Scanning large 3D environments

[michael-martinez]

I am encountering limitations while trying to scan a large area.

1) I am the following crash on drawAnchorGeometry(_:):

Is there something to reset when reaching large amounts of meshes?

2) Is the app intended to be used only for small areas?

When scanning a zone, the app seems to look close on a departure zone but does not expand after. I can also see it also in the repo README's video, it scans close to the guitar then "stops".

[beatTheSystem42]

Yeah, go ahead and give the README another look, and also check out my stack post: https://stackoverflow.com/a/71257170/5135949

This project shows you a way, not the best way, to scan what's inside of an area. Limiting your scan to an area is just a cool thing to be able to do. There are many cases where you'd just want to scan an object and not the entire environment. The inBox value is what determines if the vertex is inside your box, think of it like cropping.

That specific crash there, is because the size of the 'mesh.inBox' list has exceeded the limitations of Metal's setVertexBytes (4KB). -> https://developer.apple.com/documentation/metal/mtlrendercommandencoder/1515846-setvertexbytes

The solution is creating an MTLBuffer for that data, and using 'setVertexBuffer' instead of 'setVertexBytes.'

The app will probably crash also due to memory issues when you try to check if each vertex is inside that box with a large scan. There's a better way to do that for sure, but this just serves as an example of what you can do with native iOS. Feel free to toss out any ideas, or for your large scan project, remove the 'inBox' check entirely.

[beatTheSystem42]

@michael-martinez Also, thanks for checking out the repo. Good to see some interest in this thing.

[michael-martinez]

Thanks a lot ; I removed the box limitation and it works fine.

Related question: Does it make sense to also tweak the kMaxBuffersInFlight (to improve performance) and kMaxAnchorInstanceCount (is it only used for vizualization or limiting data also?) parameters?

[beatTheSystem42]

for sure, check this guide out too if you wanna learn a little more: https://developer.apple.com/documentation/metal/resource_synchronization/synchronizing_cpu_and_gpu_work

[mightyG]

Thanks a lot ; I removed the box limitation and it works fine.

Related question: Does it make sense to also tweak the kMaxBuffersInFlight (to improve performance) and kMaxAnchorInstanceCount (is it only used for vizualization or limiting data also?) parameters?

Can you share your approach to removing the box limitation?

[michael-martinez]

As far as I can remember I just commented out the related condition in the counting logic here

See:

if mesh.inBox[fv] == 1 { // comment this condition
    c += 1
}

[RookiePyl]

As far as I can remember I just commented out the related condition in the counting logic here

See:

if mesh.inBox[fv] == 1 { // comment this condition
    c += 1
}

First，thanks. After comment, only part of the area can be scanned. Am I missing something? look forward to your reply.

[jaswant-iotric]

I removed the box check, didnt get the crash but getting trailing edge effect on the frames that are outside of the camera's field of view. Weird. Saw the same issue on one more repo.