>>63854590
Obviously putting a mylar thermal blanket over yourself is going to conduct and start heating up pointlessly. But most of these people building gnome cloaks are trying to create standoff and/or insulation to reduce this conduction. It sort of works when you're innabush, none of it works inside a house or in a clear open field. The early SAS TIC suits created pockets of lofty air around your body to slow thermal conduction into inner layers. Obviously this is flawed from the start since any insulation traps heat in and you will heatcat out if its anything close to hot out.
>Military projects
Mostly glass nanospheres doped to match the emissivity of the surrounding environment and provide scattering. You can see the sticky finish on barracuda that is the epoxy holding these to the fabric. In pic rel you can look at my knee/calf and see the edge of a barracuda net that is stood off of my body. The center of a barracuda will do vastly better and if the thermal imager is >5ft away you are going to more or less melt away into the background
>Issued ponchos
Eh the early TIC suits were basically that but less improvised. UCLANS is basically a gigantic standoff net with sometimes barracuda. Relv eclipse panels are more or less that and work effectively even with limited standoff
>DIY testing
There are some solutions out there with fairly accessible materials and methods but yeah, thermals be difficult