Parametric Design

I'm confused by some of what you wrote in your post, such as trying to adjust the artwork for the thickness of the plywood being laser cut. Are you cutting 2D shapes through the plywood or actually doing something in 3D where you are both cutting shapes and varying the depth of what is being cut? I'm not aware of cutting depth being something that is adjustable with a laser. Do you have an image or two of what is being cut out of the plywood?

I work quite a bit with a standard 4' X 8' routing table that uses traditional metal routing bits. Most of what I cut is just 2D elements, such as letters cut out of aluminum or colored acrylic. Anything 3D has to be done within the specialized routing software we use (EnRoute). The thickness of the router bit used has to be factored into the artwork, be it 1/8" or 1/4". Lasers cut a much thinner line, so not as much offset is needed.

If I had a bunch of parts I needed to rout, but decided I was going to use a 1/8" bit rather than a 1/4" bit I could make a new copy the objects I was going to cut and use the path offset command to create a new tool path closer to the original letter forms. I'd "expand" the effect and save it as a .DXF file to feed into Enroute. Of course, EnRoute does this function as well.

For shapes that interlock with precise corners. I'm not sure if there's any way to quickly adjust an entire group of objects. Some tricks with the path offset command or apply outlines to the shapes and expanding those outlines can quickly create shapes that either fit together more tightly or loosely.

If you're increasing or decreasing the size of multiple objects by the same amount, double-click on the Scale tool to open the Scale dialog. You can change the size uniformly or non-uniformly by entering the percentage you want to increase or decrease.

Create a symbol for the notch.  Later if you need to make the notch for  wider you need only adjust the symbol once.

An issue you will likely encounter is the position would shift when updating the symbol, because the bounding box of the notch changed dimension. You can overcome this by putting a rectangle filled with none larger than your shape and preferably centered into your original symbol. this way the fill of none will always be the largest time in your symbol.

No. Why not simply invest money in a decent CAD/ drafting program where this is commonplace?

Mylenium