3D images give underground view for distribution of soil properties and show anomalies in result of GPR surveys.
You can draw shapes of supposed objects, pipes, etc.
The Visualization Toolkit (VTK) is an open-source, freely available software system
for 3D computer graphics, modeling, image processing, volume rendering, scientific visualization, and information visualization.
ParaView is an open-source, multi-platform data analysis and visualization application.