BILT Speaker

BILT Speaker
RevitCat - Revit Consultant

Thursday 26 May 2016

New in Revit 2017 - In-Place Stair Category

One of the new features in Revit 2017 that I do not like is the ability to create in-place families with the 'Stairs' category.  I pleaded with the Autodesk development team not to include this in the software but too many other people wanted it, so I lost out.

Do Not Use it!

Whatever you do, do not be tempted to use this new feature - it is a really bad idea.
  • In-place stairs do not host railings.
 You don't need any more reasons after that!  But here are some anyway:
  • You cannot use any of the stair features like stair numbers or arrows
  • You cannot mix and match in-place with component stairs
  • You can create unusual shaped stairs using the component sketch tool 
  • It was much faster for me to model the staircase shown above using the component sketch tools than it was to model it in-place by creating forms and cutting with voids. 
  • In-place families are a (necessary) evil in Revit - but they cause so many problems.  They should only be used as a last resort when absolutely nothing else will do the task.
  • If you move or copy an in-place stair, it does not move the elements (including forms) within it - so you have to edit the family to repeat the move process
  • In-place families included within groups just make duplicates of the family - they don't necessarily move when the copies of the group move;  they don't update in the duplicates if you update one
  • The list could go on . . . .
If you want to know more about how to create unusual shaped stairs using the component sketch tool, please attend my presentation 'Making Component Stairs Work For You' at RTC North America on July 16th 2016 in Scottsdale, Arizona.

Saturday 21 May 2016

Revit 2017 Install Take 2 - Using Physical Media

After my first attempts to install Revit 2017, I have just tried again, as my regular laptop came back from being repaired.  This time I used physical media to do the install, as I found it to be so painful to download/install from the Autodesk website:

Ordering Physical Media

The biggest obstacle to overcome is your willingness to pay the new 'Nominal Fee' (Aus$40) for something that was previously part of your annual subscription - so we now have to pay for something that we've already paid for!  What a cheek!  Autodesk have made some lame excuse about most people preferring the convenience of downloading the software - well that might be true if you could just download it and keep the install files locally and reuse them.  But you cannot - I tried it!
I copied the (download) unpacked install files from the C:\Autodesk folder on my old computer and put them in exactly the same location (with the same two folder names) on my repaired laptop.  Then I tried to run setup from there - but it gave an error message saying that either the connection had broken (back to Autodesk account) or the install file location had changed.  Everything I tried gave the same result.  After wasting a lot of time I decided to cough up the $40 and purchase the physical media - I was not about to waste a whole lot more time downloading again.

On the Autodesk Account, under 'Revit' the order Physical media option is hidden away under 'More Actions' as 'Get a physical copy'.
Previously, when I tried to order physical media from the Autodesk account website, it failed - giving an error message.  They seem to have fixed that now, so I was able to order the DVD, and it duly arrived a few days later, all the way from Singapore.  To add insult to injury, the website charged an additional 10% GST, despite the fact that the importer was registered in Ireland and media shipped from Singapore (overseas orders do not normally incur goods and services tax in Australia).

Install from DVD

I normally copy the contents of an install DVD onto the C: drive just to speed up the actual installation - and so that I don't need to find the DVD in order to (re)install any missing components.  This worked just fine, and setup ran happily from the C: drive this time.
I may be mistaken but it also seemed to give me much better control over what was actually installed (or maybe I just missed the options first time around during the download process, fondly imagining that I would get a chance to change them later?).
This time I was able to choose:
  • Country
  • Omit the MEP Fabrication (both imperial and metric)
  • Discipline - can be 'All', 'Construction', 'Architecture', 'Structure', 'Plumbing', 'Mechanical', 'Electrical' etc.  This means that you cannot choose a combination (say M,E + P or Architecture + Structure) - you would have to choose 'All' or just one - so I chose 'Architecture' just to keep it simple.
  • UK Terminology.  It still amuses me when I choose "the British English", which is clearly grammatically incorrect in British English, but perhaps just fine in Chinglish?

As I had previously installed with Australian content, I chose not to install any content this time around - normally it gives you a warning, but I don't remember one this time.

The install process went smoothly - no nasty error messages that I had with the online install (IDP Alexa or DXSetup), where my Anti-virus software didn't like the install process.  Several things could not be prevented from installation - the Autodesk Desktop App being one of them

Autodesk Desktop App 

 This is billed as a "Powerful cloud-centric software delivery solution".  The phrase 'cloud-centric' is enough to put me off using it - why are Autodesk obsessed with putting everything on the cloud?  Don't they realise that not everyone in the world is connected to the internet all the time - if you don't live in the USA, the internet is not always reliable, fast or available all the time!
Aside from that, I have heard from several reliable sources that the 'Autodesk Desktop App' is not a good or reliable piece of software.  In fact it may be a liability - so I intend to uninstall it immediately.

Installed Folders

Since I chose not to install the MEP Fabrication tools nor any content, the installed folders are a lot cleaner than last time.  Of course, I was able to copy the libraries and templates across after I had tidied them up and reinstated all the missing family templates, and removed the unwanted language options.
However, I did notice one piece of  bloatware that should not have been installed, considering that I specifically chose an 'Architectural' discipline install - in C:\ProgramData\Autodesk:
However, if I had been allowed to install a combined discipline of 'Architecture and Structure', that would have been very welcome.


The install process from physical media was dramatically better than the painful online download/install experience.  The only downside was having to pay for software that I had already paid for.  This morning, while Revit 2017 was busy installing on my laptop,  I went to the upmarket Sydney suburb called 'Double Bay', but universally referred to as 'Double Pay' - how appropriate!

Saturday 7 May 2016

New Tangency Locks in Revit 2017

One of the new features in Revit 2017 that I am most excited about is "Tangency Locks".  The reason is that I have spent many hours, days and weeks trying to control arcs in Revit.  Now we have another tool to help with this.


The Autodesk Revit Help files state:

"Tangency locks: When sketching in the Family Editor, you can now place tangency locks to model lines, symbolic lines, reference lines, or sketch lines. This enhancement eliminates the prior need for complicated formulas and parametric associations to drive tangential relationships"

What on earth does that mean?   If you have tried to parametrically control arcs in Revit sketches, you might have some inkling, but otherwise how would you know what a 'tangential relationship' means - it could be something quite intimate if you misread or mistype it!

The 'Whats New' help file neglects to mention that Tangency Locks can also be applied to system family sketches in the project - floors, ceilings etc.
If you delve into the details of the help files it explains how a tangential lock can be applied - it even has a little diagram, which is a rarity in the help files.  However, it does not actually explain what they do or why you might use them.

The easiest way to describe it is to look at an image of what might happen to a modified sketch in Revit without a tangential relationship.  Here is a Revit sketch with transitions from line to arc to line where each transition is a perfect tangent:
Tangential transitions from line to arc to line
So what happens when the sketch is modified?  Well that all depends on what the relationships are between each element - what is constrained and how;  what is aligned and locked to what else.  It is not easy to know or predict.  Sometimes the relationships or constraints are obvious - maybe the little lock symbol shows when you select a line, or there is a dimension, which shows a lock symbol when you select it.  These are 'Explicit' constraints, because someone made the effort to set them up.  There can also be 'Implicit' constraints that are hidden away in the system - Revit follows certain mysterious rules in managing this.  For example, lines/arcs that are placed close to reference planes often become associated with them and follow them if the reference planes are moved.  How does Revit maintain those relationships?  Well, it has some hidden dimensions, called 'Auomatic Sketch Dimensions' - if you switch their visibility on, it often explains a lot about why your Revit sketches behave as they do.

In the above example, let us assume that the joint between the top line and arc is locked to the intersection of reference planes, and that the arc radius is locked.  If the other line is moved, the first tangential relationship cannot be maintained without breaking some constraint - so we get a non-tangential relationship.  The second tangential relationship may or may not be maintained - in this example it is.
In the example above, if you wanted both ends of the arc to remain at tangents to the straight lines, something would have to give way - either the radius has to change or the locks to the reference planes would be lost.  This is important to understand when looking at the new feature of Tangency Locks.

Tangency Locks

In previous versions of Revit, it was possible to retain tangential relationships, but in order to do so we had to undertake some serious trigonometry to calculate where the centre of each arc would be, and then the start and end points of each arc.  If the lines are not orthogonal, it gets much more complicated, and pretty soon gives you a headache.

Formulas - trigonometry to maintain tangents (a simple example)

In 2017, we now have the ability to click on a tangency padlock symbol to enforce each tangential relationships.  Sounds easy - and it is;  but you need to think quite carefully about what you are doing, and what might subsequently happen.
As soon as you click on one of those padlocks, it has a knock-on effect to the other ends of the line and arc (or two arcs) - when a line with a tangent lock on it is moved, the tangent is retained, and maybe another line is moved or a constraint has to break

Tangent locks are very strong!  They seem to trump everything else.  Or perhaps that phrase is now too political?  I should say that they over-ride other locks and constraints.  If you are editing a sketch and move something that has tangency locks on it or adjacent to it, Revit may tell you that a constraint is broken, or it may just move something that was previously in a stable location (prior to adding the locks).  For example, if you rotate a sketch line about its start point, and that start point has a tangency lock to an arc, Revit will rotate the line as you asked it to do but it will also move it to maintain the lock - it is logical but may surprise you.

Lock Display

When you select a line within a sketch, Revit will display padlocks for all the alignment locks within the sketch - very useful to see them all at once (even if a bit messy sometimes).  However, tangency locks will only display when you select a line or arc that has locks on it - so you cannot see all of the locks at once.  Selecting multiple arcs will cause no locks to be displayed.
It is important to note this difference, as it may be very hard to track down the tangency locks.  'Reveal Constraints' does not help with this, as it does not show constraints within a sketch.

Example 1

Here is an example of 'before and after' applying tangency locks on a sketch:
  • In this sketch a parametric angle has been set up to control a reference line.  The angled sketch line is aligned and locked to the reference line.
Sketch with no tangency locks - before angle change
  •  When the angle is changed, Revit maintains the arc radii, and the alignment lock - so what breaks is the tangencies.  The end result is horrible!
Sketch with no tangency locks - after angle change
  •  In v2017, tangency locks can be applied to each end of all the arcs.  In this example, all of the straight lines are aligned and locked (to references or have locked dimensions).  So what changes when the angle is modified is the radii of one of the arcs (top left).
Sketch with tangency locks - after angle change
  • This works fine for various configurations, but not all

  • Eventually something breaks - in this case it is probably the line on the right becoming less than 0.8mm long.  The warning message is not very explicit when you expand it, although you might be able to track its ID.
  •  If this error occurred within a family in a project, it would just say that it could not create type - so you need to do a lot more testing and flexing of families that have tangency locks.

Example 2

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, the radius is reduced to compensate.

I complicated the simple sketch above a little more by adding parameters to the radii, and it had some unexpected consequences:  it had 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, even though they are supposed to be controlled by a parameter, 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: 

I guess we need to figure out a way to actually lock the radius parameter.  Or perhaps it is a bug?


If you apply tangency locks to an old sketch, you may find that you introduce all kinds of constraint problems, so you need to test and flex it immediately after applying the locks - this will hopefully allow you to understand the effect of the locks.  You might then find that lines may move, or radii change where they were previously stable - so you might need to add some more constraints or locked dimensions.  The more tangency locks that you apply to a sketch, the more testing you need to do - to make sure that you have not introduced new constraint problems.  However, it should mean less trigonometry that you need to do!

I think that we will have to get used to a different way of managing constraints in sketches - it might be a little frustrating at first but I'm sure that the pain will be well worth it, and a lot of time should be saved in the future.