Stair settings: Geometry tab

1. Click the Geometry tab to set both basic and detailed stair geometry based on the configuration selected on the General tab. The geometry parameters automatically influence each other; entering a few desired parameters causes the remaining parameters to adjust accordingly. Not all geometry parameters are available for all stair configurations; only the relevant parameters display.

Parameter	Description
Lock button	For any parameter, locks the parameter value, forcing the other parameters to recalculate to automatically adjust
Link button	Links stair flight widths so that they are set to the same value automatically; enter a value for one of the widths, and click Link to enter the same value for all linked flights
Total Rise: By Value or By Layer Elevation	Sets the floor-to-floor height of the stair by either a value or by layer elevation settings of the layers/levels it connects. If by layer elevation, the Total Rise By Layer Elevations dialog box opens; see Step 2.
Tread Depth(G)	Specifies the average depth of the stair tread, measured from the face of the riser to the face of the next riser. Also known as the “going.”
Riser Height(R)	Indicates the average height of the stair risers
Step Length(2R+G)	Displays the step length, which is calculated as 2 * the Riser Height (R) + Tread Depth (G)
Stair Width	Sets the overall width of the stair
Stair Width 1/2/3/4/5	Sets the width of each flight of stairs
Length	Specifies the total length of the stair, measured from the nosing of the starting tread to the end of the last tread
Walk Line Length	Indicates the length of the line that determines the direction of the stair and is the critical line from which the tread depth, oblique dimensions, and other values are calculated
Num. of Risers	Specifies the number of risers for the stair
Draw Top Tread	When enabled, the top tread is drawn; its parameters can be specified independently from the rest of the stair. Select the parameter from the list, and enter its value.
Min. Inside Tread Depth	Specifies the minimum allowable tread depth value for oblique, winder, or fixed angle winder stair treads
Walk Line Offset Options	Sets the walk line location. ● Walk Line by Offset: Sets the distance to offset the walk line from the inside of the stair; enter the offset value. ● Walk Line on Center: For stairs with fewer than two stair widths, sets the walk line offset to 0.5 times the stair width. ● Walk Line Centered on All Flights: For stairs with several flights, sets the walk line offset to 0.5 times the stair width, centering the walk line for all flights. If the stair has different flight widths, the walk line displays centered for all flights, but the calculation of treads and winders is based on the first flight only. ● Walk Line Centered on First Flight: For stairs with several flights, sets the walk line offset to 0.5 times the stair width. For stairs with winders, the walk line is centered based on the first flight only.
Oblique Bottom Tread	Offsets the distance of the front edge of the first tread from the start of the overall length of the stair (as measured along the walk line)
Oblique Top Tread	Offsets the distance of the front edge of the last tread from the start of the overall length of the stair (as measured along the walk line)
Top/Bottom Treads	Opens the Top/Bottom Treads dialog box to access certain parameters: ● Draw Top Tread: Draw the top tread and sets the parameters independently from the rest of the stair. ● Minimum Inside Tread Depth: Specifies the minimum allowable tread depth value for oblique, winder, or fixed angle winder stair treads. ● Oblique Bottom Tread: Offsets the distance of the front edge of the first tread from the start of the overall length of the stair (as measured along the walk line). ● Oblique Top Tread: Offsets the distance of the front edge of the last tread from the start of the overall length of the stair (as measured along the walk line).
Num. of Risers	Sets the number of risers for the stair
Num. of Risers 1	Sets the number of risers for the first or bottom flight of stairs
Num. of Risers 2	Sets the number of risers for the second or middle flight of stairs
Num. of Risers 3	Sets the number of risers for the third flight of stairs
Num. of Risers 4	Sets the number of risers for the fourth or top flight of stairs
Landing Length 1	Indicates the landing length
Landing Length 2	Sets the length of the second landing
Side 1	Indicates the overall outside length of the stair, as measured from the start or bottom of the stair to the outside corner of the landing
Side 2	Indicates the overall outside length of the stair, as measured from the outside corner of the landing to the end or top of the stair, or to the outside corner of the next landing
Side 3	Indicates the overall outside length of the stair, as measured from the outside corner of the landing to the end or top of the stair, or to the outside corner of the next landing
Side 4	Indicates the overall outside length of the stair, as measured from the outside corner of the landing to the end or top of the stair, or to the outside corner of the next landing
Side 5	Indicates the overall outside length of the stair, as measured from the outside corner of the landing to the end or top of the stair
Offset 1	Specifies the distance from the front edge of the landing or last riser of the first flight to the inside corner of the first landing
Offset 2	Specifies the distance from the inside corner of the landing to the back edge of the landing or first riser of the next flight
Offset 3	Specifies the distance from the front edge of the landing or last riser of the second flight to the inside corner of the second landing
Offset 4	Specifies the distance from the inside corner of the second landing to the back edge of the second landing or first riser of the next flight
Offset 5	Specifies the distance from the front edge of the landing or last riser of the third flight to the inside corner of the third landing
Offset 6	Specifies the distance from the inside corner of the third landing to the back edge of the third landing or first riser of the next flight
Outside Diameter	Sets the diameter measured from the outside of the stair
Inside Diameter	Sets the diameter measured from the inside of the stair
Sweep	Sets the angle of the arc formed by the walk line

2.If setting the stair Total Rise by layer elevation instead of by a specific value, the height of the stair can be constrained by layer or story elements at its top and bottom boundaries; the lower floor and upper floor indicate the two stories the stair connects. Adjusting a bounding element causes the height of the stair to automatically change accordingly.

Parameter	Description
Top Bound	Sets the vertical reference that determines the top of the stair. The Layer Wall Height value is set by the design layer (see Setting design layer properties). Alternatively, the top of the stair can be bound by one of the story levels defined for the story or the story above it. By setting the top of the stair to a level type, if the elevation of the associated story changes, the height of the stair changes automatically to match.
Top Offset	Sets the offset of the top of the stair from its specified top bound height
Bottom Bound	Sets the vertical reference that determines the bottom of the stair. Alternatively, the bottom of the stair can be bound by one of the story levels defined for the story or the story below it. By setting the bottom of the stair to a level type, if the elevation of the associated story changes, the height of the stair changes automatically to match.
Bottom Offset	For the bottom of the stair, sets the offset from its specified bottom bound height
Z of Top Bound	Displays the elevation value of the stair’s upper boundary
Z of Bottom Bound	Displays the elevation value of the stair’s lower boundary
Calculated Total Rise	Displays the calculated total rise value for the stair based on the stair’s upper and lower boundaries

The lower preview graphic displays a detailed section/elevation view of the treads and risers, and indicates the current rise angle.

● Click an upper or lower tread to set the oblique tread parameters for the highlighted treads.

● L- and U-Stairs have clickable red areas at the corner of the landing. Click each area to set corner parameters for the inside and outside corners of the landing. The Stair Landing Corners dialog box opens. For configurations that allow angles other than 90 degrees, enter the desired Length or Radius; the corner style parameters update automatically. For each corner, set the Corner Style to the desired angle, or round the corner by specifying a chamfer or fillet value.

● For Double-U and Triple-L configurations, some parts of the stair may overlap in the Top/Plan preview, making it difficult to select and edit the intended corner parameters. Before clicking the red areas to set corner parameters for these configurations, select whether the preview displays the Upper part of stair or Lower part of stair.

● For fixed angle winder stair configurations, click the stair winder to set the winder parameters. The Winder Parameters dialog box opens. Specify the number of treads for the winder section of the stair, and select whether the winder tread depths should match the tread depths for the straight parts of the stair. If maintaining a constant tread depth is desired, the minimum winder tread depth may need to be adjusted to prevent errors.

Stair geometry errors

The Geometry tab allows values to be locked, which forces other parameters to recalculate while maintaining appropriate calculated values for the stair. Occasionally, an invalid entry is attempted, which generates an error due to other locked values or to minimum/maximum restrictions.

When this occurs, an Error Correction dialog box opens, describing the reason for the error and offering several options to correct the problem. Select one of the options from the list and click OK to return to the stair parameters.

In the event that no successful correction options are available, an alert dialog box opens instead, to notify you of the error and offer several possible options to avoid it.

● The total rise calculation is based on multiplying the number of risers by the riser height, and therefore cannot be edited without changing one of the values. Similarly, the number of risers or riser height cannot be edited when the total rise is locked.

● The total rise of the stair and the stair length (or sweep angle, for circular stairs) impact other values such as tread depth, riser height, and the number of risers. When the length/sweep angle is locked, it may become impossible to obtain valid entries for the other parameters. Since the stair length or sweep angle is a multiple of the tread depth, one cannot be edited when the other is locked.

● Restrictions defined in the Min/Max Settings may prevent the parameter change. Options in the Error Correction dialog box may allow the restrictions to be slightly loosened, or even completely disabled, so that the stair can be created (this applies especially during the design phase when experimenting with parameter values).

● Winders may be pushed into the straight sections of the stair if one of the Side values changes drastically, resulting in potential calculation errors at the stair corners. The number and range of winders at the corners, or the corner style at the stair’s inner corners, may require modification.

Parameter to be edited	Locked	Unlocked	Resolution
Total rise	Riser Height	Num. of Risers	Change the riser height or the total rise and number of risers as suggested, or return to previous values
Total rise	Num. of Risers	Riser Height	Modify the riser height, or the riser height and the number of risers as suggested, or return to previous values
Total rise	Riser Height and Num. of Risers	N/A	Change the riser height and/or the number of risers as suggested, or return to previous values
Riser height	Total rise	N/A	Modify the total rise, or the riser height and number of risers as suggested, or return to previous values
Number of risers	Total rise	N/A	Change the total rise, or the riser height/step length, or the riser height and number of risers as suggested, or return to previous values

Parameter to be edited	Locked	Resolution
Total rise	Length or Sweep Angle	Change the number of risers and step length, or unlock the length/sweep angle as suggested, or return to previous values
Tread depth	Length or Sweep Angle	Modify the length/sweep angle, and/or change the number of risers and the tread depth as suggested, or return to previous values
Length or Sweep Angle	Tread Depth	Change the tread depth, and/or the number of risers, or change the risers and length/sweep angle as suggested, or return to previous values