Thermal camouflage is used to confront with infrared (IR) imaging by concealed or misled heat signature of the targets. Most previous conductive thermal camouflage only achieves the equivalent temperature profiles outside the illusion device, and the targets may still be observable from the z-plane imaging. The two-dimensional (2D) illusion thermotics was proposed to add the split thermal illusions inside the illusion device, which advances the thermal camouflage performance. But a drawback remains that the thermal illusions are not separated from the heat source, which only creates distorted heat signatures rather than camouflages the heat source. In this study, we develop the three-dimensional (3D) illusion thermotics with separated thermal illusions to remove the drawback for perfect thermal camouflage performance. Finite-element simulations validate that although the real heat source is located at the bottom center, both symmetric and asymmetric thermal illusions can be generated on the top surface, misleading the number, size, and position information of the real heat source from the z-plane IR imaging and achieving perfect thermal camouflage performance. The 3D illusion thermotics may open avenue for more thermal functionalities with enhanced flexibility at the cost of enhanced complexity.