In-Class Exercise: Choose your own Photogrammetry Adventure
There are an increasing number of methods for creating photogrammetry models in the market, and we are going to experiment with several of them and compare the results. Some of these methods require dedicated local hardware with lots of RAM and advanced graphics processing capabilities, others are cloud-based which offer speed and ease of use at the cost of some control over your data and the details of the process.
We will explore the following methods for creating photogrammetric models:
- Agisoft MetaShape (the venerable desktop-based solution to process photos)
- Autodesk ReCap Photo (a cloud-based solution run from the desktop that integrates with other Autodesk offerings)
- Scaniverse (an app that leverages the latest camera and LiDAR scanner technology of iOS devices)
- Polycam (an app that works on any phone and can use photos or LiDAR to process and edit models)
You will form groups around an object, and each member of the group will try a different method. Some of these are quicker than others, and we will compare and clean up the results in class next week to share the best models with the Archives.
1) Using Phone Apps
- You’ve already tried this method.
- There are pros and cons between ease of use and lack of customizability and export options without pay
- These apps will process the models live and allow you to share and export results almost immediately
1) Taking Photos for Photogrammetry
- Hopefully you have already taken photographs of your building
- If so, upload them to the Building Data photo of the google drive shared folder
- If not, you can use this sample image set of the Northfield Depot
The most important step in photogrammetry is collecting data: i.e. taking good photographs that will have sufficient information for the algorithms to stitch images together and extract 3D geometry from them.
With a mobile phone camera, you’ll want to make sure you follow these guidelines:
3) Processing Photos (can be completed in class Thursday)
MetaShape (Mac or Windows)
A demo mode of MetaShape 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, but the software is very expensive after that.
Processing Photos
The main steps in the MetaShape workflow are:
- Add photos
- Align Photos
- Build Dense Cloud
- Build Mesh
- Build Tetxure
- Inspect and clean
- Export to desired format(s)
Follow the instructions in the tutorial below
For more, Agisoft has excellent tutorials on their website that stay up to date with advances in the software.
Autodesk ReCap Pro (Windows)
ReCap Photo is a good solution for Windows, as a cloud-based photogrammetry software that is part of the Autodesk suite (along with Fusion360), but can be finicky to install.
- Make sure you are logged into Windows on your lab computer or download to a Windows laptop (the software does not work on MacOS)
- Go to the Autodesk Education site, login to your account, and Download ReCap Pro software.
- You’ll also need to download and install the Autodesk Desktop Connector software for Windows
- Make sure the checkbox is checked to also install Recap Photo (see above)
- Launch the Autodesk ReCap Photo software from the desktop (NOT ReCap)
- Sign in top right if not already logged in
Processing Photos
ReCap Photo makes processing easy by handling most of it for you in the cloud. The main steps are:
- Load photos
- Upload to cloud
- Wait for processing
- Download model
- Inspect and clean
- Export to desired format(s)
Follow the instructions in the tutorial linked below:
Lab Assignment (due Sunday):
Your assignment for this week is to compare at least two 3D models of your building to eventually add to our 3D map of campus.
Make a 3D model using photogrammetry
- Use at least two of the methods above
- Export your model to get 2 different versions to save in your Google Drive folder
- An OBJ file (for sharing) by following tutorial instructions
- A GLB file (for online viewing).
- For this, you may need to convert the OBJ file into a gLTF/gLTB file in Blender, following the tutorial instructions
- Save project files and all exports to your building folder in the Common > BuildingData google drive
Write a lab report on your process so far
Reflect on your experiences with the building project so far in light of the readings and examples of photogrammetry and cultural heritage modeling you’ve explored.
- Include an image of your building
- A brief description
- Embed at least one interactive view of the model from an app
- Answer at least two of the questions below
- How does attempting to model a building compare to simply viewing one through photographs or maps?
- Does the process of photogrammetry encourage close looking and attention to details you might otherwise have ignored?
- Does engaging with the built environment in this way make you more curious about this (and/or other) things, as well as the stories they can tell?
- How does moving from passive observer to active modeler change your thinking on communicating about campus, lived experience and history to various publics?
Turn in your assignment
- Submit the link to your post by pasting in the Moodle assignment
Specifications for Sunday’s assignment
Complete Labs must include
- In Google Drive Folder
- All photos taken of building in Google Drive folder
- 3D model file and exports in Google Drive folder
- .obj (+ .mtl and .jpg)
- .glb
- WordPress Post
- lab report that includes
- an image of your building
- A brief description
- An embedded interactive view of the model from an app (e.g. Scaniverse, Polycam, or SketchFab model viewer)
- Answers to at least two of the reflection questions listed above
- lab report that includes
