I tried out the scene and it seems like the hang problem comes from the
Forbid Holes setting in the
Cesium World Terrain. I’m still investigating the problem, but my educated guess is that the setting requires the tileset to request more detailed tiles to fill the current empty tiles. This setting is typically useful for real time performance where if we encounter an empty tile, we typically render the nearest parent tile that can be renderable in this frame, and download those needed tiles in the background for subsequent frame. However, when the capturing video mode is on (when we click the render button and not when preview in the viewport), the tileset will wait for all tiles to finish downloading before rendering, so if more tiles are needed, it will wait for a long time and maybe forever, which leads to the freeze problem.
Can you please try to uncheck the
Forbid Holes setting in the Cesium World Terrain and see if it resolves the problem? After the setting is unchecked, you may still see the slowness of the video capturing mode because of the blocking call above, but it won’t be hang forever. After everything is finished, the final video shouldn’t have that problem. Increasing
Maximum Screen Space Error setting to a higher number for example like 20, instead of 4 can also helps rendering it faster, since less tiles are needed to download. Also I see the
Loading Descendant Limit is set to be more than 500, but it isn’t needed for capturing video since that value is automatically tuned to 10000. Please let me know if it solves the issue. Below is the setting I currently have at the moment: