I have found Laser beam pathway with reflective mirrors - and I would like to run the example there:

Unfortunately, this is an example from some years ago, and I use Blender 2.92; so when I click Bake, and then click Play as recommended, I get this:


I guess those massive balls in the screenshot should be small particles? In any case, they seem to be not selectable with the mouse...

So I found how can I change the size of particles? - but that question is even older, and I have no "size" under Physics.

So, how can I control the size of the particles in that example in Blender 2.92?

  • 1
    $\begingroup$ Those are Billboard particles, and are not renderable in modern version of Blender as far as I know, so even if you managed to changed their size I don't think It would help you much $\endgroup$ Nov 11, 2021 at 11:46
  • $\begingroup$ Thanks @DuarteFarrajotaRamos - never heard of Billboard particles before, but it makes sense ... Feel free to post this as an answer, I'll accept it! $\endgroup$
    – sdbbs
    Nov 11, 2021 at 11:51

1 Answer 1


Well...you can fake it...like this:

Turn gravity off, insert an emitter with just one vertex, insert some planes with collision and you get:

enter image description here

I am using a sphere as object here and give it some emission color.

Blend file:

With some HDRI and Bloom turned on:

enter image description here

  • 3
    $\begingroup$ I'll avoid the bins in the Bahnhof from now on. $\endgroup$
    – AndreKR
    Nov 11, 2021 at 19:55
  • $\begingroup$ Thanks, appreciate the workaround and the example .blend file! $\endgroup$
    – sdbbs
    Nov 12, 2021 at 12:17
  • $\begingroup$ glad i could help. $\endgroup$
    – Chris
    Nov 12, 2021 at 12:21

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