Examples of using mulitres mesh?

[eddyod]

Is there any example code for using the multi resolution mesh creation with scripting?

[william-silversmith]

Hi Edward,

I would just follow along with the code in the CLI module. You need to do the initial mesh forging tasks as "sharded" then you need to call sharded mesh merge.

Let me know if you need more help!

[eddyod]

Something like this?

tasks = tc.create_meshing_tasks(layer_path, mip=0, sharded=True)
tq.insert(tasks)
tq.execute()

tasks = tc.create_sharded_multires_mesh_tasks(layer_path, num_lod=2)
tq.insert(tasks)    
tq.execute()

[william-silversmith]

That looks like it works!

[eddyod]

Must we use the sharded=True parameter? When I use this, I get:
python3.10/site-packages/cloudvolume/lib.py:297: RuntimeWarning: overflow encountered in scalar multiply
return reduce(operator.mul, self)

And then this file is not created: mesh_mip_0_err_40/0.shard

I'm using int8 as the data type by the way.

Thanks!

[william-silversmith]

That's a pretty odd error. That makes me think the bounding box is being manipulated incorrectly for some reason. What are the dimensions of your dataset?

If you're working with a reasonably small dataset, then (I forgot this existed for a sec) you can use the unsharded multi-res. Omit the sharded flag and use this function, create_unsharded_multires_mesh_tasks, to create the merging tasks.

https://github.com/seung-lab/igneous/blob/master/igneous/task_creation/mesh.py#L449-L513

[eddyod]

Thanks, I'm having better luck with the unsharded process and it appears to be working!