Category Archives: Photogrammetry

3D Printers, Photogrammetry

3D Printing from Photogrammetry

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Blender

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What Have I Gotten Myself Into Now?

This was going be be a blog about using Blender to create 3D scenes. Sort of. I’m just barely starting to learn Blender, so it wasn’t going to be anything fancy or in-depth.

But, I went down a rabbit hole. Imagine that! I started with the ASDM Rock I photographed a few months ago (see my post PHOTOGRAMMETRY: 3D Models from Photos), and was going to try to add some sunshine, and animate the sun moving across the rock, and maybe in the future create some somewhat realistic looking grass around the rock. But, I got sidetracked and decided to try to 3D Print the rock. Not at full scale(!). Just a little plastic rock I could put on my desk.

Blender

OK, so what is Blender? From Wikipedia, “Blender is a free and open-source 3D computer graphics software toolset used for creating animated films, visual effects, art, 3D printed models, motion graphics, interactive 3D applications, virtual reality, and computer games.” Did you read all of that? Free. Open Source. 3D computer graphics software. Animation.

Blender is used to create everything from 2D and 3D still pictures to full length animated movies. Wow!

I’ve known about Blender for several years (at least). I’ve looked at it a few times, but every time the learning curve scared me off. But it can do so much. And FREE, so no big investment (except my time) to play with it. After playing a bit with Open Drone Map, creating 3D models from “just a bunch of photos,” I thought maybe I should look at Blender again. So for the last 4-6 months I’ve been watching tutorials on YouTube and LinkedIn Learning, being awed by what others have done with Blender, and wondering if I could accomplish anything significant with it.

Very brief recap of my blog on Photogrammetry: I shot 40 photos with my cell phone of this cool looking rock that is located in front of the Arizona-Sonora Desert Museum outside of Tucson, AZ. I then used Open Drone Map to process these 40 photos to create a model of the rock, and used Blender to do some very minor editing to eliminate the extraneous parts of the model. I uploaded the model to Sketchfab, where you can view it in all of its 3D-ness.

Starting with this same model, I used Blender to create a base and export it to an STL file, which can be used to print a 3D model. That sounds rather mundane, but I spent many hours trying to get the initial model ready for 3D printing. Several YouTube videos later, I managed to create something that would print nicely. I also added a little sunshine to the scene, just because I could.

For comparison with the printed model, here is one of the photos in the sequence that was used to create the model.

Rock at Arizona-Sonora Desert Museum Entrance
Rock at Arizona-Sonora Desert Museum Entrance

Here is the ASDM Rock, as rendered in Blender. I added a little sunshine to the scene, just because I could :-).

ASDM Rock, from Open Drone Map model, rendered in Blender
ASDM Rock, from Open Drone Map model, rendered in Blender

The final result? Here is my printed “rock.” I think it rather accurately represents the original rock!

3D Print of Rock in Photo Above
3D Print of Rock in Photo Above

Photogrammetry, Photography

PHOTOGRAMMETRY: 3D Models from Photos

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(From Autodesk’s website:) What is photogrammetry?

Photogrammetry is the art and science of extracting 3D information from photographs. The process involves taking overlapping photographs of an object, structure, or space, and converting them into 2D or 3D digital models.

Photogrammetry is often used by surveyors, architects, engineers, and contractors to create topographic maps, meshes, point clouds, or drawings based on the real-world.

I’ve written in past posts about 360° panorama photos (360° Panoramas!, More 360° Panoramas!, and 360° Panoramas (again)). In a 360° panorama, the camera (the viewer) is at a single location looking out on the world. Today, we will visit what seems to be the opposite situation.

3D models are created by taking a series of photos of an object from many different directions. The object could be something small, like a sculpture. Or something large, like a movie set. Or something in between, like a building. The camera could be mounted on a tripod and the small model turned to different positions, or the camera could be moved around the small model to take many different views. For an even larger model, the camera could be carried by a drone, for instance, and moved around a very large area to take many images.

I’ve played with 3D models a bit over the last few years. Once you have acquired images of your target, they must be processed in some way to create a 3D object, usually a “mesh” of many triangles that simulate the original model. Much of the software to do this is relatively expensive (hundreds or thousands of dollars), or rented by the month. However, not all software is expensive. After looking at other options, I found Open Drone Map (or ODM). The original purpose of ODM apparently was to create maps and/or models from photos taken from a drone. However, the software doesn’t really care whether the camera was on a drone, or handheld, or on a tripod.

Using ODM, I was able to successfully process several sets of photographs I have accumulated over the last few years. My smallest models were created from about 40 photos shot with my cell phone and the largest I’ve created so far used a couple hundred photos shot with a drone. People successfully use ODM with 5,000+ photos, although that may take days to process, even on a powerful computer.

Once you have created a 3D model you must use special software to view it. Surprisingly, current versions of Windows do come with a simple 3D viewer, but it doesn’t seem to be very robust. There are also websites where the 3D model can be uploaded, then you can view the model with a web browser.

Below is one of the first models I created. It is a tabletop scene of a small wood manger. This model was created from 48 photos shot with my DSLR as I walked around the table, taking photos at different heights to be sure everything was visible. Click the “play” button, wait for it to load, then use your mouse left button spin the model around on your screen, and your mouse scroll wheel to zoom in and out. To see the model full screen, press the “f” key. (I recommend trying that – press the “f” key again to exit full screen mode.)

The photo below is one of the 48 photos that make up the model above.

Tabletop Manger Model – Click to view in Sketchfab

Another 3D model I created is an interesting rock at the entrance to the Arizona-Sonora Desert Museum (ASDM). This one is created from 40 photos I shot with my cell phone as I walked around it several times.

I used several other programs to generate all of the models shown here. First is WSL – Windows Subsystem for Linux. The version of ODM I used runs on Linux, so this allowed me to run it in a Linux environment on my Windows computer. I used Blender to clean up (remove) the extraneous parts of the 3D images, which were then uploaded to Sketchfab. Other programs played more minor roles. Expect to see more about Blender in this blog in the future.