To Create an Interference Condition in a Space

Use this procedure to create a stair interference area in a space. When you add an interference condition between a stair and a space, a box is cut out around the stair based on the specified headroom height and side clearance.

1. Create a stair that intersects with a space.
2. Double-click the stair to open the Properties palette.
3. Click the Design tab, expand Advanced, and expand Interference.
   

4. Set the size of the interference condition:

   If you want to…	Then…
   specify the height above the treads for the interference condition	enter a value for Headroom height.
   specify the left and right side clearances for the interference condition for straight and multi-landing stairs	enter values for Left and Right Clearance.
   specify the inside and outside clearances for the interference condition for spiral and U-shaped stairs	enter values for Inside and Outside Clearance.

5. Click in the drawing, not on the stair, to remove the selection.
6. Select the space to intersect, and click Space tabModify panelInterference Condition drop-downAdd.
7. Select the stair, and press Enter.
   Note: Changing the Interference values of the stair changes the size of the intersection with the space.