Collisions problems


I read your tutorial on vehicle pawn placement:

You propose to place a surface (cube) under the vehicle at launch to prevent it from falling if the terrain tile is not yet loaded below.

This is a constraint if we want to place our vehicle anywhere without having to prepare a safe collision zone in advance on the ground.

Is there an event from cesium that I could capture to inform me that the terrain (and its collisions) is loaded under my vehicle, to start the game after this loading?

I also noticed areas of invisible collisions on the ground sometimes (example an invisible wall on a more or less flat surface). Do you plan to improve this?

Hi @Gregory_S,

Due to the way that the plugin works, this collision issue doesn’t really have an easy solution. Tiles may not be loaded if they aren’t currently visible to the camera, and if the tile is not loaded then there is no collision from the tile in that area. I can think of a few things that might help in your situation, though.

  • You could try disabling Frustrum Culling on the tileset. This will make it take longer to load in the tileset, but may help avoid holes.

  • You could also try using a LineTrace downwards from the vehicle, and wait until the LineTrace finds something below the vehicle before enabling physics/starting the game.

  • A more complicated solution could be to add a secondary camera to your vehicle blueprint that looks down below/behind the vehicle. Now that the plugin supports multiple frustrums for tile loading, this may help ensure that the tiles below the vehicle are loaded more quickly. You’d likely still want to wait and cast a ray under the vehicle to make sure it’s loaded before allowing movement.

As for your second question, I’d love some more information about that issue. Are there specific locations/tilesets where you are noticing this problem? If you can provide steps to reproduce this, we can investigate further.