage of natural light as much as possible. Some skylights were included on the designs that you will see in a section at the end of the summer. So I can say that it’s a fairly small house that is very comfortable but a little bit challenging to document.
How does the documentation process take place? You might ask.
First, we visit our site and review the spaces and which drawings are necessary. For this project we will be drawing 2 floor plans a section (think that you are slicing a piece of cake, same thing but a building) and elevation. Each team member has a task, we each get to hand sketch a part of the floor plan. We do these sketches in grid paper with pencil and the goal is to do it as proportionally as possible. After the sketching is done we work together to hand measure with a tape-measure each part of the house. We use a methodology for this specifically for HABS drawings. We use this method so everything is uniform and if someone in 50 years looks them up they can understand what they are reading. You can find the guidelines if you click here: https://www.nps.gov/hdp/standards/habsguidelines.htm
On another visit, we arrived with a laser scanner and camera. The laser scanner literally scans its surroundings creating a digital three dimensional point cloud (Yes imagine a cloud composed of many, many points) that is the shape of what was scanned. I’m not gonna lie, this was super useful to learn how to use since it helped us produce the base geometry of the elevation drawing since we couldn’t reach the highest parts to measure them. This scanning process involves so many things, but you would take several scans of the same place but in different locations to grab as much data as possible, then in another program they are all stitched together to form one point cloud. At the same location of the scanner we also took images to create panorama photos that are later also going to be stitched to the point-cloud.
After we have all the measurement and scanning data the computer work begins. We start by using AutoCad to draw digitally the plans with the measurement we used; and HABS has guidelines for that too. Now the juicy part starts… processing the scanning data. For this part, our trusty instructor Jason taught us how to use PTGui, Cyclone and Cloudworks. It’s my first experience using any of these programs, and although at first it was daunting and challenging it was very rewarding to see the results and gain this experience (something new for the resume! Thanks Jason!). With PTGui we eliminate information that we don’t want from the Panorama images, and this is where the panorama is stitched together. Also, from PTGui we cut up the panoramas into six square images that are later stitched to the point-cloud. The purpose of the images to the point cloud is to give it real color and texture to the scan, an example can be seen in the image above. Cyclone is the program that stitches the Laser scan and images together. After all of that is processed, it’s uploaded and through a plug-in in Cad (Cloudworks) we open the cloud and can do slices through the cloud and draw over it.
The laser scanning can have other uses apart from a reference to do drawings, but virtual tours can be created. For examples about this you can click here:https://www.nps.gov/hdp/exhibits/amb/amb_index.htm
The past few weeks have been filled with work, but very rich in experience. It has all been fun so far and I have high hopes it will continue so. It makes it even better to have supervisors and instructors that make the job fun and entertaining (That is for Robert and Jason that are always making us laugh).
See you in two weeks,
More Link to explore:
HABS Guidelines https://www.nps.gov/hdp/standards/habsguidelines.htm
Heritage Documentation Program https://www.nps.gov/hdp/index.htm
Want to see more of what HDP and HABS does? Look it up in Facebook https://www.facebook.com/HeritageDocumentationPrograms/
- Information provided by project historian Kim Hoagland.