n any case, here are some numbers showing what the performance is currently like on a regular PS4 at 900p resolution, without MSAA, with the hair covering a big chunk of the screen. So for the long-haired asset, which contains about 10’000 strands and a total of 240’000 points, the physics currently take around 4.7ms and the rendering takes around 4.5 ms. The short-haired asset, which contains about 15’000 strands and a total of 75’000 points, the physics instead take around 0.4ms and rendering about 1.9ms.
The main reason for the long render times are currently that our GPU utilization is very low, something we are currently investigating different ways to improve. Keep in mind again that this is with all strands rendered and simulated every frame. In comparison some of the alternative hair simulation system only simulate about 1% of all hair strands. Early experiments show that we can get a 5x performance boost by simulating only 1/10th of all strands and interpolating the results.