Most of the complex stair examples shown below, was created from images on my favourite stair inspiration website: Stair Porn. Best to check with your network administrator whether the site will be blocked on not.
The first four stair designs will show two pictures each, the first being a Realistic Visual Style representation, and secondly a Rendered Image of the scene.
The fifth staircase was quite challenging for someone working on custom stairs only once every few months, so detailed steps and images will be provided for the creation process.
Stair Challenge #1: Reception Desk Incorporated into Stair Treads
Stair Challenge #2: Concrete Spiral Stair with Center Post
Stair Challenge #3: Compact living storage staircase
Challenge #4: Floating Wood Stair
Challenge #5: National Library of Greece Entrance Stair
* Remember: No in-place families were allowed in this challenge.
The first obstacle to overcome was that one cannot attach a wall's top base to a stair. This can only be done for Roofs, Floors, Ceilings and Walls
A dedicated floor was created to indicate the stair treads. This was done to allow the walls to attach to the tread's (Floor's) bottom.
Sketching out a separate floor per tread would have been a very tedious task, so I opted to create an radial array from the floor tread.
The treads were then aligned to the stair treads' top, to ensure that the elevations are correct. Because an array was created, the floor edges are not aligning to the exact tread positions.
These floor edges were aligned as well.
Because the stair treads were created as floors, the wall's top bases can now easily be attached to the bottom of the treads.
This did take a bit of time to complete, because when one selects a wall and start the Attach Top Base command, the command must be run again each time an attachment needs to take place. Time wise, this process took about a quarter of a beer.
Custom railings were created, using balusters as well as baluster panels.
A few additions were added to the staircase design, including a topography, road, planting, columns, etc. Time wise, this took about 3 quarters of a beer.
Even though the rendered image looks fine to me, the pedantic types out there will shout OVEREXPOSED! Keep in mind that the rendering time was another beer, and by that stage I just accepted the result.