by Dennis Collin
I recently had a question on how to split a large floor slab into different elements so that each part could be in a different model. Obviously, this requires the slabs to be actual different entities therefore the usual answer like using the split face tool or parts doesn’t apply.
Fig 1. Is it possible to ‘slice’ this slab into two, without disrupting the modified geometry?
This scenario related to a large site model where different portions of the site needed a local section of slab to reside in a particular model. When the floor was created originally it was modelled as a single entity before the need for multiple segments across multiple files was considered.
Fig 2. Whilst elements like walls, beams and pipes can be split, floor slabs cannot be divided in the same way.
Elements like walls, beams and pipes can all be segmented using the Split modify tool. Unfortunately, this function doesn’t work with slab objects such as floors, foundation slabs or roofs. This is further complicated when floors or roof have sub-object modifiers applied to allow for slope and water run off etc. Which is typical when working with Revit in a site modelling context. Simply editing the sketch can cause the resultant slab to lose essential height information.
Fig 3. Plan view of the slab to split.
In the example image above, a slab has been modelled with some split lines and vertices added to provide a ridge on a slab, but the requirement is to break the slab into two at a specific point and place each half of the slab into different models. The split edge needs to be precisely cut to ensure no gaps result when the files are linked together into a master model. A reference plane object is used to represent the line of cut.
Fig 4. The split line is used to maintain the sloped slab’s geometric integrity.
The first step is to add a split line feature along the dividing reference plane, the split line will automatically add vertices and edges to adapt to the deformed slab.
Fig 5. The copy and paste function are very useful when modelling slabs and toposolid entities.
Next the slab is copied to clipboard and paste aligned to the same place. Acknowledge Revit’s warning of elements overlapping and the double counting in schedules warning.
Fig 6. Adjusting the perimeter of the right-hand portion of slab.
Select one of the slabs and choose edit boundary. Adjust the sketch lines to form the right-hand portion of the divided slab and click finish. Try and use commands like Align or Move to keep the original linework if the modifications result in severe geometric distortion.
Now modify the left-hand slab and adjust the sketch, in a similar manner and click finish when done. The end result should be the slab split along the reference plane with the position of the edge creases preserved from the original slab.
Fig 7. The end result with the deformed slab being neatly split into two!
If the dividing boundary is more complex in nature this concept will still work, it’s just the modification of the respective sketch edges will be more complex, and more split lines may be required to maintain geometric integrity of the original object e.g. Think of a typical jigsaw piece or the classic Ying-Yang illustration.
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