Alert! WC on Plumbing Wall


We usually don’t pay much attention when placing a water closet in a toilet room.  This may end up with WCs that are placed on walls not thick enough for plumbing and drainage.  Here is a tool that can alert you when the wall is too thin to host a WC, the exclaimation mark will pop up to remind you to change the wall type.

WC-ALERTSo if the requirement for the minimum wall thickness for plumbing is 6″, any WC hosted by a wall thinner than 6″ will have this red exclaimation mark.  This is a trick played on the toilet family.


The toilet family is a wall hosted family.  The thickness of the host wall can be made as a reporting parameter so that the family can know how thick the wall hosting it in the project.  Thus other geometry can be driven by the reporting parameter.  The concept is: if the reporting parameter (wall thickness) is less than the minium thickness of plumbing wall (for example 6″), a geometry (alert symbol) will show up otherwise it will not.

1st Attempt

Starting with a wall hosted toilet, I created an extrusion (1/32″ high) of an exclaimation mark right next to the toilet.  I dimensioned 2 reference planes which were locked to the outside and inside face of the host wall and then turn the dimension into a reporting parameter “Wall Thickness”.


I was thinking using simple visibilty parameter to control the alert symbol and by means of a conditional statement with Wall Thickness (reporting parameter) less than the Minimum Plumbing Wall Thickness (6″) making the symbol visible.


However Revit gave an error when using the reporting parameter in the formula.



Thanks Alfredo Medina for his comment.  For family creation, we usually dimension reference planes or reference line to create parameters and then lock the object to the reference planes or reference lines.  However in the case of reporting parameter, it should be dimensioning face of the host wall, not reference planes locked to the wall.  By dimensioning the host wall as reporting parameter, the conditional statememt controlling the visibilty of the alert symbol can work now.

Other Solution

There are ways other than visibilty parameter to control an object to show up or not.  If an object is totally cut by a void, it will be invisible.  If the void is not touching the object, it will remain uncut and visible.   I was thinking a void with variable height that when it is long enough to cut the entire exclaimation mark, the symbol will be invisible.  If the void cut is short, the exclaimation mark is not totally cut and it will remain visible.  A void extrusion was made starting at a reference plane at Minimum Plumbing Wall Thickness above the reference level.  The depth of the void extrusion (downward) was equal to the Wall Thickness (reporting parameter).  Thus if the void extrusion equals or exceeds the Wall Thickness, it will touch or go beyond the reference level and cut the entire alert symbol.



3 responses to “Alert! WC on Plumbing Wall

  1. Hello, Kelvin. The error happens because you created the reporting dimension between the reference planes, as shown in your illustration. If you measure just the two faces of the wall, the formula will work.

  2. Pingback: Automatically Run API Code When Your Model Changes (Does this toilet make my wall look thin?) « Boost Your BIM – making Revit even better·

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