Using photogrammetry and 3D-printing to bring real life buildings to the wargaming table

Have you ever looked at a building or terrain feature and thought: "That would make a cool piece on a wargaming table"? Well, it's quite doable using the marvels of modern technology.

Ok, so I bought a drone. I already have a 3D printer. I wondered if there's some synergy there and having seen some articles on photogrammetry, using the power of computer science to build 3D models out of a series of photographs that is, I decided to give it a go myself. Turns out it's much easier to do than you'd think thanks to some excellent products out there, and it's not expensive, either!

First off, you'll need some photos to work with. Photogrammetry algorithms work by detecting keypoints and features in a photo, and linking those to the same points in other photos, taken from different angles. The result will be more accurate the more photos you have and the better your image quality is, obviously.

The drone I have is a Mavic Mini, a small drone that costs about 400 Euros. It has these handy flight macros where the drone takes a video while flying a certain flight pattern. I grabbed a video where the drone did a loop around my subject: an old, collapsing barn in the middle of a field. Just one loop is enough, although later on I realized it would have been handy to get some additional imagery way up close too.

The software I used to build the 3D-model is called RealityCapture. The software is free, but you have to pay for the models you export from it. That means you can freely tinker around with the software and see if you get good results before committing your hard earned coin. The model I created ended up costing a couple of Euros, which is reasonable considering how advanced the stuff happening under the hood is.

RealityCapture uses images instead of a video, so I had to export those from my drone video. With VLC Player, I could do that pretty easily, and I took 10 frames for each second of video. I don't know if that was overkill or not. The price of the exported model depends on the number of frames you use for the model, so you might save on the cost by reducing the frame count.
The photogrammetry process was amazing easy. I just told RealityCapture which directory the images were located in and pressed a button. Boom. I had a model of the barn. Now, I just needed to do a bit of tinkering on the quality settings, doing a noise reduction filter and export the model. That model can then be used as an asset in a 3D project, you can look at it in virtual reality (I have VR goggles too, I'm into gadgets, all right?) and yes, run it through your 3D printer.

To print the model, I first cleaned it up a bit with Blender and Meshmixer. This probably took the most time in the project as I have zero experience in 3D modeling or sculpting and had to learn everything from scratch. There are some unwanted extrusions and a mass on the inside of the model where the camera couldn't reach. Also, the surface texture is pretty subtle, so I tried my hand at enhancing it in some places. I'll discuss the surface textures in a bit after I show you the end result.

I sait it is collapsing. That's why the walls are all wonky!

I used Anycubic Photon to print the barn in 6mm scale. I think the level of detail in this model would probably be enough for 15mm, but larger scales would probably be a stretch until I make models with better surface texture. A quick paintjob later and you can see the results:

I'm really happy with how it turned out and after you know your way around 3D sculpting software, I think you can do a building in an hour. once you grab the footage. As you can see from the greyscale 3D model, the surface texture is thwere, but it's in "true scale" as opposed to the exaggerated detail you see in wargaming. This means buildings built this way rely on you to bring out the surface texture with your brush and paint some on, instead of just letting the wash settle in the recesses.  Still, they'll blend in with my regular stuff easy enough.

The barn next to a Total Battle miniatures cabin and a 3D printed tank. I think I made the model a touch too small, but big buildings tend to get in the way anyway :P

So where to next? This method will be nice to get models of some of the famous surviving buildings of period battles. Also, this method can be used to capture other landmarks too. Say.. you wanted an accurate model of the Devil's Den at Gettysburg, which is something very recognizable and maybe difficult to reproduce using traditional means? Just have someone buzz around with their drone there (when permitted to do so) for a while and you can upload the model to the 'net for all to use. Speaking of which, I tried uploading this to sketchfab, but the project size was too big for their free account, so I'll need to work on the level of detail or something. Stuff to learn! If you have any tips on how to make stuff like cleaning the models or enhancing the surface texture, let me know!