The optixRaycasting example is using some native CUDA kernels to generate the primary rays and do the shading.
The OptiX SDK 7.1.0 examples compile for SM 6.0 (Pascal) by default to avoid having deprecation warning for SM 5.0 (Maxwell) when using CUDA 11.
Maybe not all places have been set to SM 5.0 in your CMake scripts to work on Maxwell.
https://forums.developer.nvidia.com/t/a-supported-nvidia-gpu-could-not-be-found/144180/6
https://forums.developer.nvidia.com/t/optix-7-1-issue-with-running-samples-on-a-maxwell-card/140118/2
I haven’t checked out the differences in compute capabilities of sm_50-sm_75 yet.
That is mostly irrelevant. You can simply use SM 5.0 as target for the PTX compilation to be able to run your OptiX application on all supported GPU architectures.
https://forums.developer.nvidia.com/t/support-multiple-compute-capabilities/126076/2
We needed the Optix 7.1, and I saw that then R450 is a requirement. R450 existed only for Ubuntu and Win10, but converting the examples CMake file to Ubuntu was painful. So I went for now with this debugging platform with Win10 + R450. If anyone would get the 7.1 examples working with Ubuntu I would be interested to hear about it.
Which Ubuntu, CMake, GCC and CUDA version have you been using?
The OptiX SDK examples should work out-of-the-box without changing the CMakeLists.txt files on any supported OS.
If that is no the case, you would need to add some more information what exactly you changed and why.