Family for Caisson monolithic floor in Revit

[dedperded2025]

Good afternoon!
There was a need to draw in Revit in a building of a monolithic frame type - a monolithic inter-storey ceiling of the Caisson type. (as in the photo) With the subsequent release of specifications for materials and sending the model for strength calculation in CAD.
According to the design of the column with a step of 6x6m, 6x9m, 9x9m along the perimeter of the columns there is no caisson! The caisson is only inside the span.

Can you tell me how this can be done? or are there already ready-made families of caisson-type overlappings in Revit?

[dedperded2025]

Can't anyone help?

[RDAOU]

@dedperded2025 

There are several ways, which is more suitable depends on what is more convenient for your structural engineer

1. Easiest which doesn't require much Revit skills is to place a normal structural slab and use a floor based void array to cut it with 
2. Alternatively you can model that as part of a Beam/Structural Framing family then use that to create a Beam system
3. Another way is to model it as a Pattern Based generic model and apply to a patterned surface
4. An alternative to pattern based generic model is to use an adaptive generic model and repeat it on a divided surface

For each of the above you should be able to find tutorial on youtube... maybe not for a Caisson/Waffle/Girder or whatever you want to call it, but for the workflow in general how to model such elements 

[constantin.stroescu]

not exactly on your problem... but here is a Family of a prestressed concrete caisson that I've made for an industrial building... in my case I 've made a Structural Framing Family using extrusion and a Void . The Roof was made by using Beam System with Layout Rule>Clear Spacing equal with 0 ( in fact not quite equal...)

[dedperded2025]

So I say that my problem is of a different nature. I have a replacement formwork of different sizes for caisson concrete floors. I need to create a family in Revit so that it is possible to change the size of the caisson cell according to a given list of sizes.

[RDAOU]

@dedperded2025 

Did you read the replies above? If yes, may I ask if you know how to model a waffle slab using any of the listed methods or are you looking for someone to model it for you or give you ?

I'm only asking because the Caisson Voids can simply be an arrayed parametric void in a Floor based Family. With moderate revit experience you should be able to model that

[dedperded2025]

I love smart guys! If I could do this, I wouldn't be asking for help from the community! You must understand that!

And if you are so smart, then do it and show me in detail how to do it! And I also know how to write about possible methods and read the manual! It's not pretty!
If you are a professional, then show it!

[constantin.stroescu · Accepted solution]

Parametric Void Floor Based Family - attached in R2022 version

CAISSON | Revit Products 2022 | Autodesk Knowledge Network

....and , please accept an advice that comes from an old guy: the participation on forum is not a contest with prizes, and I don't think we have to be treated like schoolchildren.

[dedperded2025]

Thank you very much. I study in detail!

[dedperded2025]

Tell me, please. This floor model with caissons can then be filled with rebar and the model calculated for the loads? Or is it just a visual aid - a floor slab with squeezed caissons.

[constantin.stroescu]

What I can tell for sure is that the carvings are real so that the volume of material updates in Schedules when these families are used...

Export to CAD can be done both as Polyface Mesh and Solid, also.

As long as I'm not a structural engineer and I'm not accustom with reinforcement procedure in Revit I'm not able to appreciate how tis works...

[dedperded2025]

Thank you very much.

[lucdoucet_msdl]

I would expect the Revit Structure Forum would be the appropriate forum to follow-up on the details involving how to model and calculate structural elements. They may even propose alternative modelling techniques.

-luc

[Marie.j03]

Thank you for the family you attached and the detailed explanation  constantin.stroescu