Cesium camera follow does not track

CesiumJS
1

Good afternoon.
I'm using Cesium 1.19 and we are noticing when we track our spacecraft using the camera follow feature (we select the object, and select the camera to follow). The camera will follow the object for a set time and then lose the orientation (flips between the spacecraft and earth wildly) and return to the user set zoom and orientation. Any ideas on how we can correct this. We have used our same setup on the latest release and the same issue occurs.

Thanks.

2

Hi there,

Is there a particular reason you are still using 1.19? We’ve updated a lot of the camera tracking code since then, it might be the best solution to update. Otherwise, could you provide a code snippet of how you are tracking the spacecraft?

Thanks,

Gabby

3

Good afternoon Gabby,

Thanks for the replay. I recently used the latest and greatest cesium 1.41, we use the natural EarthII because we operate in the offline mode but it appears that when we use 1.41 with natural EarthII only half of the globe is displayed with the other half in blue. To see if the latest Cesium would resolve the camera tracking we placed it back online and noticed the same error occurred. I have attached our code for your review (also included is our natural earth files) see Apps/HSatviewer.js for the actual code​
Cesium_debug.zip

​. We do not setup any camera functions we just use the default that Cesium provides.

Thanks you for the help

Marcel

4

Good morning Gabby,

Just wanted to touch base and see if the development team required anymore information from us regard the camera track in our configuration.

Thanks

Marcel

5

Hi there,

The version of Cesium should factor into ability to use Natural Earth II offline if all the files are present. However, let us know if all the files are there and you are still having issues.

Taking a look now, it looks like you were using viewer.trackedEntity. What I think is happening is that Cesium has different modes for fast-moving vs slow-moving objects, (see this line in EntityView.js)You can try adjusting that time delta to a value that suits your needs.

Thanks,

Gabby

6

Gabby,

Thanks for having a look, we use the same files for natural EarthII that work under Cesium 1.16, below is a link from cesium website that shows the image I see when using the natural earth files under the latest version. I updated the time delta to 1.3 that seemed to stop most of the “object flips (tracks really nicely, before when we did spacecraft slews the camera track would go all over the place)” but i’m still getting them especially around the poles, do you have any suggestion what a satellite time delta should be set too?. Again, thank you very much for you support. Let us know if you need anymore info for debug, our natural earth files were in that link that contained our program.

https://cesiumjs.org/Cesium/Build/Apps/CesiumViewer/?tmsImageryUrl=%2F%2Fcesiumjs.org%2Ftilesets%2Fimagery%2FNaturalEarthII&view=-19.839690550324814%2C-22.710981432418027%2C27004628.813310094%2C360%2C-89.81090813433661%2C0

Marcel

7

Good evening Gabby,

Just checking in to see if you and the team had anymore ideas you would like us to try?, we have adjusted the delta time and are still seeing the camera losing track. Is there a way we can just disable this feature.

Thanks

Marcel