Give us a modifier that instance geometry from another object and allow it to be modified by the other modifiers in the stack

EDIT: This is actually possible to do right now with the array modifier! Change the array to 1 and target the object as a start or end cap. Easy enough!

Sometimes you want to add geometry to an object, but still want this geometry to be it's own editable object. It would be great to have a modifier that allow you to do that, just to get the geometry in the modifier stack and have it be affected by the modifiers below it.

Simple example: I'm making a leather belt and I want to add stitches to it. The belt is flat so I model the stitch flat. But now I want to curve the belt with a curve modifiers so I have 2 options:

• I merge the stitches geometry with the belt geometry in a destructive way
• I add the same curve modifier to the stitches

Both solution have their problems. Merging both objects is obviously destructive, no point explaining further why this is bad. Adding the same modifier on the stitches means that you have to change it every time you change the modifier on the belt, and what if you have several modifiers after the curve ? Then to make it parametric again you have to add drivers to the stitches modifiers that copy values from the belt modifiers and things get complicated and there is a lot of setup involved.

We need a way to allow for extra geometry to come along the 'modifier stack ride' without actually merging vertices. Just let the geometry intersect and do nothing except create an instance of this geometry that will be affected by the rest of the modifier stack.

So my idea is a boolean modifier union that doesn't alter geometry but just add object B to object A, and have object B be altered by the modifiers on object A stack that comes after in the stack.

So basically this means taking the boolean modifier code (or making a new modifier), modify some lines it so it doesn't alter geometry but instead simply add instanced geometry, and make that instanced geometry affected by the modifiers that comes after it.

Does that make sense? I feel like this would be super useful based for 'parametric modeling' workflows.