1.对您遇到的问题的简要解释。
2.一个最小的代码示例。如果您发现了错误，这有助于我们重现并修复它。
3.背景。你为什么需要这样做？我们可能知道更好的方法来实现您的目标。
4.您正在使用的Cesium版本，您的操作系统和浏览器。
Can you explain a bit more about what you’re trying to do?
Are you asking how to make particles fall, and then hit the ground to stop and bounce? If so, I think there’s no easy way to do it with the built in features in CesiumJS. This is a good reference on the particle system:
https://cesium.com/docs/tutorials/particle-systems-more-effects/
You can potentially get the height of the terrain and make the particle stop/disappear at that spot, but if you’re thinking like snow particles that would roll down a hill, you’d need a full physics engine for that.