How I started
When commercial drones became popular, I was immediately fascinated by the opportunity to capture images of a landscape from above and to convert them in a 3D model with the use of photogrammetry. I started to apply this technology by capturing models of certain geological outcrops that I thought were worth sharing. I soon discovered Sketchfab as a very practical platform to share my models with other people. Then I learned to edit my models with Blender, adding elements that would help explain the geological concepts that are present in the outcrop. And finally, I learned the Sketchfab Viewer API, which I use mainly to show or hide each element of the model interactively.
I started to generate 3D models of geological outcrops as a hobby, out of my personal interest. I usually enjoy capturing the outcrops that have already been studied and interpreted. When I render them in 3D, I make a synthesis of the interpretations made by previous authors. Together with the outcrop topography, I try to collect additional elements in the model, like geological maps and sections, and the geometric representation of the geological structures. I build the models for my personal interest, but I believe that they can be appreciated and be helpful also for other interested viewers.
I usually start by capturing images of a geological outcrop with my drone, and then I use Pix4D to convert the images to a 3D model.
Then I import the model into Blender and start adding other elements.
One very important thing is a graphic scale, so that viewers get an immediate feeling of the object scale.
When I can make reference to an existing interpretation, I like to add geological maps and sections that help explain the geology of the outcrop. In the case of maps, I first georeference them using QGIS.
Finally I use BlenderGIS, an addon that allows downloading satellite imagery and topography over a certain region. With the same addon, I can also upload the georeferenced geological maps. In this way, I can include the initial model inside a greater area and give a feeling of the relationship between the outcrop, the real world, and its geological interpretation.
Then I export the model to Sketchfab and prepare the Viewer API code to display it.
I am a big fan of the Viewer API, because it allows people to interact directly with the model.
It also allows me to include many elements in the model, and then switch them on and off depending on the topic I want to display.
The main function that I use are the buttons to switch individual objects on and off.
I have been experimenting also with other functionalities, like:
- moving objects (simulating the displacement of a geological fault)
- changing the texture (to highlight the relief in grayscale or to identify different areas with different colors)
- taking measurements between two points (of distance, height, dip, azimuth)
- moving to specific views (to focus on certain details hidden in the model)
- updating text boxes with explanations or opening a website with more information
Finally, I include the model in a website where I add some background information.
Lately I am also adding a video that shows the model in motion. I find that this is a very quick and attractive way to capture people’s attention and to show all the options and configurations available in the model.
A few examples
Glacial moraine displaced by a fault
This is the model of an outcrop located near the village of Apartaderos, in the province of Mérida, in the Venezuelan Andes. It is the first model that I generated but I have kept on updating it with new details until very recently. I love it because it shows very clearly the influence of geology on landscape. It represents a strike-slip fault in the Venezuelan Andes, that with its movement has displaced a glacial moraine and changed the course of the stream that flows in its valley.
I rendered the movement of the faults by actually splitting the landscape into two halves and shifting the two pieces into four stages of evolution. In each stage, the geometrical objects, representing the stream and the depositional surfaces, change to show the landscape’s evolution, and a text box containing an explanation of the changes is updated.
I flew over this area for the first time in 2015, but when I generated the model I realized that I had failed to capture the top part of the glacial valley. Since I had no opportunity to return to that place, I finally managed to fix the problem when I learned to use the BlenderGIS addon. So I filled the missing part of the landscape with a satellite image that, although it does not have the same definition as the drone images, nevertheless helps to complete the geological feature.
A surface anticline and the associated blind thrust underneath
This is the model of an outcrop located by the village of Viana de Jadraque, in the province of Guadalajara, in central Spain. I visited it for the first time in June 2019, with a group of geologists of the Spanish association AGGEP (Asociación de Geólogos y Geofísicos Españoles del Petróleo), offering them the opportunity to experience how to use a drone to make a 3D model. I had chosen this outcrop because it was easy to access with the group and it represented a simple but clear geological feature, namely a plunging anticline. During that excursion, we flew the drone, acquired the images, generated the 3D model and added a geometrical surface representing the anticline, and the group was very happy with this experience.
Some time later, I realized that the geological interpretation of the area included a geological feature present in the subsurface, underneath the anticline and responsible for its formation, namely a blind thrust fault. So I updated the model, adding the map and section from the geological interpretation, and creating the geological surfaces representing the fault and the deformed horizons in the subsurface. In this way, the model has become a very instructive example of the relationship between a geological feature hidden in the subsurface and its expression in the surface geology.
Virtual field trip and 3D printed models for a student’s experience
This is a set of models that I captured from outcrops located near the village of Riba de Santiuste, in the province of Guadalajara, in central Spain. I prepared them to help document a geological field trip that was part of a course in the UAM (Universidad Autónoma de Madrid). The project (UAM project C_018_20_INN) was coordinated by professors Belén Oliva Urcia and Miguel Gómez-Heras and consisted in preparing a virtual version of the actual field trip, so that the students could become familiar with the outcrops before actually visiting them, and could revisit them at their leisure after having seen them in real life.
The whole virtual field trip consisted of a number of 3D models on Sketchfab, both at regional and outcrop scale, and a number of 360º panorama pictures, captured by the professors and uploaded to Roundme. The regional model was useful to represent the big picture, showing the surface evidence of the large anticlinal feature that exists in this area. The other 3D models and the 360º panoramas focused on specific outcrop features.
Two of these models were reproduced in a certain number of copies with a 3D printer and handed over to the students during the field trip. This was an additional tool to help them visualize the large-scale geology of the area.
Rendering a church demolished a century ago
This model is not related to geology, but rather to a historical monument. It represents the ancient church of San Salvatore that existed in my hometown (Piacenza, Italy), but was demolished in 1923.
I came to know of this church during a guided tour and soon I had the desire to reproduce its appearance. Luckily, I found several documents containing church plans and pictures, which allowed me to rebuild the church structure and its location with respect to the present day buildings.
In this case I also used QGIS to georeference the church plans before uploading them into Blender. I continued using Blender to build the rest of the monument, making reference to the plans and pictures to estimate the shape and size of external and internal structures. And I included a picture of the façade to add a bit more realism to the model.
It was rather interesting at this point to discover that the façade of a present-day building, which used to lean against the church, still contains the remains of an arch that belonged almost certainly to the church itself. Since the model has become rather complex, it is not easy to find this feature, so I have added a button that aids in the search and zooms right to this structure.
The future of 3D science
I can speak for my area of interest. I find that 3D science is a very needed and powerful tool to help visualize structures with complex 3D relationships. It applies very well to the need of communicating concepts to non-specialists, especially in the fields that I enjoy studying, like geology and historical heritage.
I think, for instance, of sightseeing tours, where certain explanations can be transmitted more intuitively with a 3D model, rather than with a 2D static panel.
In the case of academic field trips, 3D models allow students to become familiar with the outcrops before actually visiting them. And after the visit, the students can analyze further details, easily viewing the outcrop models from different points of view.
In my experience, Sketchfab is a very practical platform for this purpose, because it allows a large number of people to have access to the models. The Viewer API adds the possibility to interact with the models, providing the opportunity to include many overlapping features that can be switched on and off as needed. These API tools allow several features to be included in the models, making them more informative and interesting to explore.