When the emitter is outside the system and rotated & scaled, the velocity (VectorDirection3D, TargetDirection3D) isn't calculated properly. Attached a test case for this which contains cylinder "pipes" with different position/scale/rotation and the particles should be moving inside them.

I believe problem is in QQuick3DParticleEmitter::emitParticle the way m_velocity should take into account also the scaling.