Son of a Brick!

Sometimes both vacuuform or donnacona board scenic brick are impractical. The set for the Munchkins in the Muppets Wizard of Oz, for example, has a vast background of miniature yellow bricks. This would be difficult to achieve with CNC sheets, as the grout lines are so fine, it would be difficult to maintain them when applying the scenic sandy slop. Without such a protective layer, the bricks would also get easily trashed by the unit (no offence).
Another solution is the 'doll house' brick method. This too is quite affordable; It requires good Scenics.
You can set up a cad file, similar to the one used for the donnakona CNC sheets, with your custom brick size,  and have them cut out on paint mask by the local sign shop. You are then left with a 'web' of grout.
The Scenic Painters can apply this web to the raw flats, then apply a thin layer of spantex/sand/paint/glue mix. Once its slightly set, you can quite easily pull off the web, leaving the 'mini-bricks' in place on the flats.
Once they have dried, they are very workable and hold up tho the wear and tear of shooting.

Another Brick In The Wall

Okay, I'll admit, if I was designing a set for, say, Spongebob Squarepants I may deliberately choose the look of vacuform brick. It does have its place. And indeed it used to be the affordabe and sometimes more practical option over scenic brick. Scenic brick used to require the laborous individual pinning of each brick plus a half inch of heavy grout fill. The walls were a wild-wall nightmare.
But it says 'SET'. You cannot hide the look of cheapo vacuform brick. And Ive never seen a successful attempt at wrapping it around corners.
Nowadays we have a new method available. If you are lucky enough to have a good CNC company that you work with, I have fount that this is now the best way to go. You can quite quickly set up a 4x8 cad brick file, and you can even help the scenic painters by setting up the file with a slightly irregular grid and slightly roughened cut lines. The CNC machines can just take the grout lines down 3/16in, and its very efficient, quick and quite affordable.
The scenics can then just brush on a slurry of sandy slop and the bricks need minimal sculpting this way.
The walls remain relatively light for wilding.

Stairway To Grid

I have had more heated discussions over stair shootoffs than any other set elements in the history of my career.
For some reason, mant people cannot understand that you cannot build a stair on stage without either an L in the staircase or a landing with a backing flat and a ceiling flat.
My experience in filmmaking has taught me that if you give the filmmakers an action toy like a staircase, they WILL use it, and they WILL want to pont the camera up the stairs, and they will see the grid.
A model is a useful tool to explain the shootoff problems that stairs present. I am a big fan of models, however, time does not always permit. The next best thing is a sketchup model, its worth throwing one together if you are having trouble convincing the powers that be.

Wheelchairs

Whenever I read 'wheelchair' in a script my rolling-light goes on. Usually the wheelchair will be in action on camera. As a result, often I find myself drafting up a set with a practical ramp.
Depending on the Production Designer, this can bring up some tricky set design issues. Not all PD's are well rehearsed in architectural standards, as they come from all walks of life. Some were Interior Designers, some were Graphic Artists etc. The good PD's are aware of their deficiencies, after all, who knows about everything? They hire people who can fill in the gaps for them, thereby building a solid team. They listen to their set designers, whose job it is to look the data up, and explain to the PD that his/her design must be reconfigured due to the wheelchair ramp requiring a lineal length of 38 feet.
The wheelchair ramp grade can be found in the stairs & ramps chart in any Graphic Standards book.

Set Extensions

I love VFX. I dont love noticing it though. If I notice a VFX as one, it usually means it was poorly executed and therefore looks fake.
Set Designers are often asked to draw the lower half or portion of a set, which VFX will later add an extension to in Post. There is often a huge disconnect between Art & Post, often its a vast canyon of non communication.
Have you ever watched a show that looked like so much money went into it but all the VFX were terrible? Often there is an overload of work that wasn't budgeted for that ends up being dumped on the VFX dept after everyone's all gone home and the mony's spent. This is why often the VFX end up crappy.
Good communication at the set design level between the departments is key to a happy ending in Post.
If you know the set will have an extension, you can help the VFX artists by designing the set with a deliberate cutter line at the extension line, like a cornice, or a conduit, or a brick pattern etc.

Practically Speaking

The question of practicality is ultimately a question of money. In an ideal world, all the kitchen cabinets would be practical on a studio set, giving the Actors and Directors the most freedom for their creative process.
"The Budget" usually prohibits this freedom. The practical cabinets are too expensive to build, not only in materials and man power, but also consider the extra set dressing and product placement.
Who decides which cabinets should therefore be designed as practical? As a Set Designer you really have no place to make that call. You can ask the question, however, chances are that you are asking weeks before the action will actually play. In Film, this is like trying to plan something months in advance. Its difficult for the creative heads to commit to such a decision so early on. The Designer has to talk to the Director, the Director has to talk to the Writer....
As a Set Designer I would add a series of notes "Note: Practical cabinets per Designer.".
This places the very budget-conscious Construction Coordinator on the demand line. Also, it affords time for the decision to be made while the plans can still go out.

Cheating

Cheating is a term set designers use when they design sets that are seperate shooting entities, yet are filmed and portrayed as the same location. There are several reasons a set designer may cheat a set. A studio set may only have the stage space to build a lower level of a house, requiring a separate set to be built that would play as the upper level. Usually in this case, the cheat is in the stairwell; it gets built twice. Sometimes the film gets shot, only to need additional scenes to be shot at a location that can no longer be used. If the scene was a set that has been torn down, a record of the construction plans, paint colours, lighting and set dressing is crucial to recreate some kind of continuity. Sometimes a location is perfect, except for a particular scripted area, which needs to be cheated.
Cheating is fun! Its like a big game of 'spot-the-difference'.

The Changing of the Guard

"It is ideas and attitudes that change the world. We need a completely new attitude towards our mother the earth and all that lives on her generous bosom. Today we use our powers to despoil and destroy; we must be shown how to use them to cherish and preserve. Our future depends upon those who see and can help others to see. The older generations, with few exceptions, are blind. Hope lies with the young; but even they too must put short term selfish aims aside and work for the future." ~ J. G. Bennett