Partially rendered env in MineRLObtainDiamondDense-v0

NeurIPS 2019 : MineRL Competition
#1

I’ve just witnessed my agent interacting in an environment which looked partially rendered, ie large pieces appeared as transparent:

This is in MineRLObtainDiamondDense-v0. I am using minerl==0.2.7.

mc_1.log output around these times:

[10:51:00] [Client thread/INFO]: [CHAT] §l804...
[10:51:00] [Client thread/INFO]: [CHAT] §l803...
[10:51:00] [Client thread/ERROR]: Null returned as 'hitResult', this shouldn't happen!
[10:51:00] [Client thread/INFO]: [CHAT] §l802...
[10:51:01] [Client thread/INFO]: [CHAT] §l801...
[10:51:01] [Client thread/INFO]: [CHAT] §l800...

I don’t see anything else suspicious in this log file. The following episodes seem to be running correctly.

#2

Just happened again, seems to be related with large bodies of water.

#3

My wild guess is this has something to do with rendering of chunks and/or world-generator generating chunks. Similar things happen if you travel too fast to one direction (you reach “edge of the world”, but it will appear eventually). Not sure why previously rendered chunks would disappear like that.