Link Global Parameters to Built-in Revit Properties

During my research on Global Parameters in Revit, I have compiled a list of built-in (system) properties that you can directly associated to Global Parameters.  For each category, there are certain parameters that have the little 'link' button to the right of the property value - this is used for linking.  If there is no button, then it cannot be directly linked.

This list is not something that we have any control over - each parameter has to be 'enabled' by the software developers.  Below is a list of built-in parameters that I have found, which can be directly associated to Global Parameters (in v2016 R2 & v2017 in red). This list only shows the categories that appear when the discipline is set to Architecture;  there may be other structural and MEP parameters that are also available (but not listed here);  there may also be other parameters that only show up when you change certain settings - so I might not have discovered them:

Category                             Parameter

o   Areas                   -

o   Area boundary    -

o   Casework            -

o   Ceilings                            Height Offset From Level

o   Columns                           Base Offset (v2017)
                                             Top Offset  (v2017)

o   Curtain Wall Grid            -

o   Curtain Panel                   -

o   Curtain System                -

o   Curtain Wall Mullion       -

o   Door                                 Sill Height    (v2017)
                                             Head Height   (v2017)
                                             Height   (v2017 instance or type parameter)
                                             Rough Height  (v2017 instance or type parameter)
                                             Width   (v2017 instance or type parameter)
                                             Rough Width  (v2017 instance or type parameter)
                                             Thickness  (v2017)

o   Electrical Fixtures  -

o   Floor -

o   Floor Slab Edge    -

o   Furniture     -

o   Generic      -

o   Level                                 Computational Height

o   Lighting Fixture      -

o   Line  -

o   Mass -

o   Mechanical Equipment -

o   Parking       -

o   Planting      -

o   Plumbing    -

o   Railings        -

o   Railings: Supports -

o   Railings: Handrails -

o   Railings: Top Rails -

o   Ramp                                 Width

o   Roofs           -

o   Roof Soffits                      Height Offset From Level

o   Roof Fascia           -

o   Roof Gutter           -

o   Room          -

o   Room Separation  -

o   Shaft Opening      -

o   Site   -

o   Site: Property Line -

o   Specialty Equipment  -

o   Stairs                                 Actual Tread Depth

o   Stair Run                           Extend Below Riser Base      (only on lowest run)

o   Stair Landing         -

o   Stair: Support         -

o   Struct. Column                Base Offset (v2017)
                                               Top Offset  (v2017)

o   Struct. Framing              Start Join Cutback
                                               End Join Cutback
                                             y Offset Value
                                             z Offset Value

o   Structural Truss      -

o   Str. Beam System            Elevation
                                               Fixed Spacing / Maximum Spacing / Clear Spacing

o   Struct.Foundations             

o   Toposurface          -

o   Wall                                   Base Offset  (v2017)
                                               Top Offset  (v2017)

o   Wall Reveal                      Offset From Wall
                                              Offset From Level

o   Wall Sweep                       Offset From Wall
                                              Offset From Level

o   Window                            Sill Height  (v2017)
                                              Head Height  (v2017)
                                              Height  (v2017 instance or type parameter)
                                              Rough Height  (v2017 instance & type parameter)
                                              Width  (v2017 instance or type parameter)
                                              Rough Width  (v2017 instance or type parameter)

There is one parameter missing from this list that would be invaluable to be able to associate:

      Floors                            Height Offset From Level

If you would like this one to be enabled, please put in a change request to Autodesk (the more requests, the more likely it is to be done).  Alternatively you could use the latest method of voicing your opinions or wishlists - currently the Autodesk Revit Ideas forum  .  I have posted a wishlist idea here - please vote for it

Global Parameters in Revit 2017

Global Parameters were introduced in Revit v2016 R2, and then improved in v2017.  The whole concept of parameters in Revit can be very confusing because there are so many different kinds of them - and they inter-relate in a complex matrix or rules and exceptions (welcome to Revit!).  I have done a detailed analysis of all those exceptions in order to understand the limitations.

Global Parameters: 

The Revit Help File states:  

"Global parameters bring the power of parametric families into the project environment.  You can create global parameters that are specific to a single project file but that are not assigned to categories. Use global parameters to drive the value of a dimension or a constraint, associate to an element instance property to drive its value, or report the value of a dimension, so the value can be used in the equations of other global parameters."

Global Parameters (GPs) can be applied in a similar way to the Family Editor:  

• Apply to a dimension by selecting the dimension and changing its label (on the options toolbar in v2016R2 or the ribbon in v2017);  the label is not available for multi-segment dimensions in v2016R2, but can be applied to multi-segment dimensions in v2017 (NB. be very careful doing that as your whole model can move).

• Once applied, the dimension has a small pencil symbol beside it.
• This means that two (or more) non-adjacent dimensions can have the same parameter applied to them

• Apply to the instance properties of an element by clicking on the tiny button that may appear to the right of a given property in the Instance Properties Palette
• Once applied, the button shows a tiny equals sign on it

• A Global parameter (GP) can be used in formulas for other parameters;  

• If a GP is deleted, then any formulas using that GP would also be cleared - luckily it gives a warning.  

 

• If a GP is deleted, where it has been assigned to elements, it also gives a warning with a number of elements to be affected - if you proceed all those associations would be lost.  In the family editor deleting a parameter would affect only that family, but with Global Parameters it would affect the whole project.  So, be careful.

Limitations

This promises to be a very powerful new feature, but it has many limitations at this stage:

• They can only be assigned to a very few system parameters on certain system family categories (eg. To beams but not to floors) – and most likely not the ones you want.
• For external families global parameters can only be assigned to user defined instance properties in v2016R2 (not type properties or system properties).  In v2017 GPs can be applied to type properties and a few system instance properties too.
• You cannot assign them to array numbers

The Global Parameters dialog is accessed from the Manage tab. 

In v2016R2 it has one long list of parameters, with no way to organise or group within the list apart from sorting alphabetically – so a naming convention will be vital, otherwise related parameters will be jumbled; 

There is a so-called search capability, but it is fairly crude - it is actually a filter, not a search (see more on this later). 

 

• You can add tooltips to Global Parameters but in v2016R2 they only show up in the dialog box, which is of limited usefulness.  In v2017, they show in-canvas in the model when you select a dimension, which is much better.  They do not show in the model when assigned directly to an element property.   Tooltips should always be used as a record of what each and every parameter is for - as you may not remember what it is for 2 weeks later (or 2 days in my case). 

v2017 has much better organisational methods, along the same lines as the family editor:

• It allows you to group parameters.

• You can sort parameters alphabetically

•  You can move parameters up or down the list

 

What Else is New for Global Parameters in v2017

Improvements listed in the v2017 help files include:

• Type Parameters can now be linked to Global Parameters (GPs) - this gives us more power to make global changes, but it is less significant than instance parameters because type parameters in themselves allow limited global changes
• Assign global parameters to groups within the list in the GP dialog box (NB. don't misread this as I first did, and imagine that you can assign GPs to model groups in the project - it is only in the dialog box as described above)
• Reorder GPs in the list (as described above)
• Filter a schedule by parameters that have GP associations - this should be invaluable for tracking down all those associations that are making unexpected changes to your model!

• Show Label in View - hopefully useful, but that 'There is no open view. . .' message is a worry on large projects, where it often cannot find a view (for warnings), so I don't know how useful it will actually be?

• Transfer GPs between projects (Transfer Project Standards) - yes, that is great but it is all or nothing, as per usual for this feature.  So it is like applying a sledgehammer - you could transfer two hundred parameters when you only want two.   NB. If there are any materials selected for any material type global parameters, the materials will be transferred too.

• Project Parameters

  Whatever you do, don't tell anyone about this, but hidden away in v2017 help files it states that they have enabled us to assign Global Parameters to Project Parameters - for both system families and external families.. So what! you might think?
  
  In fact this is huge - what it means is that you can create a project parameter (of any kind) seemingly for any category, and then a little 'parameter link' button will appear to the right of its properties when the relevant element(s) is(are) selected, and you can assign a global parameter. That means we can add them to walls, floors, etc. And of course we can make the project parameters Shared so we can properly schedule and tag them. This is a big deal because you cannot tag the actual global parameters. Hmm, there must be some catch I haven't thought of yet.
  
  Thank you Autodesk - I am jumping for joy about this, even if you neglected to do your own flag waving! 

• Secret Enhancements :

1. They have enabled a few more system instance parameters so we can assign global parameters for categories that actually might be useful to both architects and structural engineers:
   Top and Base offsets for walls, columns and structural columns.  Wow!  I will be able to change the height of a whole bunch of pre-selected walls at the click of a mouse when a floor slab changes thickness (without having to use that 'attach' command that causes so much trouble).
   Sadly they are still ignoring Floor 'Offset from Level' which would be very useful to be able to assign GPs to.

Responsibility

With great power comes great responsibility.  If this feature is not well managed or controlled, it could make your models impossible to work with as they could end up with many hidden constraints and relationships. Changing parameter values can have dramatic effects on your model – like moving gridlines, so pinning and locking will be important.  How do you manage this?  Autodesk have given us some tools for this:

• The 'Reveal Constraints' tool will show dimensions that have had global parameters assigned to them; It shows an additional red dimension with a label, below/beside the original dimension.  NB. If the original labelled dimension has been deleted but the constraint retained, it will still show the red dimension under Reveal Constraints, which is a very good thing.

•  Reveal Constraints will not display global parameters assigned directly to instance properties - the only indication of that is the tiny equals symbol in the instance properties dialog box.  NB. even that may not show when the selected element is part of a model group - a bug I suspect.

• There is a ‘Show…’ button that will highlight elements or dimensions that have been constrained by GPs; once displayed on screen, you cannot navigate in a view with the GP dialog open. This does also work for elements that have GPs directly assigned to a property (unlike the Reveal Constraints tool)

• The aforementioned ability (in v2017) to filter a schedule by parameters that have GP associations will be an invaluable tool in your kit.
• GPs can be applied to multi-segment dimensions in v2017 - this means that if you selected a dimension string that has various different values, as soon as you apply a GP to it, all the dimension segments would become the same.  This is very powerful, but also extremely dangerous - be very careful doing that as your whole model can move if the dimensions happened to be across a bunch of gridlines for example. 
  Quite frankly, I wish that they had not enabled this in v2017 - I predict more tears before bedtime!

Power To The People

If you want to know more about how Global Parameters can be used on real (and imaginary) projects please join me at RTC NA in Scottsdale, Arizona on 14 July 2016 for my presentation "Power to the People" Session 1.4 at 3.15pm.  I will be giving live demonstrations in Revit of a number of different possible applications for Global Parameters.

What's New in Revit 2017

As Steve Stafford has compiled a comprehensive list of new Revit 2017 features over on OpEd, I will not write a list here.  Instead I will comment on a few features - especially since the Autodesk Help files are so sparse on detail.  We all need to know the benefits and shortcomings of each new feature.

I have previously commented on v2016 R2 features (in this link), which are obviously now included in v2017.

New in Revit 2017 (selected features)

Global Parameters

My initial description of Global Parameters as introduced in v2016 R2  is only relevant if you are still using v2016R2.
For more details on Global Parameters in v2017 click here

Improvements in v2017 are more significant than I first thought - they include:

• Type Parameters can now be linked to Global Parameters (GPs)
• Assign global parameters to groups within the list in the GP dialog box
• Reorder GPs in the list
• Filter a schedule by parameters that have GP associations - this should be invaluable for tracking down all those associations that are making unexpected changes to your model!
• Show Label in View - hopefully useful, but that 'Cannot find view. . .' message is a worry when looking for other warnings and issues, so I don't know how useful it will actually be?
• Transfer GPs between projects

All of these are very welcome additions to this exciting new feature.  However, we are still missing the ability to associate GPs directly to many system properties, although this has improved in v2017.

More on this . . . . Global Parameters in v2017 click here

Schedule Templates

Schedule templates now include parameters for Fields, Filters, Sorting/Grouping and formatting - previously it was only the Appearance that could be included in a schedule template.  This sounds wonderful, but in my opinion it is very dangerous in the way it has been implemented:
If you apply a schedule template to an existing schedule, it will entirely replace all your fields, filters, sorting, formatting.  This means that if you had all sorts of complex calculation fields in the original schedule, they will be destroyed and lost forever!  It is all or nothing - you cannot just include some things in the template without the others (eg. filters & formatting only, without fields).  I understand that it would be tricky to separate out what is contained in each template as the fields are interrelated - ie. it has to exist in the field list in order to be formatted or used in a filter.  However, I think we should have had a cleverer implementation that allowed us more flexibility and safer control.
Unless the final rollout of v2017 has changed since I last tested, there is no ability to "overwrite or append" to a schedule where fields already exist - it just replaces without so much as a 'by your leave'.  Mark my words:  There will be tears before bedtime!

So, a word of caution:  plan how you use this very, very carefully - set up some complex scheduling and save it as a template first so you don't lose the calculations!

Combine Schedule Fields

Steve Stafford described this very well in his blog over on OpEd, so I won't replicate the description.  While this is a great step in the right direction, it will only allow you to combine or 'concatenate' parameters in the actual schedule output.  This means that combined parameters are not visible in the element properties dialog, nor can you tag them, nor will they be exported (unless you export just the schedule).  So if you need to actually populate element properties with combined parameters, you will still need to use Dynamo, API or a third party add-in.

Calculations in Annotation Tags

Another very welcome addition to tagging capabilities, but again this comes with some serious limitations:   The calculations are defined in the tag in family editor - this means that you have to replicate identical calculations in a schedule if you want to see the same results in both schedules and tags.  That is asking for user errors.  In addition, when working in the tag, you will not be able to access any Project Parameters, Schedule Parameters, and some System Parameters only visible in projects (such as offset from Level) - depending on the category, some system parameters are available in tags, some are not.  eg. Base Offset for wall is not available; but Sill Height is available for windows.  This means that we will need to use more Shared Parameters instead of non-shared Project Parameters, although that won't solve the issue of System parameters - of course shared parameters can't be used in all situations anyway.

This is a good first step to fixing a problem with tags, but it needs to go much further by allowing us to embed the calculations back into the actual elements so they only need to be done once then be available everywhere (properties, schedule, tag, export).

Tangency Locks

[Edit] When editing a sketch in the family editor, we can now 'lock' the join between a line and an arc to maintain it as a tangent join.  I am very happy about this new feature - I have long struggled to control arcs in Revit.  Most of the time, in simple situations it works well.

In this example, the end of one line is adjusted so the line changes angle - and the arc is extended to maintain the tangency.

However, it needs to be used with a little caution until we all understand exactly how it works and what it does to overall sketches.  I tested the simple sketch above a little more by adding parameters to the radii, and it had some unexpected consequences.  Previously, if you moved/rotated a line that had a tangent arc at its end, it often just broke the tangency.  Now it can possibly have a knock-on effect all along the sketch:  It can completely move lines on the sketch way along the chain beyond the tancency lock.

 When the end of the right hand line is moved in, the radii change, and the left hand line moves in

When the end of the right hand line is moved out, the radii increase, and the left hand line moves left

Move the end of the line a bit further and the sketch goes crazy:

As the tangencies cannot be broken, something else has to give!  To prevent this sort of behaviour, every line would have to be dimensioned/constrained in location and angle.

This means that we will need to put more thought into controlling the whole sketch - not necessarily a bad thing, but it could cause problems if you add tangency locks to old sketches.  We have often been lazy in the past because we could get away without adding dimensions or constraints to many lines in a sketch - Revit would do the work for us with implied constraints (lines generally stayed parallel even if the moved, and they locked themselves to nearby reference planes).

More on this - click here, as it requires a careful analysis . . . .

Elevation Depth Cueing

I have done some testing of this new feature - read about Depth Cueing here for more detail.  Read about depth cueing on angled/curved walls here.
It seems that in order to display receding distance in Elevation and Section views in Revit, Autodesk have chosen the easy path of making lines lighter the further they are away, rather than allowing control of line weights, which is the old conventional drafting method.  It certainly does achieve an effect of 'distance' even if it has some limitations (like not working with line weights or anything worked over using the Linework tool).  You may not like the method it uses or the simple controls which are easy to use but will probably make consistent output very hard to achieve.  You may also not like printing all your elevations using the raster driver, although I hear that it is less of an issue than it used to be.

Installing Revit 2017

Installing Revit 2017 using a download is a whole new adventure (not a pleasant one)
Read about download/installation here - not much fun at all
Read about installing from DVD media here - a much pleasanter experience

New Revit Icon

I like the new Revit icon - it looks less like folded paper, and more like a carved sculpture that you could not possibly make using the massing tool, however hard you try.  I like to have a different icon each release so that you can easily tell which version is showing up in your windows taskbar - especially if you have multiple versions open.

Conclusion

This post is not meant to sound negative - I am just warning you about issues with new features that sound too good to be true!  They all have value but need to be treated with care.

Is Revit 2017 good value for all that subscription money you payout?  You might not think so, but I could not possibly comment.  For an architect there is not a huge amount to be excited about - many new features are relevant to other disciplines or might be of more benefit to others downstream.

There are no big standout features in v2017 that we must have now, so I will be a little cautious about rushing into the upgrade, particularly as there are a lot of goodies to be had in v2016 R2 already, without the pain of another file format change.  When you add the list of v2017 features to those in v2016 R2, it is a reasonable number of small additions and tweaks - but there are so many, many more to address, let alone some of the underlying structural changes that need to happen in order for us to be able to use Revit efficiently.