Failed to find /AirSim/Blueprints/BP_PIPCamera

[plusk01]

System: Ubuntu 18.04 / 64 GB RAM / Intel i9 / GTX 1060 6 GB / SSD
Versions: UE4.22 / ROS Melodic / AirSim master
Environment: Blocks (ran from UE4 Editor)
Settings: default

After fast-forwarding the last ~50 commits (since about a week ago), running ./clean.sh and then ./setup.bash and ./build.sh again, I try and open Blocks with UE4.22.3:

$ ./Engine/Binaries/Linux/UE4Editor $HOME/dev/AirSim/Unreal/Environments/Blocks/Blocks.uproject

I see the following error:

[plusk01]

It's probably related to the fact that the Blocks environment was saved in UE4.24 and I am using UE4.22:

[plusk01]

UE4 was able to see a BP_PIPCamera.uasset from another project (saved in UE4.22.3). So it seems very likely that I'm seeing these errors (resulting in a crash) because the BP_PIPCamera.uasset was saved in UE4.24 in #2518.

@madratman if AirSim is targeting >= 4.22 this asset should be saved there and newer versions can convert as needed. (Similarly Blocks.uproject should be saved with 4.22 and instructions should continue to suggest to users to convert in place).

If useful, I can save/commit BP_PIPCamera.uasset from my (Linux) UE4.24.3 if @saihv can tell me exactly which flags were changed. My guess is that Capture Every Frame was disabled so that Always Persist Rendering State could be enabled:

[saihv]

@plusk01 Thanks for finding the cause! You are right, the BP should have been saved with 4.22 for compatibility purposes, I missed that.

As to the content in the blueprint, the workflow is to

1. Disable Capture Every Frame.
2. Enable Always Persist Rendering State.
3. Re-enable Capture Every Frame.

Please feel free to submit a PR if you already have BP_PIPCamera saved under 4.22.