如何在不重置SCNNode位置的情况下重置SCNNode的SCNPhysicsBody？

Question

I have a sceneKit app for iOS. I have an SCNPhysicsBody attached to an SCNNode. I set the .physicsBody to nil, make some changes the SCNNode and then set the .physicsBody to a new SCNPhysicsBody or to a copy of the original SCNPhysicsBody. In either case, the SCNNode resets its position to its initial position.

How can I reset the .physicsBody and keep the SCNNode in the same position so it continues on its trajectory?

Answer 1

When your physics affects node position its original position (that was assigned to node position property) stays same, presentation node position is changed. All transformations (rotation/scale/translate) works that way.

So you can do something something like this pseudocode:

// 1. remember position of presentation node
var position = node.presentation.position;
// 2. do some changes on node, physics body, whatever
// 3. restore position (without losing original node position)
your_node.presentation.position = position
// ... or apply presentation position to original position
your_node.position = position