IRR Map commit to file

[Macker]

I'm trying to render out a prepass for an irradiance map and I have it set to multiframe incremental, every 5th frame and have chosen a suitable path for it to save to. it seems to be calculating just fine but the file doesn't appear to be getting any larger; it stays at 1KB. Is this normal? I assume it is saving to RAM and will commit the irradiance map to the file when the prepass is complete?

If this isn't the case; why isn't it saving?! I am desperately short of options on this animation and have zero time to complete it.

[Macker]

Well shit. It didn't commit the irradiance map to the file, and now I have an animation without GI. Useless.

[Macker]

So there are two seperate save file buttons. What's that about?

[Svetlozar Draganov]

Where do you see the Save File buttons ?

There is a Save Button next to IM Mode drop-down meny, and there is a possibility to Auto-Save IM on render end.
The Save button is used if you already have calculated IM in RAM and you want to save it into the HardDrive.
AutoSave option is suitable when you are calculating IM for animation - and it guarantees that IM will be saved after each frame.