Thanks for all the suggestions.
I've tested it out and the beam works perfectly in regards to choosing which floors to show it on.
there is on problem however. It is important that the channels are 'cut' into the ground floor, and so I've been using solid elements operations. (It took over 2 hours as I had to do each piece separately. Trying to cut multiple pieces makes the floor slab 'disappear'!
The main problems is that although the slab appear on ground floor, it does not appear in 3D. I've checked all the options such as filtered elements, but it won't show up.
I've attached a screenshot of the channels and, as you can see, they are lots! (It's a rail-served automated distribution centre, with a distance of 500m)
Would there be another way of creating this, or at least fixing the issue of not having the ground floor show up in 3d.
Thank you very much.
Nathan
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