Lasers are a pain
Added 2025-02-02 10:04:27 +0000 UTCWhen Jollypops says she likes lasers, you make lasers.
That said; lasers are a pain in Iray. I like to make them using emissives: There are a couple of good beam props on the market that you can buy, but you can make your own using a simple cylinder primitive, scaled long and thin, or two (or more) plane primitives aligned together in a star shape.
Because even slight lighting changes can affect the whole of the render, it becomes impossible to composite multiple scenes together if the lighting wasn't exactly the same for each one.
The best solution I've found is to try and set the scene out so that every single beam is accounted for right at the start. Then, unparent the beams from their owners and save them as a group that can be re-loaded into every subsequent scene, simply for the purposes of maintaining the lighting.
