Best or most appropriate software for a 3D model 'walkthrough' of a plant?

[Ste1978]

What software could I use to show off a 3D walkthrough of a water treatment plant I am modelling?

 

I do have a trial version of Navisworks which is ok, but I am looking for something that our client could possibly load up on their computers, possible freeware? I was thinking maybe google sketchup could do the job but it might run a bit slow if I use point cloud data. Any idea?

[SLW210]

Blender might be worth giving a try. http://www.blender.org/

[Jacko93]

In my experience, Navisworks is one of the best for this. Your client can use a copy of Navis works Freedom, which is a freeware viewer for navisworks files, meaning thta they can fly though the model at their own leisure, controlling the flythrough themsleves.