Can I make a mirror on a moving actor?

Hi, I have seen a few tutorials on making mirrors, best of which was the ones using planar reflection. However, that as is doesn’t suit the task for the two following reasons:

a. I need to make a planar mirror with a circular and not a rectangular shape ( I can’t simply cover the periphery around the mirror to make it look circular for gameplay reasons).

b. I want to put the mirror on a moving actor.

A circular motorbike mirror would be a great approximation of what I am trying to do.


Neither of the points you mentioned are an obstacle to planar reflections.

I’d strongly suggest you actually try things out first hand, it’s very easy to watch a tutorial and convince yourself that you “know” how it works. But until you’ve used it you’re just making a guess based on someone elses experience.

Planar reflections are not an object that is visible in the world, they have a debug plane that is shown by default in the editor but this is not visible in game. The reflections produced get added to the reflection environment and are simply used for any glossy surface in the affected area. The shape makes no difference.

There also isn’t any reason why you can’t use a planar reflection on a moving object.

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Interesting, I’ll look further into it.

Now that I’ve read your reply I understood that is a volume of ‘concern’ for the gpu to look for materials with applicable params.
It wasn’t clear neither from quick videos, nor from the documents, as all used examples I saw were literally ‘planar’ reflection.

Anyway, great answer, thanks.


I’m going to guess ray-tracing/lumen reflections wouldn’t be an adeqete solution then? Planar reflections are certainly an option, but the GlobalClipPlane imposes a bare minimum 15% perf penalty. While that’s absolutely fine if you’ve budgeted for it, it’s certainly not nothing.

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