5B: 3D Theory and Algorithmic Modeling

CE workflow, Marie Saldana

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.

5A: 3D Modeling and Simulation

This week we are going to dive into the archives and explore 3D modeling through Carleton’s buildings..

START HERE: Library Course Guide for IDSC 130: Hacking the Humanities

They have also provided us with guidance on how to translate the metadata found in the archives into the standard Dublin Core metadata schema employed by Omeka.  We will eventually be building a collection in an Omeka site, but IT is still setting up our server so we’ll start (as many good DH projects do) gathering data on a simple spreadsheet that you should have access to in Google Drive.

Metadata Guidelines for Dublin Core to consult as you gather information for our project

 


 Assignment

You are each going to choose a campus building and try to model in SketchUp.

Once you have chosen a building do the following:

  1. Search all the different archival databases to find as many images of your physical building as you can find and start moving them into a database (spreadsheet).
    1. Data Entry Spreadsheet for first pass of data gathering.
    2. Go to File > Make a Copy and enter your data on your own instance.
  2. Find the earliest photos you can that give you a viewpoint on two perpendicular faces of the building and use them to create a new Photo Match model in SketchUp (See instructions below)

As always, post your progress on your blog to share updates and thoughts on your process, or hit the comments section on the course site if you have any questions.

 


 Advanced SketchUp

https://drive.google.com/open?id=0B2hmtN4qlyF1cU5CbWZoeW5LWlE

Resources

We will be using SketchUp’s Match Photo technique to create our models of historic buildings on Carleton’s campus, which we went over together briefly in class.  The clearest step-by-step introduction I’ve found to the Match Photo technique of geomodeling is several years old but the basic principles still apply.  The first link takes you to step-by-step instructions for the process using a photo of a barn as an example, and the next two link to videos walking through the same example.

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.

The other method often used to model existing buildings is the “Extruded Footprint” technique, which has the benefit of georeferencing your model with Google Earth from the outset.  If your building is still standing and visible in Google satellite imagery, then this method might work as a starting point for you, but it won’t provide the level of detail we want unless you combine it with matched photos to add the photo textures and architectural elements.  The video below offers an excellent introduction to how these two techniques can be combined to produce an accurate model, in the same way we practiced together in class.

We are primarily interested in exteriors for this class, but if you find floor plans or architectural blue prints for your building in the archives and want to go nuts and try to start modeling a version with the interior walls, go for it.  Here are a few basic resources to get you started.

Finally, masterSketchUp.com has compiled a handy list of 10 tips every SketchUp modeler should know.