I'm moving a particle system along a Path3d via PathFollow to simulate an iterating electric beam of sorts. To make the beam stop when hitting pobstacles, I've attached an Area3d+collider to the particle system, so that if there's a collision with environment or player, the PathFollow3d node gets reset, i.e. the particle system + collider is sent back to its starting position.

While this works in principle, the beam will sometimes penetrate the environment to hit the player behind. This happens reliably at certain spots, though I don't really see any common features (hit angle etc).

So far, I've checked the collision shapes (OK), and i've played around with the Area3d collider size (also no luck).
Has anybody other ideas for troubleshooting?

Here's a video for clarification:

I found the culprit. The collision shape was generated from a scaled down mesh3d. I thought that generating a collision mesh sibling from a scaled mesh gives a collision shape with size 1, but turns out the scale is inherited from the mesh3d, which makes collision checks wonky if the scale is not 1. Manually adding multiple collision shapes works now.
I still wonder if there is no way to freeze transformations though (resetting them to 1 without losing the effects). This would make a lot of things easier.

    quickben
    So I tried to fix this by rescaling the mesh through the import menu. While this results in a trimesh collision sibling with scale 1, the beams still go through the mesh :/
    So I guess I'm back at square one but as a workaround, ticking "backface collision" under the wall trimesh sibling CollsionShape options the Inspector seems to do the trick for the most part. sadly it doesn't.