Physical Computing and Fabrication

What is photogrammetry?

From Wikipedia: “Photogrammetry is the science of making measurements from photographs, especially for recovering the exact positions of surface points.”

With a camera, you’ll take a series of 2D images and use them to measure the distance between certain points on your object in order to create a 3D model. The photographs will be captured from different positions and angles around your object. Then, using Agisoft Photoscan, we’ll stitch together chunks of 2D images into 3D meshes with texture.

Things to remember while taking your photographs:

Photoscan workflow in short:

  1. Add cameras
  2. Align cameras
  3. Generate dense cloud
  4. Build mesh
  5. Add texture

Photoscan Workflow in detail:

Photoscan workflow in action:

The first step in the Photoscan process is photo alignment, where you pinpoint areas that need more or less focus. Here, you can experiment with different combinations of camera points to achieve your desired collection of photographs. This step is especially useful when Photoscan attempts to absorb unwanted sections/objects of your photographs into the model (like other objects in the frame, walls, patterns, harsh light spots, etc).

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In the second step, you’re going to build a dense point cloud, where you resize or rotate sections of your object. This step is useful if a particular section of the model has been detached or is the wrong size. If you like, you can also take this opportunity to alter your model. Rather than attempting to directly replicate your original object, you can rearrange, resize, or flip different sections to modify your model.

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Next, you’ll build a mesh and Photoscan will adapt your changes into an accurate model.

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Finally, it’s time to add texture. This step adds texture onto the surface of your modelled object and your mesh begins to look like a thing.

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Modify your model:

After you get acquainted with Agisoft and have created a couple of models using unaltered photographs, you might want to start thinking about ways to alter your model by digitally manipulating your images. Before running your photographs through the program, consider modifying your images with photo editing software. Any photo editing software will allow you to play with the contrast levels, brightness, and colour. If you want to edit your photographs further, you can use Photoshop (or a similar program) to completely rework your model. For example, you can add or subtract details, distort the image, play around with colouring/brightness/photo quality, add sections of another image to your images, etc.