The latest WIP (May 2, 2017) contains an experimental feature called GPU tessellation. This feature is off by default. You can turn this on by checking the “GPU Tessellation” option on Rhino’s OpenGL options page.
What Is GPU Tessellation?
GPU tessellation attempts to move as much surface, polysurface, and extrusion wire drawing as possible on to the graphics card. All breaking down of curvy wires into tiny line segments and thickening of these segments for wire pixel thickness is performed in a series of “shader” programs on the GPU.
Does this work on all computers?
No - we use a feature of OpenGL 4.0 called tessellation shaders to perform the drawing. You must be using a graphics driver that is at least OpenGL 4.0 capable. Fortunately, OpenGL 4.0 appears to be pretty commonly available on many different graphics cards. If your graphics card is not running at or above OpenGL 4.0, then Rhino will draw these wires the same way as it has been drawing them in the past.
Why should I care?
Speed!!! Results will vary quite a bit from card to card, but we have seen huge performance improvements with some cards (most notably nVidia so far). Note that this is only for drawing the wires of polysurfaces and extrusions so if you are using a display mode that doesn’t show these items then you should notice no difference
What can you do to help?
Please turn this feature on and see if everything still “looks” correct. We have seen some problematic cards which produce odd results for wireframe drawing of polysurfaces and extrusions. We think we have this solved, but I want to to with more cards to be sure.
Why is this not on by default?
This is still early work and I don’t want to mess everyone up. We also noticed that this feature is actually performing worse than the old technique on some AMD cards. This is what we are currently investigating because we know the hardware is capable.