Add new "Linear 3D Curves" option in the Curves panel in the render
properties. This renders curves as linear segments rather than smooth
curves, for faster render time at the cost of accuracy.
On NVIDIA Blackwell GPUs, this can give a 6x speedup compared to smooth
curves, due to hardware acceleration. On NVIDIA Ada there is still
a 3x speedup, and CPU and other GPU backends will also render this
faster.
A difference with smooth curves is that these have end caps, as this
was simpler to implement and they are usually helpful anyway.
In the future this functionality will also be used to properly support
the CURVE_TYPE_POLY on the new curves object.
Pull Request: https://projects.blender.org/blender/blender/pulls/139735
6487395fa5