I am engineer surveyor, retired but still developing software for Aker Solution and Kværner Norway
Spent most of my working hours measuring and proccessing data on norwegian onshore/offshore oil&gass plants/platforms.
Started with software design as hobby but "went" professional gradually, due to huge demand for custom applications and plugins.
Software development is ,mostly, connected to proccessing survey data, such as 3D laser scanning data.
One example of finished product of proccesing is 3D CAD model, usually MicroStation but also Autocad and PDMS
I "spaek" VB, C, C++ and c#, use Visual Studio as main tool.
In the context of MicroStation, I have created "surveyor package" for , both, v8i and Connect.
Package is group of applications/plugins, such as modeling tools for piping, steel structures, industrial equipment , pipe elements library with some 8000 3D cells, data import-export from/to external applications, PointCloud computation/modeling tools etc.
Development tools I use are: MicroStationSDK, MDL, the MicroStationAPI, VBA, .NET(any language)
I also use many OpenSources, such as PointCloudLibrary, VTK, Eigen,Flann etc.