If a family is cuttable then the family displays as cut when the cut plane of a view intersects that family in all types of views.
In Family Editor, click to open Element Visibility Settings dialog. There is an option called When cut in Plan/RCP. (RCP is short for Reflected Ceiling Plan)
This option determines if family geometry is shown when the cut plane intersects that family. Family can be cuttable only if it’s Category is cuttable. How can we know which Revit categories are cuttable and which are not?
Answer is very simple, just take a look at Object Styles dialog or Visibility / Graphic Overrides dialogs in Revit. If Cut column of a category is grayed out means that category is “non-cuttable” (and vice-versa).
Click on the image below for full list of Visibility / Graphic Overrides table.
Ok, so what do we do if we want to make non-cuttable family category cuttable? Well, it is not possible to make non-cuttable family cuttable directly BUT we can use a simple tricks to override this. Main logic behind trick is to nest shared cuttable family into non-cuttable family.
Trick no. 1 For instance, “Furniture” family category is not cuttable. We want to make our kitchen chair cuttable (for whatever the reason). What do we need to do is to create our chair as “Generic Model” family, check it’s “Shared” option, then, insert this family into “Furniture” family. That’s it!
- Pros: We can get cuttable elements even in non-cuttable categories.
- Cons: Visibility controls are done for the nested category, in our example, we must adjust Generic Model category, not the Furniture category. Because of the “Shared” parameter, we will get additional family (familes) in our project model.
Trick no. 2 is if we use cuttable family (for instance: window) and we insert window frame as nested family (Generic Model or of some other cuttable category) we will always get floor plan projection of a nested family instance even if we cut through it. The trick here is to convert nested family from Generic Model category to main category, in this case into Windows category to get desired effect (desired effect is to be cuttable). This way, nested window frame will be encapsulated as an external block (which is easier to maintain/work with) while keeping all of the properties as it was modelled directly inside window family.