BackSide not shown at certain camera angle?

[andreasplesch]

Investigating, I found material.side = THREE.TwoPassDoubleSide.

With that option the BackSide is correctly shown. Why are two passes needed but only sometimes ?

https://github.com/mrdoob/three.js/pull/21967 and

Build (130 - 131) Performance dropped by 50% due to new texture processing with DOUBLESIDE material

[ - YouTube] Good evening, I decided today to do a performance test between build versions 129 and 131. At the stage of loading the scene, it slows down because the recording is in progress and the browser without a cache, all data is loaded from scratch. I have uploaded one of the locations this is a forest for 50 mobs. In my engine, it is provided that all objects that do not enter the camera are automatically removed from the scene, and when the camera is directed at them, they …

has some background. DoubleSide is complicated with transparent objects.