Difference between final render and viewport render

[Arcturus]

I´m learning about light transport in luxcore und have found the following problem: if i render in viewport, my image looks very good, just as i wish. But the normal rendering ("F12") looks different, especially light rays.

Viewport:


Standard render:


I´m using Blender 2.82 und Luxcore 2.3 beta 2.

[B.Y.O.B.]

I couldn't find the source of the problem yet.
The only thing that seems suspicious to me is that some of the objects have negative scales. When I apply the scale on these objects, the viewport render looks like the final render (so both show the problem of the missing light beams).

However, I couldn't really find a problem with the volume setup that would explain the missing beams.

[B.Y.O.B.]

Ah, got it: After applying the negative scale, it is necessary to recalculate the normals.

[Arcturus]

I´m very thankfull, this option i have to remember.