Need advice on method of creating "hole" in 2D object while retaining the ability to edit...

[casey.outdoorobsessions]

Above is a photo of a work-in-progress landscape design I'm working on. I need help on creating the best method of handling the colored sections, a paver pool deck and the pool itself. Since landscape design is always subject to change, I created both objects as splines (joined with standard lines in appropriate areas like the steps). I needed to retain the ability to move curves around, which as far as I know is best done via a spline. 

However, I simultaneously need three other things:

• A continuously-available ability to find the area of each object...
• Coherence between the two objects (keep the two lines creating the border as separate objects that are "tied together" such that moving one line moves the other)...
• The pool subtracted from the pool deck...
  • In other words, the pool acting as it's own object, yet also acting as a "hole" in the area of the pool deck; the pool deck area should not include the pool itself (for area calculation and design purposes)...

So I need to be able to edit the pool and the pool deck separately, yet keep the border between the pool and pool deck aligned. Otherwise, If I need to edit the shape of the pool, I then need to edit the inner edge of the pool deck to realign the two while keeping them separate in terms of area calculation.

These conditions are possible if I do one the following (but I wonder if there's a much easier way):

1. Convert each object (pool and pool deck) to a polyline...
2. Convert each object to a region...
3. Subtract the pool from the pool deck...
   1. Which allows me to find the area of the pool and the pool deck...
4. Then undo everything in order to get back to an editable spline if changes are required...

-OR-

1. Use BOUNDARY w/ island detection, select the pool deck...
2. Make each object either a region or polyline (tends to be a region as AutoCAD says a polyline cannot be created)...
3. Subtract pool from pool deck...

Now they are quasi-separate objects for which area can be found, but as regions/polylines the curves are not easily editable...

Any advice for a noob on this? Thanks!

[pendean]

There is no such miracle object type in AutoCAD: only the workarounds you appear to be familiar with today.

[Kent1Cooper]

Make the fill-in Hatch patterns again, but this time as Associative Hatches.  That will tie them to their perimeter bounding objects, so when you edit the shape of those, the Hatches will adjust accordingly.  You can just pick on a Hatch pattern and see its Area in the Properties palette.

But I confess I'm not quite sure what you mean by:

• Coherence between the two objects (keep the two lines creating the border as separate objects that are "tied together" such that moving one line moves the other)...

Is that about a double boundary between pool and deck [the image isn't quite clear about it], that should remain in two pieces paralleling each other?  If so, that's a separate problem....