5B: 3D Theory and Algorithmic Modeling

Manual 3D modeling techniques are very effective and have had a long history of producing impressive digital humanities projects.  Lisa Snyder’s long-running project to recreate the World’s Columbian Exposition of 1863 in Chicago is a prime example of what these techniques can accomplish in skilled hands.

1863 World's Columbian Exposition

 

Increasingly, however, computers are doing more of the heavy lifting and there are several methods of generating 3D models that rely on algorithms to create geometric meshes that are being adopted for DH projects.


Procedural Modeling

This term refers to the generation of complex geometry from basic shapes through the application of code-based rules.  The leading platform for this type of work in DH is CityEngine, owned by ESRI, the makers of ArcGIS.  This technique allows a user to produce, modify and update large, textured models of entire cities quickly and iteratively.  The output can be explored online or integrated with gaming software or 3D animation packages to produce video games, simulations and movies.

This software was developed for modern city planners and urban architects, but has increasingly been put to use on historic landscapes and built environments, as in the impressive work of Marie Saldaña who developed a Roman temple rule set.

CE workflow, Marie Saldana

We will explore this technique briefly using CityEngine on the lab computers.

  • Download the zipped file of Carleton College buildings at the link below (or from our Google Drive shared folder) and choose “Import Zipped Project into Workspace” from the File menu to get started.

Photogrammetry

Photogrammetry is another algorithmic modeling technique that consists of taking multiple overlapping photographs and deriving measurements from them to create 3D models of objects or scenes.  The basic principle is quite similar to the way many cameras these days allow you to create a panorama by stitching together overlapping photographs into a 2D mosaic.  Photogrammetry takes the concept one step further by using the position of the camera as it moves through 3D space to estimate X, Y and Z coordinates for each pixel of the original image; for that it is also known as structure from motion or SfM.

Photogrammetry can be used to make highly accurate and realistically photo textured models of buildings, archaeological sites, landscapes (if the images are taken from the air) and objects.  Close range photogrammetry of historical objects offers the possibility of both digitally preserving artifacts before they may be lost or damaged, and of allowing a whole suite of digital measurements, manipulations and other analyses to be performed that allow insights into the material that might not be visible to the naked eye.  The technique is gaining in popularity and usage, since it produces very impressive results comparable to high end laser scanning technologies for a mere fraction of the cost.

  • We will learn this technique using PhotoScan, the leading photogrammetry software. A demo mode is available for free that will let you try everything except exporting and saving your model. If you want to explore more, they offer a 30-day free trial of the full Standard or full Professional editions.

Follow the instructions in the Photogrammetry with PhotoScan Tutorial document.

For data, you can take your own photos, or download the sample dataset by click on the image below:

west stow sub

A reconstructed house at West Stow Anglo-Saxon Village


Blog Post

Write a blog post considering the various ways to make a 3D model and the appropriateness of method to a project.

  • For which research questions would 3D modeling and simulation  be an appropriate methodology?
  • When would manual modeling make the most sense? Procedural modeling? Scanning? Photogrammetry?  A combination of the above?
  • Consider the projects mentioned in the readings for this week and choose one DH project to discuss critically as an example of what can be achieved and what still needs improvement.

 


RESOURCES:

Sketchfab is the leading location for sharing and displaying 3D models

You can register for a free account and upload any 3D content you generate to explore, put in a VR viewer, or share on the web.

More SketchUp Photo Modeling

BEFORE YOU DO ANYTHING ELSE, read through this list of 10 tips every SketchUp modeler should know at masterSketchUp.com Trust me, you’ll be glad you did.

We went over the basics of the match photo technique in class and I linked to some of these resources on post 5A, but here are my recommended resources for getting this technique down.

An oldy but a goody…

These two videos are several years old, but give you some best practices and will reiterate the basic technique.

And here’s a static handout that lists the main steps using the same project: Match Photo: Modeling from Photos

More advanced techniques: multiple photos

The two videos below are more recent match photo  tutorials that show how to incorporate multiple photos, but skip over some of the basic steps outlined above.

And if you want to go deep…

Here’s a four part tutorial that incorporates some much more advanced features.

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