3D printing a structure

I’ve met several people modeling the 1920s. Dr. Dave Campbell has focused on part of the Toledo & Ohio Central in western Ohio. He shared this update on a recent structure project.

My real-world modeling skills have always been somewhat limited and have not improved in my advancing years. At the same time, my virtual modeling has become a strength.

Creating 3D models does not require the same level of vision or eye/hand coordination. When it became time for me to create one of the signature structures on my layout, it wasn’t surprising that my first instinct was to fire up my laptop and start drawing with my 3D modeling software.

Allen County Historical Society. (Lima, Ohio) collection

The structure I need is the yard office at Corning, Ohio, the southern terminus of my layout.

Allen County Historical Society. (Lima, Ohio) collection

The prototype has a few complications. Not only is there an attached tower for the crossing guard, but we have a double hip roof with the roof line offset by four feet.

In addition to these photos, I’m fortunate to have dimensional drawings of the structure, thanks to my friend Dave Chapman. He wrote an informative article published in the Fourth Quarter, 1988, edition of the Central Headlight. With this resource in hand, the full-size 3D drawing of the of the yard office came together quickly.

I use ViaCAD software for my 3D drawing. I drew the model as full size. The software can reduce the model drawing scale easily. The scale factor for HO is 1/87.1, or .01148105, which is the maximum precision in ViaCAD. If I wanted an O scale model, for example, I would have used a scale factor of 1/48.

The wall sections (minus the windows, doors, and trim) were printed as one group of parts. The window, doors, and trim were a separate group. I painted the parts with my airbrush and kept the fussy brush painting to a minimum. Recall my limited modeling skills from earlier. I painted walls and doors in a light green, and the windows and trim in a contrasting dark green.

I primed the parts with Tamiya fine gray primer.

After the primer was dry, I airbrushed the wall sections with the light green and the window/trim sections with the dark green trim color.

I decided to create a base for the structure that would fit inside the walls. My 3D drafting software makes it easy to draw a 2D outline around parts, like the inside of the walls. I printed this on card stock, cut it out, and used it as a cutting guide. I produced a correctly sized base from 0.08-inch thick styrene and cemented lengths of 0.1-inch square styrene stock onto the base to serve as glue surfaces for the walls.

The walls fit together as designed. I had included bevels in the ends of the walls to ease assembly. Since the rear of the building will not be visible on my layout, I made those sections from plain styrene.

Now I needed to focus on the roof. As I was designing the roof structure, I decided to use 3D printed interlocking roof supports. I drew the supports with the slots for easy assembly.

I again created 2D cutting guides for the eight roof panels and cut them from 0.01-inch thick styrene sheet. The prototype yard office had a slate roof. I used strips of Tichy slate shingles cemented to the styrene roof panels.

Here’s the assembled roof with flashing cut from aluminum foil tape.

And finally, the roof after painting.

I followed the same steps for the watchman’s tower portion of the structure. After test fitting the parts, I was surprised there was very little fiddling and adjusting. The tower assembly was added to the base structure.

The access staircase and the tower door platform were 3D printed, vastly simplifying construction. I added upright supports and handrails made from scale 2×2 styrene and airbrushed the assembly before adding it to the structure. Adding the roof sections competed construction.

Lessons learned

As noted, I lack the modeling skills to scratch build this complex structure, at least within a reasonable time frame. The use of 3D printed parts enabled me to add this signature structure to my layout relatively quickly and well within my skills.

Predictably, the hand painting portion of the project was the most problematic for me and took by far the most time. After numerous touch-ups, examine a closeup photo, and repeat cycles I finally gave up. I examined the model from three feet, and said, ”Good enough!” As I design the next project, I’ll look for ways eliminate hand painting altogether! All the airbrushing can be done with the parts on the sprues, much like a laser-cut kit.

Several local modelers have invested in the latest generation 3D printers that are priced for the hobbyist ($300 to $500). The quality of prints they are able to easily produce rivals the quality of the printed parts I ordered from Shapeways for this project, at one-twentieth the cost. This makes it possible for me to add all the additional structures I need at minimal cost.

Finally, because of the advances in the printing technology, it is possible to print an entire structure (less the roof), instead of printing individual parts and assemblies. Possible downsides to this approach include a loss of quality compared to parts printed in a flat orientation; and even more time spent using masking tape.

I thank Dr. Dave Campbell for sharing his impressive work. Learning new digital drawing skills can be used for many projects. Printing components for a unique structure is just one possibility. Dr Dave has 3D designed several freight cars from the Teens and Twenties, and created decal art for several freight car projects. Investing time to learn and hone your computer drawing skill can open many possibilities.

Thank you for visiting the DesignBuildOp blog. To post a comment, follow the instructions in the section below. All comments are moderated. Please share the blog link with other model railroaders.

To subscribe to this blog, add your email address to the function at the bottom of the right column on the main page.

6 thoughts on “3D printing a structure”

  1. Eric

    Holy smokes! I just sent the NYCSHS an article about the T&OC from my perspective of working portions of the line in the 1970-80s. I worked as a block operator at Corning off the extra board. The yard office building Dr. Dave is building was long gone. Note the landing on the side of the building in the background. Corning and othe towns such as Shawnee had dozens of buildings with second story overhanging porches. Also just sent a set of photos of NYCS cars that I did in HO scale to NYC Modeler E-Zine.
    Did not know Dr. Dave was doing the T&OC. Looking forward to seeing more. I model in O scale and recently have explored doing DT&I from 1920s to end of steam.

    1. Thanks for the comments, Jim. I’m looking forward to your articles!
      DT&I, eh? I have many memories of standing near the tracks in Quincy, Ohio as a kid, watching Big 4 H5s cross the diamond. Sadly, I don’t recall ever seeing traffic on the DT&I.


  2. What kind of printer did you use? FDM or resin? Great application of these new technologies to our hobby (and a great finished product btw!).

    1. Thanks for the kind words, Tim. The parts for the current project were done at Shapeways using Fine Detail Plastic. It’s an acrylic material and the production process results in very smooth surfaces, particularly if printed in a flat orientation.
      Next project will be the Corning passenger depot next door and I plan to ask my local friends to do the printing. They’ve done some freight car parts for me so I know the quality is equivalent to Shapeways. I just don’t know which printer they have off the top of my head.


    1. Thanks, TJ. And if I’d tried to scratch build this structure and showed you the result, the last thing that would occur to you would be, “great looking building.”

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.