Occupancy grid

[kevin-thankyou-lin]

Thanks for the great project and codebase! Is there a way to get a 3D occupancy grid with which I can do obstacle avoidance trajectory generation?

[JacopoPan]

This is not something currently implemented but I could give it some thought, can you give me a small example of the scenario/output you would like to see? Should the occupancy grid be part of the obs (i.e. do you need it for RL) or could it be an additional entry in info (i.e. you are using the environment simply as a simulation?

[kevin-thankyou-lin]

Gotcha, I was looking more for something like:

Airsim's Voxel grid construction (microsoft/AirSim#3209)

to get the 'ground truth' 3D state of the world. I'd use it as an additional entry in info - specifically, I'd want to use it for ground truth optimal planning.

I think we could use something like this voxelization tool for the .obj files for the sphere, samurai, etc URDFs (http://www.open3d.org/docs/latest/tutorial/Advanced/voxelization.html).

That said, I think I'm good without an occupancy grid at this stage, but thank you for helping!

[JacopoPan]

I should give it some thought. Note that collisions are managed by PyBullet (see the collision queries api) using the collision shapes specified in the .urdf file of each drone/object (these could be simple geometries or .dae/.obj meshes). The ground truth position/orientation of any object in the sim can be retrieved with a call to p.getLinkState(), then (knowing the collision shape/mesh of each object) one could use Open3D's voxelization. I have to look into how to use basic geometries and multiple meshes in a single Voxel grid but I suspect it could result in a significative computational overhead.

[kevin-thankyou-lin]

Sounds good! Yeah, it'd probably result in significant computational overhead.