This is a set of scripts for rendering 3D shapes in Blender. To use them, make sure you have installed Blender 2.80 and you can run the demo by typing
blender --background --python demo.py
Before rendering a scene, a very important step is to set up the default rendering devices in the user preferences (e.g., which GPU to use). You only need to save the user preferences once, then the script should detect the GPU on the computer and use them for rendering in the future. To set up the rendering devices, open the blender, go to Edit > Preferences > System, then in the Cycles Render Devices select your preferred devices for rendering (e.g., select CUDA and check every GPUs and CPUs on your computer). After setting up the devices, click the Save Preference on bottom left. If you don't to set up the preference once, the script may ignore the GPU and render the scene using only CPU.