When I render with IrradianceMap from file mode , can I turn off the GI Secondary engine?

[will_will]

I use IM+LC save the irradiance vrmap file.
Does Irradiance map file contains all the GI data ? If it does, may I turn off the Secondary engin ?

[hermit.crab]

No, it contains only the IM data. You can always pre-calculate both IM and LC and load them afterward.

[will_will]

Yes , it'seems BOTH IM and LC are <from file> mode required .

In my test, at first I use a white light and saved IM file ( IM single frame mode + LC single frame mode), and then changed IM to <from file> mode .
after then I created a red light , render agian , red bounced lights in box's back can be seen in processing , but no red GI in final result in IM <from file> and LC <single frame> mode.
there is no difference between images with IM <from file> , LC <single frame> and image rendered with IM <from file> , no secondary engine.

that why I got this strange question, I thought IM file contains all GI data , thats wrong. Maybe the LC single frame mode calculated data not joined final image, I am not sure.

[hermit.crab]

there is no difference between images with IM <from file> , LC <single frame> and image rendered with IM <from file> , no secondary engine.

This depends on the scene. If you close the volume, so that there are actual bounces (which are taken care of by the secondary Gi engine), you'll see a difference.

[will_will]

This depends on the scene. If you close the volume, so that there are actual bounces (which are taken care of by the secondary Gi engine), you'll see a difference.

I made another scene for testing, can't see red yet, maybe I missed something.
Could you please take a look to my scene. (3dsmax2023)
vr1test.zip

the irradiancemap is rendered without red lights and sphere self-illumination material

[hermit.crab]

It seems you were right all along. The LC is indeed saved within the IM. And if you wish to have the LC separately, it must be exported prior to IM. This used to be documented in the old documentation (I'll post it as soon as I find it).

[will_will]

So it will help us save lots of render time.
Thank you for confirm this .