I had this same issue and it turned out that the normals of the obstruction's faces were not being calculated correctly. Once I corrected their calculation, the faces obstructed the objects behind them as one would expect.
Question
When dealing with particles in three.js and using Additive blending I find that the resulting particle system is visible even when there is an object, or objects for that matter, between it and the camera.
Is there a way to make sure that the particles stop being visible when there is an object obstructing them?
Solution
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