Filtering Filters in Revit

The term "Filter" is much used in Revit - and it means different things in different situations.  Filters also follow varied and confusing rules depending on what you are doing.  Below are some of the rules and exceptions:

Coffee Filters

The 'Filter' icon in Revit probably makes good sense to most Americans, but others around the world might be a bit puzzled - it is a historical image, much like the Floppy Disk for 'Save'.

In the USA, coffee filters are still quite common:

Many American restaurants have a coffee filter machine, with a pot of brown liquid sitting on a hot-plate for hours after it has been dripped through a paper filter.

 

In Europe you might find various different machines for making coffee - plungers (French Press) used to be quite popular:

In Greece or Turkey, traditional coffee was made in copper pots.  now of course, there are updated electric versions available.

In Australia coffee-plungers are now a rarity, while filters can only be found in antique and junk shops.  Nothing less than a full-on espresso machine will do in even the smallest cafe.  A restaurant with a coffee filter would be laughed out of town:

There ends the 'Filter' icon history lesson.  I have to say that I do like the coffee filter as an icon because it is neat and distinctive - but it might puzzle the younger generation.  I can't see an espresso machine making a good icon.

Jeff has pointed out that the filter icon is probably derived from laboratory funnel filters - probably true, and much more logical than my coffee filter theory!

Selection Filters

When you select a number of elements in Revit, two Selection Filters icons are activated:

Status Bar Filter Icon

The Status Bar icon (lower right of screen) shows the number of selected elements; and the coffee filter icon, which gives you access to the Selection Filter dialog box.

 

Ribbon Selection Filter Commands

Ribbon Selection Filter commands allow you to:

• Save, Load or Edit element selections
• access to the Selection Filter dialog box

 

This is an invaluable (but underused) tool for filtering down your selection

It is really important to check the selection filter to make sure that you have not accidentally selected partially hidden items (eg. floors, section lines) before you delete, modify or copy them.

View Filters

View filters are created and saved in each project, and can be applied to:

• individual views
• multiple views or
• view templates

View filter rules allow AND and/or OR

• OR filter capability was added to Revit in v2019, which made our lives so much easier
  
• OR filter rules are pure gold (as the French would say)
  

View filters can be used to:

• Hide/show elements (Visibility) or 
• To override their appearance

 Filter Overrides are not part of the View Filter:

• Overrides are part of the view definition - meaning they are tricky to maintain or duplicate
• Overrides can be part of a View Template
  

• One of the annoying restrictions in View Filters is that Shared Parameters created in loadable Families are not available for use in View filters - unless you also add them as Project Parameters - refer to this blog post
  

More on View Filters in another blog post . . . .

Schedule Filters

Schedule Filters are quite different to View Filters in many ways:

• Schedule Filters are an integral part of each schedule - they cannot be separately applied to other similar schedules - this is entirely different and inconsistent to View filters
• However, Schedule Filters can now be included in View Templates that are then applied to multiple schedules (since v2017).
• Be warned that if you create a complex filter as part of a schedule, then apply a view template, your filter could be overridden by whatever is in the template - never to be retrieved.
  

• There is a huge list of system parameters that are not available for use in Schedule Filters - way too many to list here.  Autodesk are slowly adding new ones with each release, but it is a very slow feed, rather like an old-fashioned coffee filter that is clogged up with coffee grounds.
  

• Shared Parameters created in loadable Families are available for use in Schedule filters - this is a good thing (but not consistent with View Filters).

• Schedule Filters do not allow an 'OR' rule - this is a really bad thing (and not consistent with View Filters);  they only allow 'AND' rules.
  

• Schedule Filters have a fixed number of 'AND' rules - currently 7 (this was increased to 7 a few years back).

 

More on Schedule Filters in another blog post . . . .

Browser Filters

Project Browser has its own filtering system:

• It is limited to 3 'AND' rules, which includes some System Parameters and Shared Parameters
  

• A few years back Autodesk added "Family" and "Type" as separate parameters for filtering, which is much better

• Unfortunately the default filter "all" is by the combined "Family and Type" parameter, which cannot be edited - I would prefer the "all" filter to be by "Family" and "Type" as two separate rules.
  

Parameter Search Filters

A few years back (v2017) Autodesk added a new filtering function to a couple of dialog boxes.  They referred to them as "Search" capabilities but really they are just filters - which adds to the confusion.

Global Parameters Dialog Box

There is a 'Search parameters' box at the top of the dialog.

If you type in a word or part of a word, it does not search for parameters containing that (part)word.  What it does is to filter the parameters in the dialog so that it only displays those containing the (part)word in any of the columns (parameter, value or formula);

• Any parameters not matching the filter are hidden
  

I seldom use this capability - partly because the way it was implemented is quite confusing.  No doubt there are people out there who love it!

It can catch the unsuspecting user out - if you don't realise that the focus is in that Search box, and you type something in (say a value that you are trying to input in a parameter), then all your parameters may disappear.  This could be very disconcerting.

I think it would have been easier to understand if the Parameter grouping titles did not get hidden.

Family Types Dialog Box

The same capability is also available in the Family Types dialog in the Family editor (since v2017).

The same gotcha/confusion is also available in the Family Types dialog in the Family editor.

 

 

Shared Parameters in Revit View Filters

Here is another Revit Gotcha for young and old: 

Family Editor Shared Parameters

If you add a new Shared Parameter in the family editor, you might expect that parameter to be available in a project in all situations.  You would be wrong!

Shared Parameters created in the family editor, and then loaded into a project have two entirely different (inconsistent) behaviours:

• In Schedules, the shared parameters will automatically be available to add as fields

• In View Filters, the family shared parameters will not be available to add as fields

This is quite confusing and inconsistent.  It can also catch you out, however experienced with Revit you might be - as I recently discovered when demonstrating how to create View Filters to a client

Schedules

If you create a new schedule  for the category of the recently loaded family, the Shared Parameter is automatically available in the list of available fields - as you might expect:  it is one of their mystical powers.

View Filters

Try the same trick with View Filters and you will probably get a nasty surprise

 

 Workaround

To make the shared parameters available for use in View Filters, you have to add them (again) as Project Parameters.

 

  

 

View Filter

If you go back to the View Filter definition, you will see that the Shared Parameter is now available as a field to be added.

As a BIM Manager, I would once have known about this Revit inconsistency - but I just plain forgot!  There is no way we can remember all of the inconsistencies.  And why should we have to?

Fortunately, Autodesk are slowly addressing some of these irritations - but it is such a laborious process.

Stair Section Detail Level in Revit

Here is yet another problem with Revit Stairs that really needs to be fixed by Autodesk:  

The view 'Detail Level' display in section is not consistent between walls, floors and stairs (not to mention ramps!):

View Detail Level

When a view is set to Medium or Fine detail level, sections of most categories display the correct materials:

When the View detail level is set to 'Coarse', the cut hatching display of some elements is overridden by the Type properties 'Coarse Scale Fill Pattern'

This capability is available only for certain categories - meaning that the display of stairs is pretty hopeless at Coarse scale

 

Workarounds

What to do about this?  There are several possible ways to resolve this lack in Revit, but none is very good!

Visibility Graphics

You can over-ride the cut pattern of stairs - but this requires several steps (excuse the pun) on top of just changing one View Detail Level setting:

Due to the fiddly nature of changing this in the view (similar settings may need to be applied to other categories), you would certainly need to include this as part of a View Template - so it could be applied or removed at the flick of a switch.

Filters

You could also try using a View Filter, as it could potentially be applied to multiple categories

This has an advantage in that it is more "discoverable" than searching through all the category overrides - unless you have a gazillion filters applied!

Another advantage in Revit 2021 is the ability to "Enable" or "Disable" the filter without losing the override settings - a very useful new enhancement for Filters.

Downsides

The View Detail Level is very easy to switch on/off - and it affects all categories that have the built-in Coarse Scale override capability.  If you set the view back to Medium, the 'by category' cut pattern overrides get left behind - so you would need another operation to remove those (hence the need to use View Templates).

Another problem with the Visibility Graphics workarounds is what happens when you choose anything other than black solid fill as your hatching override:

If you make it grey . . .

 

The Stairs will show the joint lines between different materials - you may or may not want this, but it is clearly different behaviour to the Coarse Detail Level control that hides the material join lines and treats it as one material, for a nice clean look.

Of course, this is not helped by the inability to join walls/floors to Stairs !!  You still get the joint lines between those.  Refer to Stair Joint Lines

The Worst Workaround

Filled Regions are extremely useful for patching up Revit's inadequacies, but they are not popular with BIM & Model Managers because they cause so many other problems as soon as a model changes.

Filled Regions allow you to make the hatching look exactly how you want, because they allow some of their edges to be "Invisible Lines" - thus they can appear to join with adjacent "real' cut hatching.

Filled regions are placed per view, so if you have multiple sections cutting through the same or similar parts of the model you may end up with many filled regions.

One possible method to manage that problem is to include them in 'Detail Groups' - but they are also problematic to manage, not to mention a major shortcoming of really slowing down your Revit model if you have too many of them.

Conclusion

Whichever workaround you use the most important thing to do is to follow company standard procedures - and be consistent.  Agree with your workmates on which dodgy workaround to use, and stick to it.  This will make it so much easier to come back to make changes when the model is updated.

Path of Travel - The Dalek of Revit 2020

Path of Travel - New Feature in Revit 2020

One of the new features that is particularly relevant for architects is the 'Route Analysis' tool.  This works by placing point-to-point lines between the start and finish of a route in plan.  Revit will then analyse this and find the shortest route between the points, avoiding obstacles on the way, and it will place a segmented detail line along that path, in the chosen view.  The intention for this tool is to create such things as:

• Fire Escape plans
• Emergency Evacuation plans
• Life Safety plans (USA)

Here follows a detailed analysis of the new feature:

Analysis of Route Analysis

The tool is found on the Analyse tab, called 'Path of Travel'

Once the tool is activated, the ribbon displays a Linestyle choice.  It defaults to a linestyle called 'Path of Travel Lines'

Step one is to draw a line between two points.

 Revit then thinks a moment and places a 'Detail Line' segmented pathway between the two points

The first thing you'll notice is that its really hard to see.

This is because the default linestyle is not set to what you'll most likely need.

Path Linestyle

The default linestyle is system defined, but unfortunately its name is not enclosed in < > brackets, so its likely to get lost in amongst many linestyles.

Go to the Linestyles dialog to change its global settings (Not to 'Object Styles', which might be your first instinct) - it  is after all, just a detail line.

• Note that it cannot be deleted or renamed. 
• You can change its Weight, Colour or Pattern
• In this case I've just bumped up the weight to something really visible

You can also create some more linestyles to use for different kinds of paths - this is the nearest we'll get to creating 'Types'.

In this example you might want to distinguish between an escape path to Outside vs to a Stair:

• The original line can be changed to 'Path to Outside'
•  A new line 'Path to Stair' could be added

 

• Revit will again calculate the shortest path (around furniture/fixtures)

 Notice how hard it is to read the direction of the lines. 

• Sadly there does not appear to be anything the user can do about the dot at the start, or the arrowhead - neither of which are very distinguishable with heavy lineweights at any scale above 1:50 (is that 1" to 48' in imperial?).
• Overlapping lines can be moved Backwards/Forwards

Update Paths

If the underlying geometry is changed, you may want to update the path

• Select a path
• Click on 'Update Path' on the ribbon
• Revit will recalculate it

Move It 

I am quite sure this was not the design intent of the update command, but it serves to demonstrate some weird behaviour:

• Select a path
• Move it
• In this example I moved it partially out of the building (keeping the ends inside)

 

• Try the 'Update' command
• It may or may not work

• This may be your first experience of a very unhelpful warning that does not tell you why it cannot update the path
• My instinct told me to try again, with the whole path kept inside the building

•  This time it worked

• A gold star to anyone who noticed that the path did not avoid all of the furniture - even on the very first attempt

Split Levels & Dizzying Heights

You may have noticed that this example is the Autodesk sample file - a perfect vehicle for testing, as it has a split-level plan:

• The living area is 3 lower than the rest of the house - and this is where Revit has failed to pick up the obstacles.
• The question is, does the furniture project high enough to interrupt the path?
• A section shows that it should - just.

Just to be certain, we should check the calculation heights:

• Click on the tiny, tiny Route Analysis settings arrow

•  The lower height is set to a default value of 203.2mm (8") above the view associated level (upper part of split level)

• This may be just above the furniture, so I tried dropping it to zero, then 'Update' the path
• Computer says 'No'

• Then I tried just above floor level, say 10mm, but it still failed
• The lowest level it would let me go without failing, was 175mm, but it still did not pick up the furniture on the lower floor.

 I then set the lower height back to 10mm, and tried a new path:

• This time the message was a bit more informative:

I still don't know what the problem is, but it is a bit of a worry that the Autodesk sample file has uncovered a problem or limitation in the software so easily.  I'll update this section when more information comes to light, from Autodesk.

[Edit - it seems that the only part of the sofa high enough to be in the analysis zone is the sofa back, which explains the initial problem - but does not explain why the update path does not work when you lower the analysis zone - Refer to this blog post for more detail]

The Dalek of Revit 2020

Whovians would already have guessed that these paths of travel cannot go upstairs (or down).  That is certainly going to be a limitation for some situations, not the least being split-level plans.

Properties

Each Path that you place has some interesting system instance properties

• Strangely there is no 'Comments' property.  This is very unusual, as almost every other element type does have a system Comments property that can be used in almost any situation (Filter, tag, schedule, key schedule etc)
• The only properties that a user can change are the Line Style and Mark
• Time = Calculated time it takes to walk from the start point to the end point of the path of travel. Walking speed is set to 3 mph/1.34 mps (Read only)  [From help file - mps presumably means metres/second.  I'd prefer 5 kilometres /hour]
• Length = Total length of all segments of a path (Read only)

• The system properties can tagged

•  And scheduled

• From Room and To Room properties are labelled as 'Not Available'.  In the Autodesk help files, they are labelled as 'For Future Use', which is a promising sign for something to come.

It is possible to add your own Project Parameters to Path of Travel lines

• These must be instance properties
• If you try Type properties, the Lines category is not available

View Filters

View Filters can access the all the same system properties (except Count)

• Path of Travel Lines can be filtered by such things as Length, which would be very useful for highlighting paths over specified limits.

• Path of Travel Lines can be filtered by Linestyle, for separating different kinds (in the absence of Types)

Since Path of Travel elements are actually Detail Lines, they are view dependent, so it unlikely that you would want to hide them in a view, so its more likely that you would want to override properties.

However, you could just do that with Category overrides - so I am not sure you would use view filters for this, unless you want them with halftone.

Obstructions

The settings menu lets you remove categories from the calculation.  By default the door category is removed (checkbox ticked).
I would like to see the standard filtering ability for the category list (its missing from the dialog box)

• By Discipline
• Show only selected

Path of Travel Calculations

The Autodesk Revit Help Files have a section describing how the paths are calculated.  I am not quite sure I understand it all - particularly as it only seems to be talking about plans, rather than how it checks for obstructions in 3D.
Path of Travel Calculations

Conclusion

This is obviously a first pass at what should be a very useful tool at some time in the future.

I am very pleased that it seems like Autodesk have been careful not to tailor this tool to any particular country or style of doing Escape Plans / Fire Safety, which is a very good thing (NB. Area plan calculations are a real pain for anyone outside the USA, as an example of country specific coding).  In fact the tool is sufficiently general that it could probably be used for all sorts of other purposes.  Presumably the tools have been made available in the API so that developers can create country specific addons?

In its present format, it does have quite a few limitations, which will hopefully be addressed in future iterations:

• The Dalek conundrum - how to get up or down stairs
• No system 'Comments' property.
• Type properties not available (in Project Parameters, or anywhere else)
• Users nominate Start point and End point - it does not allow us to nominate any intermediate points that we want to go through.  
• Perhaps Autodesk could create a way to link paths to allow this?
• It is not possible to move either the start or end point individually - it seems like you have to recreate a new one if you get it wrong first time. 
• What happens if you don't like the route that algorithm has chosen as the shortest route?  You may have good reasons for not wanting that route.  I would like to have the ability to either choose another option (Like Google Maps directions), or else to be able to nominate intermediate points, or even to be able to drag individual joint nodes between each segment.

Cartoon - With thanks to Birkett (Punch Magazine)

More On Path of Travel

• Follow Up Detail on Path Analysis.

Improvements to Path of Travel in point releases:

•  Enhancements in Revit 2020.1 - Move Start/End Points 

•  Reveal Obstacles - New Feature in 2020.1

• 
  Revit 2020.2 Add Waypoints