If your CAD models file format is not supperted then you can read about converting CAD models in this tutorial.
The converison to polygon mesh usually creates lots of polygons. If you want to create a low-poly mesh read this tutorial.
After creating your low-poly mesh this tutorial will show you how to convert it to a photorealistic gLTF file.
See this introduction page for step-by-step description how to use the VR application made by the libraries of ApertusVR.