Hello,

The difference in thermal performance you're observing is likely related to OEM platform optimizations.

As AR is a newer use case in the mobile market, thus many devices have not been optimized to capture camera frames at 30-60 fps, process those frames, and then render them at the same (or higher) frame rate. iOS tends to be the exception as our experience has found that Apple device camera pipelines are highly optimized and thermally efficient. Platforms are being optimized for VR. For example: Daydream, GearVR. But VR experiences do not rely upon the camera pipeline to be running - unlike AR.

Vuforia attempts to deal with Android device fragmentation by providing the ability to apply performance modes that regulate the camera capture resolution and frame rate:

https://library.vuforia.com/sites/default/api/java/classcom_1_1vuforia_1_1CameraDevice_1_1MODE.html

https://library.vuforia.com/sites/default/api/unity/classVuforia_1_1CameraDevice.html#af6c196d8948b774c4d147cf9eab1a900

The settings will vary from device to device (values depend on several dimensions of device capabilities), but may help you to better mitigate the thermal issues you're observing.

Thanks.

I am having the same issue with all android phones I test my app on. I am doing minimal Update calls and mainly relying on touch events to trigger any other events. Is there a different scanning method to find targets on android vs iOS?

Hello sobo,

I did a quick search for that specific device and there seem to be a number of reports of it having heating issues, especially in relation to 4K video capture and AR camera use. If you have access to a different Android device, I would recommend building to that device instead and seeing if the heating issue is still present.

Thanks.

Hi there,

I'm using Unity 5.6.0p3 and also get a serious heating problem on my Android Device (Sony xperia z5, but also on another deivce, I don't remember which model).

I load my models from a Server (AssetBundles) and even if I don't load anything (the scene is empty!) after a few min my device gets very hot.

And there is not much I do in other Update calls so the problem can't be the code.

I also deploy my app for iOS and there I don't have problems at all. Also when I load a model and track a marker it runs so much smoother than on Android.

Any ideas? I forced the framerate already to 30fps and there is one directional light. But as I said, there isn't a model in my scene anyway.

Any ideas? Thanks!

Thank you so much.

The 'Every Second V Blank' option renders a frame for every other screen refresh, so, given that the screen should referesh at 60 herz, your app will render at ~30 FPS.

Note that you can also control the frame rate via this API:

Application.targetFrameRate

http://docs.unity3d.com/ScriptReference/Application-targetFrameRate.html

On the heating side, it is hard to tell how much could be the exact impact of a reduced frame rate on the device heating, but usually rendering at 30 FPS should result in better heating profiles, i.e. it is quite possible that your App could run much longer before getting into heating your device (compared to 60 fps).

Also, a 30 fps rendering could also save some battery life, compared to a 60 fps setup.

Hi AlessandroB

I have updated my unity version to 5.2.3, kept only directional light and using vertex Lit Shaders. Now getting some better results with regard to heating issue in mobile. There's no much heat in first few minutes. But it radically increases in between 5 to 10 mins. I'm playing around with the other settings too. Hope to reduce the heating issue less than this.

By the way, may I know the difference between 'Don't Sync' and 'Every second V Blank' settings in Quality? Because, when Dont Sync is selected the FPS is 50 to 60 and for Every second V Blank is only 30. Does this affect the process or the heating Issue?

If anything else to be tried in customizing can be added.

Thanks

Jeeva

Thanks a lot AlessandroB

You are really a good samaritan!!! :)  I will try these tips too.

Your replies and tips help a lot and increase my confidence...

-----

Jeeva

"...There's a bit improvement. But still having the heating issue...."

Some additional tips:

- if you have Point Lights in your scene, try replacing them with Directional Lights if possible (unless you have strict requirements that impose the use of Point Lights); Directional Lighting is much cheaper than Point Lighting so it can bring a significant advantage

- consider using shaders that are very cheap to render; for example, the VertexLit shader behaves similar to a standard diffuse shader but it is a lot cheaper to render

"....I changed the rendering mode to Forward, But while zooming, or moving the camera out of the target Image, I am getting WhiteScreen which hides eth..."

mmm... this sounds like a known issue that used to affect Unity 5.0.x and Vuforia 5, which was resolved with Unity 5.1.1 and newer versions;

I would recommend upgrading your Unity version to at least Unity 5.1.4, or even better to Unity 5.2 (5.2.4 or newer) or 5.3 (5.3.1 or newer).

also, note that Unity 5.2.x (5.2.1 and newer) introduces some significant performance improvement over previous versions, specifically on Android.

thanks AlessandroB for the reply... I tried to use those optimization techniques. There's a bit improvement. But still having the heating issue.

I changed the rendering mode to Forward, But while zooming, or moving the camera out of the target Image, I am getting WhiteScreen which hides eth.

You can also find a useful and very comprehensive guide to optmize graphics performance here:

http://docs.unity3d.com/Manual/OptimizingGraphicsPerformance.html

by following the suggestions there, you could achieve better rendering performances and reduced CPU and GPU usage (thus, potentially less heating).

Also, you mentioned using Deferred Rendering instead of Forward Rendering; that could cause some significant overhead to your rendering pipeline and might be one of the cause of the overheating and reduced frame rate.

Recently I tried a C# script for finding out the number of frames per seconds (FPS) while the app is running.

It is rougly 20 to 25 FPS only. Just dont know what else makes the mobile heating.

Waiting for some help still..

Hi @ganeshb,

thanks for the reply. I tried, heating is less comparitively. But still having the problem.

Hi,

Can you try with simple Image target sample on S6 and see if the over-heating still occurs.