BILT Speaker

BILT Speaker
RevitCat - Revit Consultant

Wednesday, 17 July 2019

LRUG Computational Design LT in Revit

Pump up the Volume - Control Panel using Adaptive Components

Last week I did a presentation at LRUG (London Revit User Group) entitled "Computational Design LT" - using Revit as a design tool, with model changes driven by sliders (100% Revit, no Dynamo).  This was achieved by various methods, including Adaptive Components and Global Parameters.   This talk was largely based on presentations that I did at RTC/BILT conferences in Scottsdale, Arizona and Adelaide, South Australia: "Power to the People" (2016-7);  and "Pump up the Volume" in Chicago and Melbourne (2014).
Sliders Using Global Parameters

In previous blog posts I have documented most of the background research I did on Global Parameters (refer to contents page).  In future blogs I will add more descriptions of how this works.

Sliders by Design

Saturday, 1 June 2019

20th Time Presenting at RTC / BILT Conferences

RTC 2014 - Pump Up the Volume - Competition Entry

Last year this blog reached a milestone of 1 Million views.

This year I reached another milestone: Presenting at my 20th RTC / BILT Conference on various Revit topics.  At several of the conferences I did multiple presentations, so the actual total is more than 20.

For the record, here is a list of :
RTC & BILT conferences over the years:

RTC (Revit Technology Conference) grew out the Sydney Revit user group, started by Wesley Benn.  The first conference was organised by RUGS (Revit User Group, Sydney - the longest running Revit user group in the world).  As the conferences went from strength to strength, they were run by a company RTC Events, which has now morphed into DBEI (Digital Built Environment Institute).

RTC 2005 - Blue Mountains (West of Sydney), NSW, Australia 

The inaugural conference.
  • I missed this one, sadly.

RTC 2006 - Shoal Bay (North of Sydney), NSW, Australia

  • Attended as a delegate only - and learnt a huge amount about Revit.

RTC 2007 - Roadshow event held in Sydney, Brisbane, Melbourne, Perth (Australia) & Auckland (New Zealand)

  • 1.  I presented at the Sydney event: "Documentation in Revit"

RTC 2008 - Brighton Beach, Sydney,  Australia

  • 2.  Presented: "Revit Architecture - Advanced Modelling"

RTC 2009 - Albert Park, Melbourne,  Australia

  • Attended as a delegate only - the first year of having to submit abstracts (which I failed to do)

RTC 2010 - Manly Beach, Sydney,  Australia

RTC 2011 (Australasia) - Broadbeach, Gold Coast, QLD,  Australia

RTC 2011 (North America) - Huntington Beach, California, USA (NE of Sydney)

Inaugural North American conference
  • 5.  Presented: "Designing in Revit Using Parametric Formulas"

RTC 2012 (Australasia) - Northbeach, Wollongong (South of Sydney), NSW,  Australia

RTC 2012 (North America) - Stone Mountain, Alanta, Georgia, USA


RTC 2013 (Australasia) - Auckland, New Zealand (East of Sydney)


RTC 2013 (North America) - Bayshore, Vancouver, Canada


RTC 2013 (Europe) - Delft, The Netherlands

Inaugural European conference- one of my favourite venues/events

RTC 2014 (Australasia) - Albert Park, Melbourne,  Australia

RTC 2014 (North America) - Schaumburg (West of Chicago), Illinois, USA

RTC 2014 (Europe) - Dublin, Ireland

  • First international conference I missed

RTC 2015 (Australasia) - Broadbeach, Gold Coast, QLD,  Australia

RTC 2015 (Asia) - Sentosa Island, Singapore

Inaugural Asian conference

RTC 2015 (North America) - Washington DC, USA

  • Missed this one - 4 events in one year would be too much!

RTC 2015 (Europe) - Budapest, Hungary

RTC 2016 (Australasia) - Hunter Valley (North of Sydney), NSW,  Australia

  • Attended as a one-day delegate (taking a break due to presenter burn-out)

RTC 2016 (North America) - Kierland Resort and Spa, Scottsdale, Arizona, USA


RTC 2016 (Europe) - Porto, Portugal

  • Missed this one



In 2017, the name RTC was changed to BILT - as the conferences were no longer restricted to Revit

BILT 2017 (Asia) - Singapore

  • Missed this one

BILT ANZ 2017 - Adelaide, SA (West of Sydney),  Australia

  • 17.  Presented: "Power to the People - Global Parameters New Revit Feature"

BILT 2017 (North America) - Harbour Castle, Toronto, Canada

  • 18.  Presented: "Create Good Looking Organic Nurby Revit Content" - Massing in Revit

BILT 2017 (Europe) - Aarhus, Denmark

  • Missed this one

BILT 2018 (Asia) - Singapore

  • Missed this one

BILT ANZ 2018 - Fortitude Valley, Brisbane (North of Sydney),  Australia

BILT 2018 (North America) -St Louis, Missouri, USA

  • Missed this one

BILT 2018 (Europe) - Ljubljana, Slovenia, Denmark

  • Missed this one

BILT ANZ 2019 - South Bank, Melbourne, Vic (South of Sydney), Australia

  • 20.  Presented: "Choosing Standards from 50 Ways to Do That in Revit"

 Anyone notice a theme in the locations?  Beaches, parks, islands, bays, valleys . . . .

*NB. This list does not include the various ancillary events such as 'Data Days', DTS, BCS etc

Friday, 10 May 2019

Path of Travel Follow Up - Revit 2020

Following up on my previous post 'Path of Travel - The Dalek of Revit 2020' I have investigated one of the problems that I encountered the new feature while testing it.  This related to the path of travel not going around the sofa in the lower area living room.

What I should have done is look at the model more closely in 3D.  The living area (with dotted hatching on carpet) is 3 steps lower than the rest of the house in the Revit sample file.  The sofa is on the lower level, and only the back and arms protrude above the floor level of the rest of the house.

What Revit does in calculating the path is to calculate obstructions from the 'Bottom' height up to the 'Top' of the analysis zone, relative to the level of the plan view that you are in.  Any obstructions outside this height range are ignored.

What happens in this example is that the path of travel is calculated ignoring the change in level going down the 3 steps.  The bulk of the sofa is below the analysis zone, so the only thing the path will avoid is the sofa back, and the path happily runs across the sofa seat - even if you might have trouble doing so when running in a panic.

If you look closely, you can see a small kink in the path, steering clear of the sofa back.

If we select the sofa and raise its height so its fully within the analysis zone, .

When you update the path, then you may get the expected result with the escape path sneaking around the back of the sofa.

That space behind the sofa looks a bit narrow, so I wondered how Revit would respond if we make it even narrower - so I nudged the sofa a bit closer to the side wall, then updated the path again.

Now that is definitely a problem - no way could you sneak behind the sofa!  It seems like Revit is allowing a clearance around the sofa, but not the wall behind it.

As per my previous (Dalek) post, if you leave the sofa down on the lower floor level, then lower the Bottom height of the analysis range to anything less than 175mm, it fails when you try to update the path or to create a new one that crosses the 3 steps down into the split level living area.

What this tells me is that this tool is very much a work in progress, and we should probably wait until it is updated before trying to use it in anger on a real project.  It is interesting to note that the calculations evaluate the true 3D shape of any obstacles, rather than a bounding box - something that might catch you out in situations like this.

Thursday, 18 April 2019

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.


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.


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


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)

Refer to Follow Up Detail on Path Analysis.