Thursday, 8 February 2018

Revit Chain-Pins

Revit has two entirely different ways of pinning elements, but they share the same UI commands & icons, so this is a recipe for confusion.  I will try to shed some light on the differences here:

Most elements in Revit can be manually pinned by a user.  This will lock an element in place to prevent it being moved, rotated or deleted.
 Pinned elements can be unpinned  to free them up to be moved, rotated or deleted


Some Revit elements host other elements that can be locked / unlocked in place on the host – this also uses a ‘Pin’ icon with a chain-link symbol beside it.  The difference in icon to a normal pin is very subtle, and easily missed - but is really important to see and understand.
I like to call these ‘Chain-Pinned’ elements, because of the chain-link symbol - and we need some kind of phrase to differentiate them from regular pinning.  They could also be described as host ‘Type-Driven’ because some of their parameters are controlled by the Type Properties of the parent.

Examples of Chain-Pinned elements are:

Element / Category types
o        Curtain Wall Grids (only if spacing is set in curtain wall type)
o        Curtain Wall Mullions (only if mullion type is set in curtain wall type)
o        Curtain Wall Panels (only if panel type is set in curtain wall type)
o        Handrail Supports


When a ‘Chain-Pinned’ element is selected it can be unpinned by clicking on the element pin or the unpin symbol on the ribbon.  This can be confusing because the pin symbol on the element displays its current status (pinned, with chain-link);  while the icon on the ribbon is an action, showing what you can and might want to do to it (but no chain-link, because the command doubles up for both kinds of pin):

o        The element symbol will change to unpinned status, with the chain-link cleverly hidden behind the red cross - you have to look carefully!

o        It makes no difference to the behaviour which pin icon is clicked on – element or ribbon (unlike regular user pins);  the unpinned icon always shows up when the element is selected.

Chain-Pinned Element Behaviour

When a Chain-Pinned element is selected (but has not been unpinned): 

o        Some of its properties may be locked (eg. Hand Clearance on Handrail Supports)
o        Its type is locked
o        It cannot be moved or otherwise manipulated
o        It cannot be deleted

When a Chain-Pinned element is unpinned:
o        Some locked instance properties are available to be changed (eg. Hand Clearance on Handrail Supports)
o        Its type is available to be changed to others of the same category
o        It can be moved (Curtain Wall Grids & Handrail Supports)
o        It can be deleted (Curtain Wall Mullions & Handrail Supports)

An unpinned Chain-Pinned element can be re-pinned:
o        Its properties will revert to those dictated by the parent (eg. Hand clearance on Handrail Supports)
o        Its type will revert to that set in the parent family type.
o        It will be moved back to its original position
o        Deleted unpinned hosted elements cannot be directly replaced to their original position.  This has to be achieved by alternative methods: 
  • Mullions can be added to curtain grids; 
  •  Handrail Supports can be reinstated by copying another one or by resetting the whole handrail (Be very careful with this - all other modifications will be lost too!)

Editing Chain-Pinned Elements

The only Chain-Pinned elements that can be edited after unpinning are curtain panels – using the ‘Edit In-Place’ functionality, which allows you to change the outline of the curtain panel using sketch tools.

I hope this sheds some light on a confusing Revit topic.  Go forth and unchain those pinned hosted elements.  Or don't, as the case may be - sometimes it is important for them to remain chain-pinned so that global changes can be quickly made.  Once unpinned, you lose that capability.

1 comment:

  1. pretty thorough explanation.

    Going sideways, I would mention the Golden pin at the bottom right corner of the window, being able to select / or not select a pinned element

    many ways to lock, indeed:

    the pin,
    the chain-pinned,
    the padlock,
    the paper clip (for project base point and topography point)
    pad-locked dimensions,
    labeled dimensions or parameters in families or with global parameters in the project, locked with a "value" in the formula

    and I am probably missing a couple...