Instance is undefined inside the combinedGeometry worker

I’m plotting almost 4,000 billboards and rectangles. The billboards are using canvas for the images, and the rectangles are using toDataURL to display images. Everything renders fine, but once in a while I get the following error when panning the map:

An error occurred while rendering. Rendering has stopped.
TypeError: instance is undefined
More details about the error is shown in the attached snapshot.

Question 1: I’m trying to figure out the source of the issue. What does it means when I get this kind of error message from the combinedGeometry worker?
Question 2 : Has anybody experience this issue?
Question 3: How can I captured errors of the kind “Rendering has stopped” so I can continue using the map?. When I get this kind of error the map is completely disabled. I tried by listening to the scene’s pre and post render events to make sure the viewer.useDefaultRenderLoop = true, but it never reaches my event listeners.

Using Firefox 38.0.1
Windows 7
Cesium version 1.9



Try using the unminified version of Cesium. It has more useful debug info.

The pre and postRender events will not help, the preRender is called before the crash and the crash is preventing the postRender to occur. Your best bet for debugging this if the unminified version is not able to provide you with enough information to immediately fix the problem would be to set a conditional breakpoints in the scene.render method.