The low volume rendering seems not to work.

[Derry-Xing]

发生异常: RuntimeError (note: full exception trace is shown but execution is paused at: _run_module_as_main) The size of tensor a (3) must match the size of tensor b (640000) at non-singleton dimension 1

UserWarning: Using slow volume rendering, should only be used for debugging warn("Using slow volume rendering, should only be used for debugging")

out_rgb += light_intensity. * self.background_brightness