3D SKETCHUP MODELS

This is a contribution to the Pardee Keynote Symposium entitled “Digital Geology Speed Dating.” At Table 6 we discuss Interactive 3D models, illustrating how geologic structures and concepts can be created with Trimble SketchUp. The free version of this program allows for importing USGS DEM and DDF format files, which can be used to portray topographic surfaces that can be draped with geological maps, and coupled with accurately located cross-sections. SketchUp can also help produce models illustrating how planes and more complex surfaces structures intersect topography. SketchUp models can show in detail how to solve the three-point problem and how down-plunge projections work. Interactive block diagrams illustrating contact and crosscutting relationships can help students in introductory and structural geology courses grasp fundamental concepts in geology.

Cross-sections and models produced with SketchUp can be geolocated and exported to Google Earth as Collada files to give the 3-D models greater geographic context. Accurately located cross-sections can be elevated above the ground surface. SketchUp models in Google Earth can be attributed with added user-interaction using the Keyhole Markup Language (KML) TimeSpan element and the Google Earth Time Slider. It is also possible to make the ground surface transparent to reveal sections in the subsurface and integrate them with geologic maps. 3-D models of real folds and faults created with SketchUp can be precisely located in Google Earth to give virtual field trips greater authenticity. The free version of SketchUp presents educators with a valuable teaching resource with which to engage students in tasks that encourage the visualization and consideration of 3-D geometries.

The professional version of SketchUp offers the ability to create dynamic components, which are available for everyone to use in the free version. Dynamic components add another level of interactivity to SketchUp models. For example, models illustrating how the stereographic projection works can incorporate dynamic components so that the user can specify any values of strike and dip or trend and plunge to explore how planes and lines will plot on the stereonet.