BIM and Virtual Reality - Visualization in demanding conditions

BIM visualiation is demanding due tothe large number of objects on screen. According to this paper "Real-time visualization of building information models (BIM) - Current state vs. state-of-the-art" by Mikael Johansson and Mattias Roupé we have three strategies to accelerate:

1. GPUcentric optimizations - maximize the raw processing power of modern GPUs. E.g. arrange the draw-order of objects by material properties to minimize state changes. It is not indefenitable scalable. 
2. Level-of-detail - reduce the complexity of a 3D object representation when the object is far away from the current viewpoint, but who produces the simplified models?
3. Visibility culling - only sending objects that are potentially visible to the GPU. Two kinds of culling:
1. frustum culling, where objects are discarded if they are found to be outside the visible region of space, as defined by the virtual camera
3. occlusion culling the: discard objects that are guaranteed to be hidden in the final image. Harder to implement but very efficient in buildings

This paper compared performance for the three viewers and they are all bad:

• Tekla BimSight
• Autodesk Navisworks
• Solibri Model Viewer (the best by far).