SCNNode.removeFromParentNode() and rendering loop

Question

i have a question regarding removing SCNNodes I have a function that makes a SCNNodes, when the Node is ready I add it with:

scene.rootNode.addChildNode(node)

then I make a new SCNNode with the function and like to remove the old one and add the new one, unfortunately SCNNode.removeFromParentNode() wont remove the old one:

func cleanUpAndAdd(){
        for node in scene.rootNode.childNodes{
            if node.name == "object" {
                node.removeFromParentNode()
                scene.rootNode.addChildNode(object)
                object.name = "object"
            } else {
                scene.rootNode.addChildNode(object)
                object.name = "object"
            }               
        }            
    }

It just adds and adds and never removes...

What am I missing?

Did you set your SCNViews playing property to true? sceneView.isPlaying = true Otherwise it might look like the object is not remove because the view did not redraw after you remove it. — Kai Engelhardt, Jun 21 '17 at 16:38

score 2 · Answer 1 · answered Jun 22 '17 at 12:21

2

Note that SCNNode.childNodes is a collection (array) and so per Cocoa conventions you should not try to mutate it (SCNNode.addChildNode(_:)) while it's being enumerated. If you do so SceneKit will note generate a runtime exception, but the behaviour is undefined.

answered Jun 22 '17 at 12:21

mnuages

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I removed this part, thank you. I just do the cleanup and add it later. – M. P. Jun 23 '17 at 13:22
If by cleanup you mean `removeFromParentNode`, you shouldn't do that either because it is also mutating the collection. – mnuages Jun 23 '17 at 15:05

score 0 · Answer 2 · answered Jun 21 '17 at 10:16

0

That code is correct, assuming you have set the node name. You didn't show us that part. How about adding "else print node.name"?

answered Jun 21 '17 at 10:16

Hal Mueller

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For clarification I am calling a function with NSNotificationCenter where I create my object and add it to the scene. When the "Notification" function gets called again I create a new object then I make the clean up and add the new one. I think I have to somehow trigger the Rendering Loop each time I make a new object... – M. P. Jun 21 '17 at 11:59

score 0 · Accepted Answer · answered Jun 23 '17 at 13:17

0

So. After hours of troubleshooting I realised that the SCNGeometry I was making contained also the SCNGeometry sources from the previous SCNGeometry.

So the rendering and removing was correct.

answered Jun 23 '17 at 13:17

M. P.

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SCNNode.removeFromParentNode() and rendering loop

3 Answers3