Thursday, 2 January 2014

Spiral and Curved Revit Stairs

Loretta Chapel, Santa Fe

Creating Curved and Spiral Stairs

New Stair Tools were introduced in Revit v2013 – these included two methods to create a curved stair run by component:

Full-Step Spiral

This tool requires two mouse-clicks to place a curved or spiral stair – the first click is for the centre, the second for the first riser location & stair radius (inside, centre or outside depending on your Location Line setting). It does not require a third click for direction – this will normally be counter-clockwise, unless you press the space-bar first. It will place a run with the full number of risers required to meet the stair base and top level properties that you have set.

It will allow the top of a spiral to go over the base (ie. More than 360 degrees). The pop-up help note says “Use to create a spiral run that is greater than 360 degrees” – this is a little misleading as it can also be less than 360.

Some issues to watch out for when placing spiral stairs:
  • Spiral stairs creation does not snap to orthogonal, so make sure you place a reference plane first so it can snap to that - to get centre and first riser aligned orthogonally.
  • Press the space bar after the first mouse-click to flip the orientation (it is too late to flip it after the second mouse-click).
  • If you press the “Flip” command after placement, it will only reverse the direction (swap first/last riser), but will not mirror its location.
  • Make sure that you get the radius correct first time, because it is almost impossible to change it accurately afterwards in v2013 (its better in v2014).

Center-Ends Spiral


This tool requires three mouse-clicks to place a curved or spiral stair – the first click is for the centre; the second for the first riser location & stair radius (inside, centre or outside depending on your Location Line setting); the third click controls the direction and the end of the run.

It will not allow the top of a spiral to go over the base (ie. It must be less than 360 degrees) – if you try to go past the start, it just reverses the direction of the stair and reduces the number of risers in the run. However, it can be extended past 360 later on. Alternatively you can add a second Center-End spiral and Revit will add a landing between them - by default the options bar setting will be ticked so that this happens automatically.

Modifying Curved Stair Components   

Controls for changing arc and spiral stairs are somewhat limited:
The arc /spiral radius cannot be changed accurately after placing it (see below) - using the circular shape handle in the centre of the run will allow you to drag the radius value but it will not snap to anything, so it is impossible to get a precise value. 


The Flip command reverses the direction of the stair.  This is available from the ribbon during edit mode or else when the whole stair is selected not in edit mode - displays as a small arrow when the stair is selected.

Align Tool

You must be in Edit mode to use this command on individual stair components (otherwise the whole stair will move).    It will behave differently depending on what you select to align and what the relationship is between linked components.

  • If you try to align a curved run edge or centreline, it will not select the curved edge at all - ie. it can't be done.
  • If you align the end point of a riser line to a curved line, it will move the run , but in the process will change the radius of the stair and none of the other riser ends will align - so don't try this!
  • if you try to align the ends of a curved run, it should work providing the reference line is radial from the centre of the arc; but the landing length (between runs) will be changed
  • It will not align the sides of curved landings.
  • if you align a landing end (where it meets a run), it will most likely move the whole landing, which in turn will move the associated runs, in effect moving the whole stair. Sometimes with a landing it may It gives a cryptic error message.

Shape Handles

There are four different types of shape handles that you get on curved stairs, and they each behave differently, and their methodology also depends on whether other components are joined on:

Circle handle in middle of a curved stair run.
  • Dragging this circle will adjust the radius of the arc defining the centreline of the stair run.  It does not change position with the location line – it is always the centreline of the stair. 
  • This will not snap to any increments or elements, giving random dimensions, which renders it effectively useless – hence you can never accurately change a curved stair radius after placing it in v2013. 
  • This is the only way to change the radius of a curved stair in v2013
  • Refer to Temporary Dimensions for an alternative method in v2014 .
  • If you have a landing on a curved stair, attempting to use the centre-circle shape handle will also move the other run (not selected one) thus distorting the landing.

  • Side-Shape handle arrows behave like the centre circle – they won’t snap to elements or increments so they are next to useless.
The dot and arrow handles at the base and top of stairs behave like straight stair runs: 
  • Dot shape-handle will add/remove risers from that run.  Warning: height of that end of the run is adjusted so the base could be up in the air;
  • Arrows will add/remove risers from that run but remove/add the same number to the other end of the stair.  Height of ends will not change but location in plan will change.

Temporary Dimensions

Sometimes the temporary dimensions that you get when selecting a stair component will not work, when you expect they would:
  • Spiral stair run width cannot be changed by its temporary dimension – you must use the properties.
  • Spiral stair radius cannot be changed by temporary dimension in v2013 but can be in v2014.
  • If a curved stair has a landing on it, it is not possible to change the radius of both runs together, so in v2013 it will not be possible to adjust at all – just delete and start again (and lose all the annotation etc)!   
  • In v2014 you can use the following procedure:
  • If the stair has a landing, you need to adjust run by run, which does some interesting things to the landings in the process
  • It also seems to change the run width, but do not be alarmed - just reselect the run to see it has the correct width
  •  Once the radius is adjusted on the second run, it corrects the landing shape
  •  However, the landing length is now wrong
  • This needs to be adjusted by rotating one of the runs or else by dragging the shape handle arrows on the landing.  Most likely you need some construction lines first, in order to get the landing length right, in which case you could use the align tool to get the runs in the right place (do not select the landing).

Move Command         

This is not particularly useful for changing curved stairs:
  • Moving a landing will move the whole stair as one;
  • Moving a run will distort the landing.

Rotate Command

This is useful for adjusting curved/spiral stairs:
  • Rotating a curved run about the arc centre-point will reduce or expand any attached landings.   Most likely you will need to set up some construction lines to snap to so that the landing length is correct.
  • Rotating a landing about the arc centre-point will bring both runs with it, effectively rotating the whole stair.  

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