Re: modeling depressed slabs
How your doing it is how we do it currently....have heard that some people will add a void to floor based family....but it can be tedious if you have an irregular shape...
Re: modeling depressed slabs
One trick is to align and then lock the 4" slab to the opening in the 6" slab. I've gotten this to work in the past. However you may run into issues with over-constraining. Also the model may have performance issues when editing the slab.
Using 2 slab and joining them is the only way I've heard off. It's also the easiest and least likely to cause major issues in the end.
Of course the other option is to not model it. In the end the floor is going to be flat. In your detail you could simply mask the void. But this gets into that whole question of model sharing. I wouldn't know there was a void there if I just had your model linked. So I guess it's users choice. I've had to many MEP consultants use the excuse "Well they'll just adjust that in the field and I don't have time to redo all my piping routes so....we're just going to leave it where we have it now." Damned if you do, damned if you don't.
Re: modeling depressed slabs
Ditto to your two separate slabs.
Ditto to David's suggestion of locking the edge of the 4" slab to the hole in the 6" slab.
Lucky for me, most of my depressions have been pretty rectangular so far so I haven't run into any "over-constraining" issues.
Re: modeling depressed slabs
That spawns another question I have about locking elements (which I've addressed in another thread).
Thanks all for the input!
Re: modeling depressed slabs
I use a face based void family so it cuts into the floor, but does not generate a new Structural analytical element. For edge like this they are quite easy to move since you do not modify the skecth and break any specific join conditions.
Re: modeling depressed slabs
Is that a custom void family with depth parameters added to it? Revit's built-in face based opening tool just cuts through the whole element with no thickness or depth adjustment (or am I doing something wrong?)
Re: modeling depressed slabs
Yes it is a custom floor based void family.
Be aware if won't affect concrete beams or framing members but will cut through floors. Keep all parameters as instance properties.
Re: modeling depressed slabs
I don't like the idea of modeling two different floors. It has a number of downstream effects that may adversely affect model updating and structural analysis.
In a few of my AU classes, I walk through how to create a slab depression family. It also hatches itself for construction documents.
I think the most complete tutorial is found in this class:
http://au.autodesk.com/?nd=e_class&session_id=5234
Re: modeling depressed slabs
Thanks Steve!! In looking at the lab info, I think I saw the presentation version in AU Virtual at one point. I was only on my first or second Revit project at the time, so I had bigger fish to fry than slab depressions, but it was a great presentation.
Your solution works great for most of my situations. Before I even try, is it possible to make a similar void family that would be sketch based, so you could outline complex shapes? I see that you can hook multiple rectangles together, but I have a couple depressions with angles, 17 corners, etc.