问题
I am working on an very awesome iOS project. And i decided to use sceneKit as main Framework. I got an issue :
How to update the node's SCNGeometrySource, when i apply an animation on it ?
回答1:
That is the expected behavior. When you move a node, it does not change the point data for the attached geometry object. The same is true for transforms.
Instead, the point data in the geometry (and the geometry source) is always relative to the geometry itself.
When the scene is rendered, the node's position and transform (and that of it's parent node) is used to create a single transformation matrix who transforms the positions and normals of the geometry from the "model coordinate space" into the "view coordinate space" and projects it into the screen1.
1: That's a slight simplification but there is no need to be as technical as OpenGL when describing how this transformation works. If you really want to read about all the steps involved, "clip space", "perspective division", and "normalized device space" are some keywords you can search for.
来源：https://stackoverflow.com/questions/29533199/scenekit-how-to-update-scngeometrysource