Assuming this isn't for a specific mission that requires Panoplies and you're just using the terrain rules: nothing in the rules stops you designating anything your want wherever you want as a Panoply. Those crates, Panoply. That wall of a building with guns modelled on it Panoply. That dumpster with wisps of smoke, Panoply. From a gameplay POV you probably want to be more judicious than that though. If you're talking about items specified in Missions, then you can do either. Usually it's a choice between allowing balanced access or deliberately creating asymmetric access.
Just for completeness this is what HVTs say: "• The players must deploy their HVT models a minimum of 4 inches outside of any Deployment Zones. Moreover, the players cannot place their HVT models either on top of or inside of any Scenery Item or Building, always deploying it in an accessible location on the table" The rules for placing Objectives do not include similar language. So you can place them either on top of or inside of any Scenery Item or Building.
placing objectives on upper levels of tables where you're utilizing multiple levels increases the value of skills such as superjump and climbing plus. Be reasonable but absolutely do place mission objectives on different levels and/or inside accessible buildings. ...maybe don't put the center console for Acquisition on the top of your central four story Armortek Office building, but placing one or more of the consoles for Safe Area on the roof of a single story building
I generally prefer to place objectives on top of buildings instead of inside of them, although I will also make minor edits to building locations if an objective would otherwise won't fit because it would partially overlap the structure. I have a relatively strong bias against the use of building interiors, so for me it's an easy choice to place them on top instead.
Most of the times, I believe, people try to place the consoles or scenario targets outside the buildings, in the plain terrain, but if is not possible, sometimes it is harder move one piece sceno to accomodate the items, so if the piece is accesible, I usually do a roll to choose the level where to place it, if not, them in the top of the building and "play".
As do I, after playing against ISS several times in a row with Kuang Shi order batteries basically untouchable in the DZ :P.
