Geological modelling is the ability to create computerized representations of subsurface geology. Many times, every once in a while, I have searched internet to find nice-looking geological models, just to find ideas or whatever the workers were doing. I like the ones with many colours (using all-the-rainbow) with a 3d immersive-perspective, nice vertical and horizontal axis lines and a 3d north-arrow. The idea of being true or just being a well-documented cartoon of something real was not important at the first point. For most geologists a nice looking 3d geological model is supposed to be truer than a simple map.

Then the next search is about the new accepted manuscripts of recently published papers in some scholarly journals, academic journals, to see what was new about illustrating works. My filling and also of my staff companions are that nice-looking figures illustrating a geological manuscript permit a better, faster, less time-consuming publish research results. All of us remember some not top-quality (debatable quality) works published because they have awesome figures.

Well, now we known the interest of geological modelling but most of the time what we need just a geoscience art-work.

A geological model can be obtained after doing three phases, that can produce each one a geological 3d illustration, and can be considered a computerized subsurface geological representation.

• The first level is the geological 3D sketch in this level show a simplistic way of showing a complex geology. The software to do so is the kind of a “mudball” modelling software as for instance (sketchup) https://www.sketchup.com/, Blender (https://www.blender.org), or Tinkercad (https://www.tinkercad.com). But taking in an account that we normally like to start with a geological map or an aerial photomosaic (like google Earth). The software must have 2D mapping and mosaic tiles import filters capabilities. As my experience of working with 2D for mapping the best choice is Autocad 3d Map (Autodesk). I can map then, then create surface an made simplistic geological model, what a sketch is.

• The second level is the realistic 3d model representation. In this step we like to integrate the relief, using a Digital Elevation Model (DEM), with the aerial photomosaic, and the information below the land surface. For geological model we like a 3d net used as scale to appreciate the rock volumes. Also, we like a software with capabilities of change the vertical factor and to create immersive perspectives. All this can be done also with Autodesk programs, but it takes a lot of time to produce the model because they are designed for computer-lovers than like to spend days in front of the screen. The final result can be the better one, but geologist usually like to check the results in the field, not spending all the time with the computer. This last reason is that I prefer a simpler graphical interface so do a nice-looking illustration from a point of view of an Earth scientist, not a blockbuster movie. Therefore, my choose is the golden software surfer program.

• The third level is using the realistic model to go back and forth in time to see the deformation history and trying to understand the forces and the deformation phases to produce the 3d geometry. This is the goal of the structural geology. To achieve this level most of the time it has to be a simplified the previous model to work with because some information is useless in this level as for instance the aerial photomosaics. For this phase are designed the principal geomodelling software as for instance Petrel, Gocad or MOVE. All mentioned software is oriented to the petroleum industry so it means that are not cheap. In my case the easier to get access has been the MOVE and that’s my choice.

Finally, the example that I most like is the British Geological Survey model of the Assynt culmination Geologica 3D model that you can download here in a 3D pdf file.

http://nora.nerc.ac.uk/id/eprint/504722/1/Assynt_Culmination.pdf