20000 separate objects is definitely going to cause a slowdown on the CPU. Do you need all the polygons to be contained by a separate object? Your performance would drastically improve if you used one OTF object that contained all the polygons.
You can add any 3D object underneath another node by specifying the parent when you add it. For example, to add an OTF object under a node called
root, use the following code:
Code:
otf = viz.endlayer(parent=root)