To Pin or Unpin? that is the Revit Question

Following on from several recent posts about 'Pinning' elements in Revit, there are a few more subtleties to mention.  There are also some exceptions to the general rule of not being able to edit pinned elements.

Refer to these other posts on Revit Pins:

• The Revit Pin Icon
• Selecting Pinned Elements in Revit
• Revit Chain-Pins

Modifying Pinned Elements

A pinned element cannot be moved or rotated, but it can be copied

• If you try to move a selection that has any user-pinned elements, Revit will attempt to move them all (graphically showing the move) then warn you that they cannot be moved – so it puts them back and nothing happens.  This is a time-waster, so it is better to check for pin icons before moving large selections - and use the selection filter to check for hosted subcategories. 
• NB. It is not sensible to just click on the unpin icon on the ribbon before moving the selection - if you had any curtain walls or handrails, it would also unpin all the chain-pinned (type-driven hosted) curtain grids, panels, mullions and handrail supports - thus destroying the integrity of the model.

A pinned element cannot normally be deleted;

• If you try to delete a selection that has any pinned elements, Revit will behave quite differently to trying to move them:  If some elements in your selection are pinned, and some not, it will delete the unpinned elements and warn you about not deleting the pinned ones
• Revit will warn you about what is happening, but it is sensible to stop and think about what it has just done - and your next steps:  The undeleted elements are no longer selected, so it may be tricky to reselect the same ones?

Modifying Unpinned Elements

Once an element has been unpinned, you might think that it could be freely edited - but of course that is not true of 'Chain-Pinned' or type-driven hosted elements such as curtain panels, grids & panels.  there are some tricky rules and exceptions here:

Deleting Chain-Pinned Elements

• Unpinned type-driven Curtain Wall Mullions can be deleted;
• Unpinned type-driven Curtain Wall Grids cannot be deleted (but segments can be 'removed', laboriously, one by one);
• Unpinned type-driven Curtain Panels cannot be deleted - but you can change them to an 'Empty System Panel' (if you haven't purged the last type from your project, that is;  if you have purged it, you can't just create a new type of empty system panel, you have to copy one from elsewhere);
• Unpinned Railing Handrail supports can be deleted

Moving Chain-Pinned Elements

Chain-Pinned elements can only be moved within the constraints of their relationship to the parent element.  For example:

• Unpinned type-driven Curtain Wall Grids can be moved in one direction only;
• Unpinned type-driven Curtain Wall Mullions and Panels cannot be moved except by changing their properties, such as Offset;
• Unpinned Railing Handrail supports can be moved along the handrail - but there are some extreme weird behaviours when you try to do this.

Editing Chain-Pinned Elements

 The only Chain-Pinned elements that can be edited after unpinning are curtain panels – using the ‘Edit In-Place’ functionality.  In fact this allows you to do some crazy stuff with panels, which is quite surprising given all the other restrictions that prevent you from creating buildable elements!

Editing Pinned Elements

You would think that you cannot edit any pinned elements, but you would be wrong!

Floors (and other sketch based elements)

Pinned floors cannot be directly edited – the Edit icon is greyed out

Pinned floors can be modified (without editing the boundary) – by moving associated walls, depending on how the floor edges were defined:

• If the floor edge is defined by ‘Pick Wall’, the floor edge will move with the wall, even when the floor is pinned

• If the floor edge was done using ‘Pick Line’ or just drawing a line on/near the wall, when the wall is moved, the floor edge may still move with the wall, even if the sketch line was not locked to the wall.  The rules are not clear on this.

• This happens even if the floor sketch lines themselves are pinned when editing the floor. 

•  If a floor is moved, any pinned sketch boundary lines will just move with the whole floor - rendering the pin command inside a sketch pretty useless.

• Other pinned sketch-based components such as roofs, ceilings etc behave like floors.

This means that Wall Associations are stronger than pins in Revit.

Moves With Nearby Walls

An element that has been pinned, and has its property 'Moves With Nearby Elements' ticked will completely ignore the pin and move when a nearby wall moves

Wall associations win again!

Groups

Pinned Groups can be edited (without unpinning) - this is not the same behaviour as floor sketches.  However, it is not a bad thing in itself, as it means you can pin all groups all the time.

• Pinned elements inside a group will be moved or deleted when the parent group is moved or deleted, without so much as a 'By your leave'.

Properties

Instance & Type properties of pinned elements are generally editable - this means that such things as Base level or offset could be changed, thus rendering the 'Pin' less effective than you thought.

Modifying Pinned Datums

When a datum element (grid, level or reference plane) is pinned, you cannot change its 3D extents - not surprisingly.

• However, you can change its 2D extents in each view - which is a jolly good thing, because you can pin them, and leave them pinned!

Section Line

When a section line is pinned, you cannot change either its 3D or 2D extents.  In fact it does not display the extents or depth of view in plan when you select it.  This is an immensely frustrating and dangerous inconsistency in Revit.  It really ought to behave just like datums so that you could change its 2D extents, and at least see its depth of view - it is ironic that you can change the depth of view of a pinned section using the properties dialog box.

As soon as you unpin the section, you can adjust 2D, 3D extents and depth of view graphically in plan.  The big danger here is that you might forget to repin the section line, and some other fool may then move or delete your section line (along with all its carefully lined up 2D annotation).

For this reason it is wise to use the pin icon on the section line itself to unpin it - that way it retains the unpinned icon as a reminder to repin it immediately afterwards [If you use the ribbon unpin icon, it does not retain the unpinned icon on the section line itself]

Please go to the Revit Ideas forum and vote for 'Allow us to change 2D extents of pinned sections'

I am sure there are plenty of other examples of pinned elements in Revit that can be edited when you do not expect to be able to do so (or vice versa).

Selecting Pinned Elements in Revit

Following on from an earlier post about 'Chain-Pinned' elements in Revit, it is useful to point out the implications of different kinds of pinning when selecting elements.

Selecting Chain-Pinned Elements

Different hosted elements can be selected in different ways:

o        Tab-select to individually select chain-pinned elements.

o        Click-and-dragging across curtain walls or railings will also select individual hosted elements such as curtain grids, panels, mullions, top rails, handrails or supports  (regardless of whether they are chain-pinned or not).

You may find that you cannot select chain-pinned elements by either method.  This may be due to the ‘Selection Controls’

‘Select Pinned Elements’ can be turned on or off as desired;  it may be useful to disable selection so that chain-pinned elements cannot be selected when click-and-dragging across curtain walls (such as curtain grids or mullions)

 or

If ‘Select Pinned Elements’ is disabled, it applies to both pinned (parent elements) and chain-pinned (hosted elements) – thus, if a curtain wall is pinned, you would not be able to select the wall or the hosted mullions etc This is particularly noticeable when you click-and-drag across many curtain walls – you will see a forest of chain-pins

In this situation, it is well worth using the selection filter to select only the parent categories (eg. Walls)

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

Chain-Pin

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

Unpin

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.

Weird Stuff with Global Parameters in Revit

Following on from my earlier posts about transferring global parameters between Revit projects, and deleting global parameters, here is some quirky stuff that happens when you are working with Global parameters:

Weird Behaviour & Bugs

1.   Duplicate Labelled Dimensions

If you add a dimension to elements that already have a ‘global parameterised’ dimension, the new dimension automatically takes on the same parameter, without you realising.   If you subsequently delete that dimension, you get a message saying ‘A Dimension that is labeled . . .’  Unconstrain to remove constraint

• If you expand the warning, it tells you what the Parameter label is

•  It does not tell you that you are deleting a secondary (redundant) dimension with the same label as another dimension, which still remains in the model

 2.  GP Equals Constraint Conflict – Fixed in v2018 (?)

If a dimension between two elements (say gridlines) has a GP associated to it, then you place a dimension between the grids and an element midway between them, you would expect to be able to change that dimension to ‘Equals’. Illogically, Revit does not allow this – it warns you that it needs to remove the constraint. Unfortunately if you go ahead, it removes the GP constraint but keeps the Equals constraint – which is not very helpful as you now need to guess which other constraint it removed. It does not highlight the other constraint

• I recommend that you cancel, then figure out where the conflict is - do not click on 'Remove Label'
• One solution to this is to create another GP that is a fraction of the original one (half, in this example), and apply that to the secondary dimension, instead of an equals constraint

• Another solution is to put the equality constraints between other elements that are in the same location but not GP dimensioned – eg between two walls that are aligned to the gridlines.
• NB. This problem does not occur if the GP associated dimension is a reporting parameter.
• This bug is reportedly fixed in v2018, but I have not had time to test it yet

3.  Edit Witness Line Bug

If you associate a GP to a dimension, and then subsequently delete the dimension, Revit will ask you if you want to unconstrain (remove the constraint) – this is good behaviour. However, if you edit a witness line instead of deleting the dimension, Revit removes the GP association (as you would expect), but does not ask if you want to remove the constraint – effectively hiding the constraint. This is really bad behaviour by Revit, because it means you can end up with lots of hidden constraints, which catch you out later on. Autodesk refuse to accept that this is an inconsistency in the software that should be changed. I recommend that you never edit a witness line on a GP associated dimension.

4.  Shape-Handles vs Calculation

If you have a family that has grip handles when placed in the model, those handles can be ‘hidden’ when GPs are associated with certain properties in the family. This happens if the property is used in a formula that drives the geometry related to the shape-handle:

• No GPs associated – shape-handles available

 

• GP associated to a property used in width formula

• In this situation, it is better not to associate the GP directly to the property. Instead you need to use a dimension with a reporting GP associated to it. Then the association is far enough removed so the shape-handles are unaffected.

5.  Circular Chain of References

• At some point you are likely to encounter this warning dialog:

 

• I strongly recommend that you do not click on ‘Resolve’ because it will remove a formula, but not necessarily the one you are expecting, nor the one you just added that caused the problem. Instead you should cancel and figure out what is causing the problem – first click on ‘Expand’ to see if you can figure out the conflict; although using the ‘Delete Checked’ option does not seem to resolve anything (the same dialog just as likely pops up again), so you will then have to cancel anyway.

6.  Change Instance to Type

If parameters are changed from instance to type in a family, then reloaded into a project, you may get this message if the parameters had been associated to GPs

• You then have to reassociate the property to the GP – but it is easier to do as it is likely to be only one type property to relink

7. Duplicate Type Loses Associations

If you duplicate a family type that has GP associations to any type properties they lose the associations.