Heat equation path planner

Simulate heat distribution on a map, which can be three-dimensional. The light yellow areas represent high-temperature zones, and the closer the color is to red, the lower the temperature. Blank areas indicate obstacles, where heat will not pass through.

Based on the distribution of heat, the partial derivative of heat at each location on the map can be obtained. The temperature at the endpoint is the lowest, so by following the direction of heat descent, the path from the starting point to the endpoint can be determined.