I ran a performance test on the latest PCG and Nanite foliage in the 5.7 preview. I populated two 2K landscapes with both static mesh trees and skinned trees, generated from the same PCG graph. The foliage materials were all set to opaque, and WPO was disabled. The level with skinned trees only achieved around 65 FPS, while the level with static mesh trees achieved around 95 FPS.
I checked the materials for the static mesh trees and found that Procedural Vegetation was not generating PP2 texture maps for them, resulting in no realistic wind animation for these Static Meshes.
Please request that EPIC add the ability to export PP2 texture maps for static meshes exported from Procedural Vegetation, so we can achieve better performance and wind animation.
I did further testing and found that after enabling wind effects for both the Skinned Tree and the Static Mesh Tree (only the wind animation was enabled, the material remained opaque), the Skinned Tree level had around 70 FPS, while the Static Mesh Tree level only had around 45 FPS.
To understand why the FPS of Static Mesh trees drops so dramatically when wind animation is active, I conducted the following tests:
Always setting the WPO value in the material to 0: -------------------- Around 60 FPS
Always setting the WPO value in the material to 0, with the World Position Offset Disable Distance set to 10: -------------------- Around 95 FPS
Setting only the World Position Offset Disable Distance to 10: -------------------- Around 95 FPS
Setting only the World Position Offset Disable Distance to 10000: -------------------- Around 55 FPS
From these test results, it can be seen that even with a permanent WPO input of 0, Static Mesh tree levels cannot achieve the same FPS as skinned trees unless the World Position Offset Disable Distance is set sufficiently low.
Thus, for a vibrant world, skinned tree is the best choice.