Families Flex without dimension labels?

[Anonymous]

Hi

On looking at Revit MEP supplied content (air terminals) the model will still flex when parameters are changed, but there seems to be no linking of the parameters to the model via labelled dimensions, how can this be. For example:

Looking at an extract grille or supply diffuser, under the Family Types dialogue->Dimension Parameters, modifying the width or height values changes the model, but the model seems to be missing any labelled dimensions? I am obviously missing something? I would like to start creating parametric families including blends and this is causing some confusion. Any advice would be appreciated. Thanks.

[CoreyDaun · Accepted solution]

There are two methods by which an extrusion's size is controlled by "unseen forces", that is, without any readily apparent dimensions:

1. When one create an extrusion (or other solid), the profile is drawn with sketch lines (the magenta lines). If dimensions are placed upon these Sketch Lines while in the process of creating/editing this profile, then these dimensions will only be visible while the profile is being edited.

2. Typically, an extrusion's depth can be defined in the element's properties, with the parameters "Extrusion End" and "Extrusion Start". These parameters can be directly linked to a controlling parameter, so no actual dimensions are necessary.

In this example, the marble cube's size is controlled (with no apparent dimensions) by three parameters: Height, Length, and Width.

If you edit the extrusion (both Top and Bottom) for the  Air Terminal Family, you will see these dimensions appear.

[Anonymous]

and all becomes clear......thanks for your help.