Weird Railing Stuff - part 7 - Support Spacing

It amazes me that very few Reviteers make use of the 'Railing Support' capability that we have had in the software for over 5 years now.  In fact, a very large percentage of users don't even know they exist
Here are some possible reasons why that is the case:

• If you upgrade a project with the old style railings in it, they are not converted to the new style railings, so you cannot use railing supports in them.  To achieve this, you have to copy a new railing type into your project, then swap the old family type to a new one to get access to the support functionality.
• The metric project templates provided by Autodesk do not include any railings that use handrail supports (this includes the Australian and UK templates);  they do have some support families - but if you don't know how to use them, you'll never figure it out by playing around with the railing samples.
• The sample files that you can download from the Autodesk Knowledge website include only the old method of using balusters to look like handrail supports - and that is the imperial unit sample file, which you would expect to be the most likely one to be updated when the software was changed (The metric version would have no chance, even if you could find it on the Autodesk labyrinth-site).  I wonder if anyone at Autodesk knows what QA means?  'Quality Assurance' is the correct answer, not 'Quick As (get this out the door)'.
• The settings for adding supports are buried deep as type properties of a nested family.  The chances of finding this are slim - although that has improved recently with the ability to get to a handrail family properties directly from the railing type properties dialog box with one mouse click.
• The methodology for setting up handrail supports is mind-bogglingly complicated and counter-intuitive - and it is all type-based properties hidden inside handrail families nested into the railing family.
• Even when you have set up the supports in a handrail family, you have to remember to choose left or right (for the handrail) in the railing family, otherwise nothing shows up.

Handrail Support Spacing

Once you have figured out how to set up Handrail Supports in a railing,you will obviously want to control the spacing - first the initial spacing, and then changing the spacing.  There are at least two weird things you need to know about this - the first is how illogical and inconsistent the spacing properties are.  The second weird thing relates to moving the supports - to be dealt with later:

Spacing Properties

Do you think it is weird that baluster spacing and handrail/top rail extension length properties are measured in plan distance regardless of the slope of the railings, while support spacing is measured along the actual length of the handrail whether it is horizontal, sloping, vertical or going round a twirly flourish at the end?  Whichever one is correct, it is weirdly inconsistent.

How would you measure the support distances on this handrail?

In the Handrail type properties, you have the typical Revit options (plus a special one):

• None
• Fixed Distance
• Align With Posts
• Fixed Number
• Maximum Spacing
• Minimum Spacing

Unfortunately these are not consistent with each other, and none of them will give you the outcome that you desire (unless by a fluke the spacing just happens to work for your stair):

1.  'Fixed Number' does not put supports at the ends of the railing;  the spacing varies depending on the overall railing length, and the number that you put in - NB. the number is a type property of the handrail, which means that you most likely need a unique handrail type and a unique railing type for every single instance of the railing.
It seems that the supports always use centre justification for this - it is greyed out and you can't change it;  also, the greyed out value for spacing is just a remembered value from the previous settings, and is misleading here.  Revit does not report back to you what the actual support spacing is on each handrail instance.

If you have a free end handrail, you would typically want a support close to the end (but not exactly at the end).  You don't get a support anywhere near the end, unless you put in a ridiculous number of supports, like 50 in this example.

Fixed number does not put supports at the ends

If you have an extension to wall or floor, then this option makes sense, however, the spacing includes the length of the extension, measured along the handrail, including vertical length for a floor extension.  The example below, with a wall extension is the one and only situation where Revit gets the support locations close to what you might need, albeit that you need a separate type for each different number of supports.

2.  'Fixed Distance' only puts a support at the start or end of the handrail if the justification is set to Beginning or End;  the distance at the other end is pot-luck depending on the overall handrail length.  If the justification is 'Center', then the distance from the start and end again depends totally on the overall length of the handrail - so it is luck of the draw, but it will be the same at each end.
The calculated distance includes extensions.

 3.  'Maximum Spacing' always puts a support exactly at the start and end of the handrail; justification is not an option here - it is greyed out (and set to center).  Just imagine sending this drawing to a builder or fabricator - you'd be laughed off the site.

Revit does not take into account whether an extension with a wall or floor fixing is chosen - it still puts a support in place at the very end, just where it is fixed to the wall/floor.

4.  'Minimum Spacing' behaves just like the Maximum Spacing settings, although the actual spacing will be different.

5.  'Align with Posts' is an interesting option - I don't get why you would use it, unless your posts are non-supporting in themselves.  If you do use it, you have no option for supports between the posts, so what good is that?  I would have thought the option should be 'Align with Posts & Maximum Spacing Between' and suchlike.  Or 'Maximum Spacing Except at Posts' etc.

With all of these options, you have the opportunity to unpin a support and move or delete it; [Edit - thanks to Peter Schiettecatte for pointing this out:] but you can only add additional supports by unpinning an existing one and copying it along the handrail (a clever but not too obvious workflow).  However, once you have done this, it takes just one innocent (or stupid) click on the 'Reset Railings' button to lose all that hard-won support over-ride spacing.

The Solution

What we really need to solve some of these issues is to have consistency in how the spacing is applied (at ends); and the ability to set start and end indent properties for handrail support spacing.  These would operate rather like the equivalent properties on a 'Divided Path', although I guess they'd need to be type properties to be consistent with all the other handrail properties (Oh, how I wish most of those were instance properties in the actual railing)

If you think this is a good idea, please go to the official Revit Ideas website and vote up my idea on this.

 More on this subject

• Weird Railing Stuff - part 7a - Support Spacing Postscript
• Weird Railing Stuff - part 8 - Moving Handrail Supports  
• Weird Railing Stuff - part 9 - Handrail Supports on Multistorey Stairs (Revit v2018+)

How to Indent a Revit Repeater on a Divided Surface

In a recent post by Andy Milburn over on Shades of Grey, he mentioned that it is not possible to indent the edges of a divided surface.  Well, that is absolutely true - Divided surfaces are unlike divided paths, which have an indent setting so that you can push the start or end nodes of the path in from ends of the underlying path.

Divided Path indent settings

The implication of this is that when you use a divided surface to generate a "Repeater" in Revit, the repeated adaptive components will overhang the edge of the divided surface.   In the example below, a one point adaptive component is placed on a node of the divided surface, then repeated - since the adaptive component consists of a cylindrical extrusion centred on the point, it is repeated to all nodes of the divided surface.

 

Since you cannot indent the edges of a divided surface, how can you prevent the repeater overhanging the divided surface?  If you made the extrusion offset from the adaptive placement point you could make it indent on one or two sides of the divided surface, but then it would overhang even more on the other sides.

However, in Revit there is usually a way to achieve what you want, so I attempted to find a way to indent the repeater, if not the nodes of a divided surface:

How to Indent a Repeater Pattern

You have to use some tricky thinking, and control where the repeater components will land - and prevent it from placing any part of the extrusion in the adaptive component on the edge nodes.
One way to do this would be to create a four point adaptive component:

• First create a new adaptive component and place four points in a square arrangement
• Make the points adaptive
• Join the four points with four reference lines

Now you need to set out a centre point to host the geometry so that it remains centred whatever the arrangement of placement of points

• Place four more points on the mid-point of each reference line (watch for the triangular snap symbol
• Join those four points with two more reference lines
• Place yet another point on one of the central lines

• When you select the point, it will have an option (on the Option Bar, no less) to host it by intersection

• Select that option, then pick the other central reference line
• It will move the point to the central intersection.
• NB. On reflection, you could skip the last four stages and just have one central linking reference line with a single point on its mid-point.  However, you could this intersection technique for other situations - perhaps if your extruded geometry needs to be more complex than a cylinder (see later on).
• Select the central point and set its "Show Reference Planes" to "Always"

 

• Set the active Work Plane to the horizontal reference plane of the central point
• Place a reference circle centred on the point (assuming you want a cylinder)
• Give its radius a parameter

•  Select the circle and "Create Form"

•  Select the top facet of the cylinder and give its Positive Offset a parameter called "Height"
• Save and load the family into wherever your divided surface resides
• Place one of the components onto four adjacent nodes of the divided surface in the same order that they are numbered in the family (its good practice to always use the same convention - say clockwise, unlike the diagrams shown here!!)

• Select the adaptive component and click on the "Repeater" command (its the Array icons, but with the letter P on it)
• If you snapped to the nodes correctly it should create a regular pattern
• The extruded cylinders will be inset from the edge - however, they will only be inset by half the distance between nodes

• If you want the cylinders to be inset by the full distance between nodes, you'll need to be more tricky:
• Delete the repeater (you cannot dissolve it or alter its layout)
• Place a new component on alternate nodes in a square pattern
• The cylinder should then sit exactly over a node

• Select the component and "Repeat" it
• The pattern should spread over alternate nodes on the divided surface

• The spacing will then most likely be too big
• Select the divided surface and double the number of divisions (or half the spacing if it is set by distance)
• Oops - we've now ended up with the same indent as before, so we may need to try another trick

• The answer here is to coerce Revit into doing what you want by indenting the initial placement of the component 
• Make sure that the first placement node you select is one node in from both edges

• Select the component and repeat it

 

• This will only work if the number of divisions is equal;  it will probably no longer work if you start playing around with number of divisions after repeating the component - so it pays to set the number of divisions correctly to start with.

If you want to be really clever, you could go back to the original four point adaptive component and give it some reporting parameters and use them to drive the cylinder size depending on the divided node spacing