Ive been testing and it does not seem that while the doppel center is active, the "things" that they are made out of are neither doppels, nor are they counted as ships, nor units for the matter. I just want to know if its possible to get the dimensions of these things.
I believe they are counted as Particulate. Though, this is simply for the fact that hitting 'clear particles' destroys them.
Doppels are formed from particles, and so "Clear Particles" will destroy the particles, though not the Core.
I believe that the particle over the Doppel "bridge" is held fixed relative to it, so that it is exposed by nearby explosions. To this end, you might be able to use GetParticlesInRadius (with 0 range) around the coordinates of the "bridge" (found with GetAllUnitsInRange and checking if the type is "Doppel"). This would give you the particle which is help over the "bridge".
Combine this particle with GetAllConnectedParticles to get the entire Doppel. The "bridge" may eventually be able to be interrogated with GetScriptVar to find the properties you seek without needing to pick through the particle list.
Actually, if you click 'Clear Particles' several times, it will destroy the core.
Yes, the "bridge" takes damage while the particle above it is damaged or missing, and will repair or replace it.
I use "bridge" to distinguish it from the PRPL Core.