Jan 07 2021 11:55 PM
Jan 11 2021 12:15 PM
Hello there! HoloLens is a mobile device that does a -lot- of computing really fast, and we've paid a lot of attention to keeping the device cool. Overheating can still happen in certain scenarios though, just like any phone will also do, so lets walk through a few things here first!
First off, does the HoloLens overheat during normal usage outside of the application, or is this specific to HoloAnatomy? I haven't worked with HoloAnatomy before, so I'm uncertain what the performance characteristics of it are. HoloAnatomy could be pushing the device to its limits or may even be poorly optimized, and this would likely heat up the device during extended sessions. Given what I've seen in medical MR visualizations, I'd guess this is the most likely case.
If your device overheats quickly during light usage like outside of an application in the OS itself, your device could have an issue.
For occasions where you do expect to be running a heavy or poorly optimized application for longer periods of time, reducing room temperature or storing HoloLens devices in a fridge is something I've definitely seen done.
If it's your own application that you're having trouble with, paying more attention to optimization can help a -lot-! Follow our best practices for performance, and make sure you're at 60 frames per second. Any performance gains after that can reduce power consumption and heat generation, and is absolutely worth doing!
Jan 13 2021 09:16 AM
Could you elaborate a little more? I'm uncertain what you mean when you say it didn't work.
Could you also say a little more about your exercise app? Have you experienced overheating with that as well, or are you worried about something else like the device falling off?
Jan 13 2021 03:57 PM - edited Jan 13 2021 04:02 PM
my app will be expected to progress lecture and practice about exercise for 1~2hours. But when it run more than 1 hour, overheating error is occurred at hololens2. It's occurred not only to apps that I made, but also apps that download at MS stores like 'HoloAnatomy'. And it occurred at other hololens too.
It's place is an office. And in most situations, it is used in suggested environment temperature.
App start ->
in 0~60 minutes -> Cool
50~70 minutes -> warm
60~90 minutes -> critical -> shutdown
Jan 14 2021 05:00 PM
Okay! Since you do have your own app, you can work on this by optimizing it. For HoloAnatomy though, you'll need to bring this problem up to them.
Peeking at HoloAnatomy, I see their framerate changes around from scene to scene. Some scenes are 30-40 FPS, and some are ~50. I know people that would be aghast in horror, this is not a good framerate at all. This could easily be why the device heats up over long sessions. Don't settle for anything less than 60 FPS, and for good temperature control you'll need to do even better than that!
Now, their CPU utilization is not bad, I see a lot of headroom there! So this means they're GPU bound. It's not surprising, medical visualizations tend to be complicated and HoloAnatomy is no exception. They've got a lot of geometry filling a lot of the screen. My recommendations to their team would likely be to optimize their shaders, simplify their geometry, and perhaps do a bit more culling of covered meshes.
One big problem with heat is that it creates a feedback loop! Hot hardware runs slower, and slower applications work harder, which generates more heat.
Since you're familiar with the Developer Portal, this is a good page to keep your eye on! Watch CPU, Power, GPU, and Frame rate. Check that box that says 'Display frame rate', and consider it a bug if you're ever less than 60. If you're using Unity, take advantage of their profiler, it's awesome! And of course, we've got some advice about performance on the docs, for multiple different environments.
Your ultimate goal here is to bring GPU and CPU usage both below 100%. That should reduce power usage, and you'll get a cooler device :)
Hope that's helpful! :)