There is no (usable) direct import in Unity from ArchiCAD models. You can export to 3ds from ArchiCAD and load that, but it is advised to use the FBX format (and in second order of usefulness) the Collada DAE format.
Realtime GI and screen space Ambient Occlusion can easily get you better lighting and visual depth, but this is clearly targeted at Desktop applications. Mobile devices, especially those who are not very recent, struggle with the very high polygon counts of ArchiCAD models and having real-time shadows, GI and these screen effects, is simply too much.
Pre-rendering the lighting into textures is an alternative, but for some reason, it takes even longer with Unity 5 than it did with Unity 4, as the technique used is quite different.
ArchiCAD models however often struggle from following problems:
-- too high polygon counts (lots of geometry that you need in the model, but that is never seen in a visualisation)
-- UV-errors - they often enter when transferring an ArchiCAD model to Cinema 4D. It is possible to correct them with proper UV-editing (not scaling/tiling of the Texture tag, but actually scaling the UV gizmo)
-- recreating or regrouping some geometry e.g. if you want to open the door leaf in Unity, but not the door frame. It is possible, but takes effort.
My experience is mixed: too heavy for my iPad and iPhone, usable on my Mac or on a PC with realtime, but far from the clean and realistic looking AAA games you might be referring too.
If all you need is realtime walkthrough and having object Info attached, BIMx surely is usable. For any custom interaction or scripting (e.g. parsing schedules, having animated opening doors, changing lighting, having a visible player...) you can use Unity (or Unreal or CryEngine or ...).
--- stefan boeykens --- bim-expert-architect-engineer-musician ---
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Archicad-user since 1998
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