Please do not use the ten year old OptiX API for new developments. You should really try learning the OptiX 7 API instead because that API is more modern, explicit and always faster.
The sutil library is only there to make the OptiX SDK examples source code smaller.
I would not recommend using it in own applications which aren’t just experiments inside the OptiX SDK example framework.
Please read these threads about sutil which explain that the OptiX SDK examples are using hardcoded paths to their local folders and how to avoid that and why it’s unnecessary in own application frameworks:
https://forums.developer.nvidia.com/search?q=sutil%20%23visualization%3Aoptix
Links to OptiX 7 example repositories which are not using the sutil library can be found here:
https://forums.developer.nvidia.com/t/optix-7-2-release/156619