https://www.bbc.com/news/science-environment-65602182
Really interesting use of photogrammetry to 3D model the titanic. A student in my digital heritage class was able to create a partial 3D model based on a documentary video.
Category: Digital Heritage
Create 3D Terrain Models from Real World Locations
Software Needed:
QGIS: Geographical Information Software
Adobe Photoshop
Atlas 3D Map Generator (Photoshop plug-in)
I have been creating 3D models of terrain for uploading to SketchFab and also generating 3D models for use in my World Heritage sites class. With GIS, it is possible to add any additional information to the 3D models as needed. I like this approach because it is straightforward to create whatever 3D content you need with just a few clicks. It did take me a while to figure out this workflow, so hopefully this post will save somebody some time and effort.
My General Workflow:
QGIS
- Capture with screenshots digital elevation models (DEMs) and aerial imagery within QGIS. The advantage of this approach is that any other GIS layers can be added on top of the DEM models in the final 3D modeling rendering.
a. Navigate to a real world of interest within QGIS.
b. I typically use the QGIS SRTM plug-in for automatically downloading the DEMs that cover the current extent. If there are more than one DEM, I merge them together.
Raster ⇨Miscellaneous ⇨ Merge. Then add the recently downloaded SRTM files and click merge.
To use this SRTM plug-in, create a free profile at https//urs.earthdata.nasa.gov.
c. Take screenshots of both the DEM and aerial imagery for the overlaying 3D model’s texture. Make sure the screenshots cover the same area of the screen so that they overlay each other.
Photoshop
- Open the DEM raster layer in Photoshop.
- Create a new layer in Photoshop and embed the texture layer (aerial imagery or other GIS layers), and label this new layer as texture.
- Create New Terrain using the Atlas plug-in
- Modify the terrain settings and export the 3D model from Photoshop.
I normally export the 3D model with 600 cm width dimensions which seems to work well with uploading to SketchFab. I also save the texture files as JPEGS which SketchFab can process.
Upload to Sketchfab
- Compress the exported .obj and other supporting files. On a Mac highlight all the files, right-click and then select compress. Upload the .zip file to SketchFab.
Lulz Taz 5 3D printer — A Fused Deposition Modeling (FDM) printer
Changing Z-Axis Home Height
The Z-axis home height is the distance between the bed and the height of the extruder when it is in the home position. This distance is critcally important for determining how well the filament is dispensed from the extruder and deposited on the bed plate. A Z-axis home height that is too high or too low will result in the filament not sticking enough to the build plate or not depositing properly.
Adjust the Z-stop knob counter-clockwise to raise the height of the extruder above the bed, and rotate clockwise to lower the extruder closer to the bed.
The Z-stop should only be adjusted by the lab manager.
The thickness of a single piece of paper between the extruder and bed is normally the correct distance.
This video from Lulzbot demonstrates how to adjust the Z-stop.
I had to adjust the Z-stop recently when I was moving the extruder manually with the LCD control panel, and pushed the extruder into the printer’s bed.
I had been printing PPE equipment for the West Texas region for over a month with no issues.
After this happened the filament was not depositing onto the build plate, and the extruder was positioned right on top of the build plate in the home position. After I readjusted the Z-stop, and created a paper-height difference between the extruder and build plate, the filament began depositing correctly.
Finding the Path of Least Resistance
A positive academic discussion
A paper by Marcos Llobera titled “Memory at your feet: Modeling the agency of past trails” presents a new GIS simulation package, NetSim, to account for the effect of past trails on the movement of people across the landscape.
To walk the same way is to reiterate something deep; to move through the same space the same way is a means of becoming the same person, thinking the same thoughts.
Indeed, knowledge of the landscape through cultural practice is heritage and identity.
While most people would agree that existing paths must have influenced later ones, it remains very challenging to establish the magnitude and scope of such influence in any precise manner.
Very true. I think Llobera’s attempt to simulate the impact of prior trails, however, is an important intellectual step forward beyond just looking at least-cost pathway analysis.
Creating a 3D model of a surface with QGIS
The easiest method I have found for creating a 3D model from a digital elevation model (DEM) is with the QGIS plugin [DEMto3D]. Simply add the DEM into the plugin, and you can adjust the model’s base height, z exaggeration, etc., The model can take awhile to create if the DEM file is large.
The plugin creates a STL file that can then be added into Meshlab or other 3D viewers for further manipulation. The model should also be easy to georeference based on obtaining the extent coordinates within QGIS. The plugin was designed for 3D printing landscapes.
Stancecmac 