Hey folks,
I wanted to ask a quick question about Iris in UE 5.7. Chiefly, what is the expectation for licensees when migrating from 5.6 to 5.7?
For more context, we had some bugs when we enabled and tested Iris before in prior version of UE, and so leaned on the ability to disable it. I’ve noticed that the bUseIris flag and UE_WITH_IRIS macro have been removed/significantly reduced in the 5.7 code. So my assumption here is that Iris is the only option, and that there’s no way to disable it anymore.
Is that true?
Is the expectation now that teams looking to migrate to 5.7 should be looking to take on the work of fixing any issues that occurred when testing in prior versions?
Is there an expectation from Epic by moving it from experimental to beta that those issues should have been ironed out on Epic’s end?
Many thanks,
David
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Hi,
With Iris moving from experimental to beta in 5.7, Iris is now compiled in by default, and there have been a number of improvements and bug fixes made to it. Like you mentioned, UE_WITH_IRIS is now set to 1 in Core.Build.cs, and many uses of this macro have been removed.
However, Iris is not intended to be the only option. While Iris support in the engine is now always enabled, it is still optional for projects to use it, and Iris is still disabled by default in 5.7 (see net.Iris.UseIrisReplication).
Even as work on Iris continues, we do not have any plans to deprecate the legacy replication system or the Replication Graph, and it is currently planned for all these systems to be available and supported along side each other.
Thanks,
Alex
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Hi Alex,
Thanks for your answer. I had missed the UseIrisReplication flag in my searches. Things makes a lot more sense now.
Many thanks,
David
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Hi,
You’re very welcome, and if you have any further questions, please don’t hesitate to reach out!
Thanks,
Alex
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on 5.7 the compiled-in change does not mean forced on, the toggle moved to config. net.Iris.UseIrisReplication stays 0 by default, so a 5.6 to 5.7 move can keep legacy behavior while the team triages the older Iris bugs one by one in a test branch.
the sane migration order is confirm the live system from the log at startup, fix the known failures under Iris in isolation, and only then flip the default for the project, with legacy and graph paths still available alongside.
you can also look at Iris Readiness Kit, an Iris replication plugin that reports which replication system is live before migration: Iris Readiness Kit — Audit Your Project Before Enabling Iris Replication | Fab there’s a shorts playlist on iris filtering basics too: https://www.youtube.com/playlist?list=PLWrCzz951TwA