modeling depressed slabs

[trialbyfire]

How are you modeling depressed slabs? For example, where you have a 6" slab, and want to show a 2" depression for tile at a bathroom, etc. (I'm not worried about modeling the slope for any drains - I usually just detail line that part).

Modeling a 6" slab with a hole in it, and then modeling a 4" slab separately at that area is a drag because every time it needs adjusting (which is often) twice as much editing is required.

I was thinking there was a way to create a partial void that I could embed just a little bit into the slab (model the slab full thickness and then just 'void' out the depressed area), but everything I'm seeing cuts out the entire thickness of the floor, not just the top two inches.....?

[cdatechguy]

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...

[david_peterson]

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.

[lzaras]

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.

[trialbyfire]

That spawns another question I have about locking elements (which I've addressed in another thread).

Thanks all for the input!

[m20roxxers]

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.

[Baghera]

It's a shame you can't put a reveal in the floor. That's what I do for beam pockets