Change of Obstacle shape on Unity

[HarukiKozukapenguin]

@yun-long
Goal
Current agile_flight simulator's obstacle is only sphere, and I would like to change this obstacle's shape now.

My basic understanding of agile_flight
By ZMQ(https://zguide.zeromq.org/docs/chapter1/), especially zmqpp, the flightmare send obstacle' information to Unity
(
https://github.com/uzh-rpg/flightmare/blob/9707f45b9ac3bf8c5dcde0ccacd6628b1dbabfba/flightlib/src/bridges/unity_bridge.cpp#L89
https://github.com/uzh-rpg/flightmare/blob/9707f45b9ac3bf8c5dcde0ccacd6628b1dbabfba/flightlib/src/bridges/unity_bridge.cpp#L136
)
Basic information of obstacle information is written under
$project_path/flightmare/flightpy/configs/vision and I found that prefab is limited to "rpg_box01"

Quesrtion
Can we make an obstacle shape except for a sphere?
What can be taken in "prefab" except "rpg_box01"?