Showing a setdown is required for producing the structural or concrete plans. As BIM is not a 2d CAD tool, 3d modelling of the floor setdown is expected. Unfortunately, there is no best way to model the slab setdown element as there is no function built-in in Revit. However, there is a workaround. I have seen so many people doing different things to just create the set-down in 3D. They all have pros and cons, and it needs to be implemented depending upon the scale of the project or the team members' Revit skill. In this post, I am going to share the modelling tips about how to create the floor setdown and the consequences.
Use Generic Model for setdown
Basically, you create a generic model which has void only and cut the slab. Then, it will scoop up the floor. Make sure to check the option of ‘cut with voids when loaded.’
Pros
It is easy to create the family as a parametric object and get accurate sizes if it is square/rectangular shape. Moreover, it can be tracked and managed in the schedule.
Cons
You have to cut every time you place the void model although the void cut function is enabled. Moreover, there is a potential issue where the void cannot cut the floor for some random reason. If there is a floor in the same area, it can be an issue. Moreover, there is a limitation to modifying the outline of the model. If the outline is an unusual shape, it is impossible to archive in a generic model.
Use Floor elements for setdown
This is my favourite choice to make the floor setdown. The logic in this method is that you create two slabs overlapped with each other and filter out one of them. It will create the setdown.
Pros
It is easy to control and manage the elements. It looks clean and there will be no additional objects (The method above requires the additional family (void). You can only look after the concrete plans to check the set-down.
Cons
It can be a warning as the idea is overlapping the floors. All view templates should have a filter to display appropriately. Initial set-up takes lots of time. Moreover, someone can forget to join it. It is difficult to select the element once it is joined.
Split Floor elements
I suppose this is the most popular choice for people when they want to create a setdown and it is the most time-consuming method listed here. The method is simple. Model each floor in relation to the slab thickness.
Pros
It is a proper way to do it in my opinion as it will reflect the structural slab thickness.
Cons
Documentation will be BLOODY difficult. Basically, you need to join all the floors or do linework to hide the floor joint. Sometimes, you cannot join the floors for some random reason.
Does Shaft or other openings work?
Some may think of using Shaft or other openings, but I regret to tell you that it does not work. As long as the Shaft or other opening touches the floor, it will penetrate the element. Therefore, it is useless for the set-down.
To sum up
It is important to note that you need to understand the pros and cons of this workflow and make a decision on which method will be used in your project. Changing the method is nearly impossible and risky during the documentation as all the annotations in association with this setdown will be lost (if there are not many areas in the project, then it will be acceptable).
If you have other alternatives to generate the floor setdown, please comment below.
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