topic Re: Crash on iOS trying to run .slpk 3D building layer in ArcGIS Maps SDK for Unity Questions

Crash on iOS trying to run .slpk 3D building layer

StarrLong — Tue, 21 May 2024 21:17:19 GMT

We have built a large scale Active Digital Twin of the Port of Corpus Christi that includes base layers and a 3D building layer using .slpk files.

We are using the Unity Maps Plugin.

When we run a 3D building layer / .slpk above 50mb the application crashes instantly on an iOS device (10th generation iPad Pro).

For reference on windows we can run a 500mb + file with no instability of any kind.

I have attached a screenshot of the windows version and the crash logs from TestFlight.

Re: Crash on iOS trying to run .slpk 3D building layer

AShahbaz — Fri, 24 May 2024 22:51:37 GMT

Hi there, a few clarifying questionns:
Does the crash happen with any building scene layer slpk or only this particular one (or only ones that are above 50mb)?

Does this happen if you stream the building scene layer instead of a local slpk?

Are you using the streaming assets folder for copying the slpk to the device? And can you verify that the app finds the file?

I tried to search for the reason of exception information further up in the log (SIGNAL 5 Trace/BPT trap) and it seems like it can be a number of issues (out of index array, accessing null or invalid references, ...).

Re: Crash on iOS trying to run .slpk 3D building layer

StarrLong — Sat, 25 May 2024 20:56:12 GMT

Thank you so much for replying!

We see the error when we try to use any large-ish slpk (60+mb) that works fine on desktop.

Our .slpk is stored locally (in StreamingAssets) but it doesn't seem to matter if it is streamed.

We do not copy the file to local storage. It stays in StreamingAssets (Except on Android, but that isn’t currently one of our target platforms.)

Yes it finds the file.

Re: Crash on iOS trying to run .slpk 3D building layer

AShahbaz — Wed, 29 May 2024 00:15:02 GMT

Thanks for the additional information.
We tested a couple different building scene layers (BSL) on an ipad and did not experience any crashes. We tested both streaming and local data, with the largest slpk being almost 1.5GB.
One thing to keep in mind is that in the process of loading a local file, the slpk is unpacked in the momery, occupying more momory than the file itself. However, this should not have any effect while streaming the data, and with a file size of 60mb, I don't really expect the effect to be significant enough. But you might want to look into how full the memory is without the BSL. For reference, the device we tested on has 8GB of memory.

I would try loading the BSL in an empty project on the ipad to rule out other parts of the project as the cause of the crash. You may also want to test with a completely different BSL.

Are you adding the layer at runtime or in the editor? This is an example of creating and adding a local BSL layer.

var buildingLayer = new Esri.GameEngine.Layers.ArcGISBuildingSceneLayer( Application.streamingAssetPath + $"/{BSL_File_Name}", "Layer Name", 1.0f, true, ""); arcGISMapComponent.View.Map.Layers.Add(buildingLayer);

Re: Crash on iOS trying to run .slpk 3D building layer

StarrLong — Wed, 29 May 2024 14:55:38 GMT

My apologies. I do not think I was clear enough in my description before. We are not using a BSL. Ours is a "3d Object Scene Layer" that we are adding at runtime. You can see this video of it running on windows here: https://www.dropbox.com/scl/fi/57vajbzy5nctqf5of02wk/OPTICS-2024-05-21-15-24-44.mp4?rlkey=bdx0umeofsn6dyzkcwjtprcph&dl=0

Re: Crash on iOS trying to run .slpk 3D building layer

AShahbaz — Wed, 29 May 2024 18:22:33 GMT

We could not reproduce the crash with a 3D object scene layer either. File size ~360mb, placed in StreamingAssets and loaded with the following code:

using Esri.ArcGISMapsSDK.Components; using Esri.GameEngine.Layers; using Esri.GameEngine.Layers.BuildingScene; using Esri.Unity; using System.Collections.Generic; using UnityEngine; public class LoadData : MonoBehaviour { [SerializeField] private ArcGISMapComponent arcGISMapComponent; private ArcGIS3DObjectSceneLayer sceneLayer; private const string fileName = "sandiego.slpk"; private void Awake() { arcGISMapComponent = GetComponent<ArcGISMapComponent>(); } private void Start() { // Make layers: sceneLayer = new Esri.GameEngine.Layers.ArcGIS3DObjectSceneLayer( Application.streamingAssetsPath + $"/{fileName}", "San Diego", 1.0f, true, ""); // Add layers: arcGISMapComponent.View.Map.Layers.Add(sceneLayer); }

Re: Crash on iOS trying to run .slpk 3D building layer

StarrLong — Wed, 29 May 2024 18:29:44 GMT

Would it be possible to get a version of your sample 3D building layer so we could better understand possible differences between the assets?

Re: Crash on iOS trying to run .slpk 3D building layer

StarrLong — Wed, 29 May 2024 18:50:00 GMT

Here is a dropbox link to a section of our 3d building layer that reliably causes the crash (note this is not even the complete file just a section along the main channel): https://www.dropbox.com/scl/fi/9lhwva4qpta21womth7ye/CorpusChristi_BUILDINGS_channel_area.slpk?rlkey=ti89cblo7w467c2qo459o23d4&dl=0

We were also able to get the crash to happen with files we generated from blender (a completely different pipeline). I can send that file as well

Re: Crash on iOS trying to run .slpk 3D building layer

AShahbaz — Thu, 30 May 2024 00:06:30 GMT

We did a test run with your data. Although we didn't get a full-on crash, we did notice missing meshes that are likely related to running out of memory.
It seems like your data has no or very limited level of detail information, which means that even far-away meshes are loaded with great detail. I was able to notice minor changes to the appearance of the ship (close to the aquarium) as the camera moved away, but the geometry remained at a pretty high resolution. I couldn't really notice any changes to the surrounding buildings until they disappeared once the camera was too far. I suspect this is the reason for running out of memory on a mobile device.

You could test this by adding a small extent to the ArcGISMap (map needs to be local) and checking if it still crashes.

If this is in fact the issue, your layer needs to be updated with finer levels of detail and/or less content.

Re: Crash on iOS trying to run .slpk 3D building layer

StarrLong — Thu, 30 May 2024 14:37:30 GMT

This is definitely helping us get closer to a solution I think!

Can you please share a few data points to assist?

1. How are you able to diagnose that there were missing meshes in the file? Is there a tool in ArcGIS Pro for that? Did you read that in an error message somewhere? If so can you point us to some documentation?

2. You mention updating our .slpk with LODs. Can you point us to some documentation on how to do that? My cursory search could only find a mention of it as a feature but not how to use it.

3. While I understand how not having LODs or missing meshes might cause us to run out of memory at runtime I am confused because it feels a little counterintuitive because at initial load won't it actually increase the memory size due to the need to have the multiple assets to support the LODs? For us the crash happens as soon as we load the building layer.

4. You mention above that you were able to run an .slpk that is actually larger than the one that crashes for us. Your San Diego one is 360 mb while the one we sent you is only 204 mb. Am I to understand that if LODs are present the initial load in will be smaller and it will then dynamically stream in the rest of the file therefore preventing running out of memory?

Re: Crash on iOS trying to run .slpk 3D building layer

StarrLong — Thu, 30 May 2024 15:16:14 GMT

Also can you please confirm which iOS device you are running your tests on? We ran our tests on iPad Pros (5th and 6th generations)

Re: Crash on iOS trying to run .slpk 3D building layer

StarrLong — Tue, 04 Jun 2024 15:23:00 GMT

I was wondering if you had been able to review my clarifying questions?

Re: Crash on iOS trying to run .slpk 3D building layer

AShahbaz — Wed, 05 Jun 2024 01:32:31 GMT

Sorry for the late response. Here is some more information

1. How are you able to diagnose that there were missing meshes in the file? Is there a tool in ArcGIS Pro for that? Did you read that in an error message somewhere? If so can you point us to some documentation?

What I meant by that is that in the app, not all meshes or the best textures are rendered. It is not related to the layer itself, but is an artifact that happens when there is not enough memory available to load further goemetry/textures. See below a screen capture. Once we added a (small enough) extent to the map, it loaded the entire geometries withing that extent.

2. You mention updating our .slpk with LODs. Can you point us to some documentation on how to do that? My cursory search could only find a mention of it as a feature but not how to use it.

I used this tool to convert your slpk to a newer i3s version. It added some finer LoDs for the textures, but the geometries still seem unaffected (see screen capture below). The way I test the existence of LoDs is to play the scene in the editor and manually change the "Quality Scaling Factor" under ArcGIS Camera Component and look for changes in the scene.

There is probably a way of integrating the LoD generation in your data creation workflow, but I am not familiar with that. I am sure someone else at Esri could point you to the right process. But in the meantime you could convert your slpk with the above tool and test it within your app to see if there is any improvement. You may want to try the tool with and without the -x option, which provides some optimization but has a big effect on the size of the output slpk. You could also set the "Quality Scaling Factor" in your app to a small value (e.g., 0.1) to see if it has any effect on the crash.

3. While I understand how not having LODs or missing meshes might cause us to run out of memory at runtime I am confused because it feels a little counterintuitive because at initial load won't it actually increase the memory size due to the need to have the multiple assets to support the LODs? For us the crash happens as soon as we load the building layer.

4. You mention above that you were able to run an .slpk that is actually larger than the one that crashes for us. Your San Diego one is 360 mb while the one we sent you is only 204 mb. Am I to understand that if LODs are present the initial load in will be smaller and it will then dynamically stream in the rest of the file therefore preventing running out of memory?

To be clear, I am not sure if adding LoDs will resolve your issue because we haven't been able to reproduce the crash, but since we experienced memory issues with your slpk (as implied by the missing geometries/textures), this could be a place to start.

There are two different ways where memory is used. One is for unpacking the slpk into the memory. And you are right that adding LoDs will likely increase this memory need. The other one is the on-demand loading of the assets based on the location of the camera. Here, lack of LoDs will increase the memory demand since higher-quality geometries and textures will be loaded even for objects far away from the camera. For testing purposes, setting the quality scaling factor to a small value will be helpful in limiting the assets that are being loaded in the first place. Or, as mentioned before, adding an extent to the map could achieve the same. If you still hit the crash with a small extent, we are probably not on the right track.

Also can you please confirm which iOS device you are running your tests on? We ran our tests on iPad Pros (5th and 6th generations)

11-Inch iPad Pro (4th Generation) M2 chip, 8GB ram, 128GB storage, model number mnxd3ll/a. Could you please provide more details on your devices as well?

Re: Crash on iOS trying to run .slpk 3D building layer

StarrLong — Wed, 05 Jun 2024 15:32:35 GMT

Thank you again for the answers!

We are testing primarily on 2 mobile devices (one older, one newer):

iPad Pro 3rd Gen: M1 Chip, 256 GB Storage, 8 GB RAM

iPad Pro 7th Gen: M4 Chip, 1 TB Storage, 16GB RAM

Is there a chance that because we had our slpk in an older version of the is3 format we could be triggering the fatal error?

Re: Crash on iOS trying to run .slpk 3D building layer

AShahbaz — Wed, 05 Jun 2024 19:18:27 GMT

I can't say that for certain, but I doubt that the version per se would cause the error. The plugin supports versions 1.7 and higher (the one you shared was 1.7). It is possible though that the converter does some optimization/fixes along the way.

Trying to better understand the issue it would be interesting to know whether the crash still happens with (a) the updated slpk, (b) a map extent.