Tag: ar

Did you follow the blog post series on setting up Spectator View for HoloLens? The following issues frequently occurred when testing Spectator View. To make your life easier, make sure you check these troubleshooting tips & tricks:

HoloLens Sharing Offset

Between your two HoloLenses, there can be some offset in the placing of the holograms. In one HoloLens, you can for example position your hologram directly on the table; on the second HoloLens, it’s one meter next to the table.

In the final part of the HoloLens Spectator View series, I’ll add the final tweak to my sample project and show you what kind of photos the Compositor saves on your PC. Getting to this point has taken a lot more work than expected (+ a lot more blog posts, too!), but the journey was worth it! You can finally get great photos and videos of the mixed reality experience on HoloLens.

Script Execution Order

Sending the updates didn’t work right away, so I searched for other changes that the sample does differently from my app that might be responsible. One such case was the Script Execution Order.

In Unity, the order in which scripts are initialized is arbitrary. When debugging, I found an issue that an instance of a class wasn’t available yet when a script wanted to access it.

To make Spectator View work in our own HoloLens project, we actually have to understand how it’s working, what it is doing and how it is related to the HoloLens Sharing Experience. Turns out that there is a lot to do in our app (including transmitting custom messages) to prepare it for the full Spectator View experience!

Synchronizing Objects: Anchor & SceneManager

The Spectator View is based on the Sharing experience of the HoloToolkit, but it contains its own “fork” of the code. Instead of us having to manually decide & code which objects and interactions to send via network messages (as in the normal Sharing use case), the fork of the Spectator View transmits some data by default to our DSLR-mounted HoloLens.

However, it’s important to understand that if you use Spectator View, you also need to integrate most of the Sharing code. Essentially, a lot of code is duplicated between the two frameworks, with only slight differences in order to give the DSLR-mounted HoloLens a special role, plus the PC running Unity also needs to connect in order to correctly render the scene.

In the previous part, we’ve re-compiled Spectator View using the latest HoloToolkit sources. At the time of writing, this resulted in a compile error, as the HoloToolkit for Unity has seen a breaking change since Spectator View was released.

In this part, we’ll first fix the Spectator View code, and then set it up correctly in our own Unity scene. Then, we’ll need to check several other things: how to launch the Sharing Service, adding Internet Connectivity and the Holographic Camera prefab.

Fixing the Spectator View Code

From the two choices at the end of part 4, of course, we go with the adventurous road to fix the code 🙂

Turns out that the AddSurfaceObject()  method from the base class SpatialMappingSource  was changed. Instead of directly creating a Surface Object from a mesh, this process was now split up into two parts. There is one method to create the surface object, and another one to add it.