Material grass "construction", how to know when it's finished?

I use the material based grass system a lot and after starting the level it takes between 30 seconds and one minute until all the grass has built up near the player, so you would want to hide the level behind a loading screen until that’s finished.
But how can I know when the building or “construction” of the grass has finished?
Just using a one minute delay to show the loading screen would be a really bad way of doing this since the time the grass needs to built up will vary depending on the hardware, so on PCs with really old hardware it might take up to 2 or 3 minutes.

On a semi-related note, I saw grass buildup time increase DRASTICALLY after switching to 4.9, before it was almost instant.

As for your question, I believe the LandscapeProxy class has something to the tune of GrassFinishedBuilding() which you could query.

I am still using 4.8 :rolleyes:

I would like to only use blueprint. The LandscapeProxy Actor has nothing exposed to BP unfortunately.

'fraid there is nothing you can do then other than delay the loading screen artificially and hope for the best.