BILT

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Monday, 18 December 2017

Weird Railing Stuff - part 10 - Split railings

[Edit:  Revit 2019 has a new feature that allows you to split a railing - but all it does is to break the selected railing into two separate pieces that no longer relate to each other.  They can then be separately edited.   But just supposing you wanted to have a single railing element that has a gap in it?  Read on . . . .]
Have you ever tried to create a Revit railing with a split or break in it?  You'd have seen the warning that tells you it is not possible in Revit:

Split Revit Railings

Well, there is a way to do it - yes you can split railings (with lots of provisos, of course).
WARNING: this is another crazy workaround, so use it with caution . . .

In this example, a railing runs through a column, which is not desirable


You may want to break the railing and have a gap either side of the column

The first thing to do is edit the path of the railing, remove the top segments and stop it short of the column by say 50mm.



Once the top part of the railing is removed, Tab-select the 'Top Rail' (or Handrail) - it is important to select one of these sub-elements, not the overall railing.  NB. if your railing does not have either of these sub-elements, this technique won't work (eg. old style top rails)

Once selected, click on 'Edit Rail'

Then click on 'Edit Path' for the Top Rail

This will allow you to add lines to either the top or bottom end of the Top Rail element; but first it is important to set the workplane depending on whether you are adding to the beginning/bottom or end/top.

Select the name of the workplane.   I don't think that either of the 'Pick' options work here.

The workplane will be parallel to the first or last segment of the overall railing - so you'll need to work in either a 3D view or an elevation/section view.  It may be easier to start in 3D so that you can see exactly what you are doing and where.

This command is not explicit about what is going on - in fact Revit is waiting for you to draw some lines, which will become extensions to the Top Rail (or Handrail)

These lines do not need to be directly linked to the ends of the Top Rail - in fact they can be almost anywhere (in the same plane as the end of the Rail).  Start drawing a line the other side of the column from the end of the railing;  at this stage it may be easier to go into a section/elevation view to ensure that it aligns with the railing on the other side of the stair (but keep an eye on the active workplane).

Trace over the other railing (it should snap to it).

Once the Top Rail extension is complete, it will have a gap where the column is.


Be warned:  This is an extension to the Top Rail only - so balusters will not be attached to the underside of the extension.

Supports will not be attached to a Top Rail, so if you require supports on the extension, make sure before you start that your railing has a 'Handrail' sub-element, and add the extension to the Handrail, not to a Top Rail.  If you switch the railing to a type that does not have a Top Rail, the entire extension will disappear (if it was attached to a Top Rail in the first place).  Plan ahead!


Not surprisingly, this workaround is fiddly and not particularly robust - but I am showing it just in case it helps someone out.  In this example, it would probably have been much easier (and safer) to have two separate railings, but it might give people ideas about a use for this technique, so go for it.

Downsides:
  • Only works with a Top Rail or Handrail in the railing
  •  Top Rail and Handrail extensions are not interchangeable
  • Top Rail cannot host supports
  • Will not host balusters or posts beyond the split
  • Will not turn corners in plan
  • Will not automatically adjust heights/angles if the stair changes
  • Is quite confusing for anyone not familiar with railing extensions

Sunday, 3 December 2017

Weird Railing Stuff part 9 - Handrail supports on Multistorey Stairs

At first sight it seems that the new Multistorey tools in Revit look like a significant improvement over the old method.  However, as you delve deeper, there are some new problems that have been introduced with the new feature.

Weirdness #1

Once a regular component stair has been converted to multistorey that process cannot be reversed.  There is no command to 'Reset Stair' or 'Convert back to single storey'.  You can go to the 'Disconnect Levels' command, and select the other levels - this reverts it to a 'Single Storey Multistorey stair' - but it still identifies as a multistorey stair in the properties


So what, you might think?  Well, you can manipulate a multistorey stair by tab-selecting the stair inside the 'multistorey group', but that could be very confusing.  The more significant issue is what it does to railing supports:

Weirdness #2 Railing Supports

If you have a stair that has railing supports, and then you convert the stair to Multistorey it does something strange to the supports.  The original level stair railings behave normally - you can select a railing support and it will be pinned.

You can unpin individual supports then move them, swap to a different type or delete them


On the other levels, you can select the supports but they do not have a pin icon.  However, you can actually move, copy or delete them;  what you cannot do is swap their type (it is greyed out); nor can you change the hand clearance property.  They are in effect in some middling state between pinned and unpinned.

If you modify any of the railing supports, you can 'Reset' the railing so that all moved or deleted supports are reinstated to their original position.  Copied supports vanish.   

You might expect that supports on the original stair railing would become pinned again.  Well, not exactly:

Weirdness #3

If you 'Reset' the railing on the original stair level, it actually converts it to the strange middling state where none of the supports are pinned any more but there are reinstated to the original locations.


The moral of this tale is that you should probably try to adjust all the supports before you convert a stair to multistorey, especially if you want to swap any support types.  If that is not possible, you may still be able to do what you need to the supports after making the stair multistorey - notwithstanding all the other painful issues with railing supports.  One thing is sure - you will be confused.