The older page shows that realtime 3D is an important aspect in the art of Block 4. And indeed, not only interactive installations benefits from the usage, also live concerts are augmented with graphics. Reason for choosing realtime graphics over a VJ approach is the better control and synchonisation of content with music. In the early 90s Notstandskomitee used a lot of non realtime 3D animations as background visuals for live performances but now Malte Steiner uses open source game frameworks and include Midi and OSC connectivity to control objects by Midisequencers and -devices. Coming from a visual arts background he never lost the idea of the Gesamtkunstwerk.
While Elektronengehirn, Notstandskomitee and 31101 Orchester involve visuals done with custom OpenGL software on Linux since 2006, Notstandskomitee uses since 2007 an application done with the engine Ogre in the live perfomance set. While there is more control in writing software with C/C++ and OpenGL from scratch, a lot of visual effects like shadows or physical simulations can be archieved faster with a gameframework, which btw. still need quite some coding. This first approach was performed at Piksel festival 2007 in Bergen and Linux Audio Conference 2008 in Cologne.
A recent change in the live hardware made it necessary to change the 3D engine. While Ogre runs very well with Nvidia GPUs it didn't run very well with the Intel GMA 965 X3100 in the new notebook used for performances. A lot of Demos crashes in recent version 1.4.7, leaving a bad taste, particular considering going on stage with it.
So a new and maybe less demanding solution is necessary to find. The site http://www.devmaster.net/engines gives a good overview of commercial and free 3D game engines. The Irrlicht engine is very promising and offer a nice featureset which runs well on the given hardware. Even a good softwarerenderer is provided so hardware acceleration is not necessary at all. Some quick demos were programmed easily and even physic simulation with ODE is not difficult to add. Following are two screenshots done with Irrlicht:
The first one has the smearing motion blur effect and shows its models as wireframe:
two gear models, one semi transparent and one with wireframe overlay:
Everything perfect although shadows are missing. Irrlicht doesn't implement shadow mapping which would work with the Intel graphic chip, only volume shadows. A quick search shows that there is a fork called Lightfeather offering some more features apart from a working shadow solution. Exciting is the morph animation which morphs between to models with the same amount of vertices. Usually a skeletal approach is implemented and available in Lightfeather too, which might be preferable for character animation but deforming/ tweening models is preferred in these projects.