An externally rigid to semi-rigid wearable computer case for housing various computer components may include two different types of external sides: ventilated-sides and a non-ventilated side. In some embodiments, the wearable computer case may have four to five ventilated-sides. The ventilated-sides and the non-ventilated side together may form an enclosure for housing the various computer components. The ventilated-sides may include ventilation-holes. The ventilation-holes in a given ventilated-side may provide for a ratio of void space to non-void space (in terms of external surface area) that may be substantially from and including 0.6 to 0.4. Some embodiments may also provide for hot swap battery pack(s) that may be external to the wearable computer case and that may provide at least some electrical power to the various computer components housed within the wearable computer case. The wearable computer case and/or the hot swap battery pack(s) may be for VR/AR/MR use.