What aspect of a building does not affect the lightning vulnerability?

The factor of internal materials in a building does not significantly influence its vulnerability to lightning strikes. Lightning primarily interacts with the external structure of a building, including how it's shaped, designed, and situated in relation to its environment.

The shape and design of a building can impact how lightning is attracted to it and can influence the pathway the lightning may take when it strikes. For instance, pointed or sharp features may draw lightning more effectively than flat surfaces.

Location and height play critical roles as well, since taller structures are statistically more likely to be struck by lightning. Buildings positioned in open areas or in proximity to other tall structures may also experience an increased risk.

While the surrounding landscape can affect the strike probability by creating conduits for lightning, such as trees or hills that are taller than the building itself, the materials used within the building, like drywall or insulation, do not substantially change how lightning interacts with the external structure. Therefore, internal materials do not contribute to the building's vulnerability in a meaningful way compared to the other factors listed.