SceneKit – Clone a node recursively

Question

I am trying to clone all nodes (including their material) recursively. I want to change certain material properties in the cloned nodes without impacting the original node(materials).

This is what I have so far, but it does not seem to be working. Any change made on the new nodes is still reflected on the original nodes.

SCNNode *newRoot = [self.root clone];

[newRoot enumerateHierarchyUsingBlock:^(SCNNode * _Nonnull node, BOOL * _Nonnull stop) {
    SCNNode *oldNode = [self.root childNodeWithName:node.name recursively:YES];
    node.geometry = [oldNode.geometry copy];
    node.geometry.materials = [oldNode.geometry.materials copy];
}];

Answer 1

Try this code:

#import "GameViewController.h"

@implementation GameViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    
    SCNView *sceneView = (SCNView *)self.view;
    SCNScene *scene = [SCNScene sceneNamed:@"art.scnassets/ship.scn"];
    sceneView.scene = scene;
    sceneView.allowsCameraControl = YES;
    sceneView.autoenablesDefaultLighting = YES;
    
    SCNMaterial *material = [SCNMaterial material];
    material.lightingModelName = SCNLightingModelPhysicallyBased;
    material.diffuse.contents = [NSColor redColor];
    
    SCNNode *ship = [scene.rootNode childNodeWithName:@"ship" 
                                          recursively:YES].childNodes[0];
    
    SCNNode *shipCopy = [ship clone];
    shipCopy.position = SCNVector3Make(10, 0, 0);
    
    SCNGeometry *geometryCopy = (SCNGeometry *)[ship.geometry copy];
    shipCopy.geometry = geometryCopy;
    [shipCopy.geometry replaceMaterialAtIndex:0 withMaterial:material];
    [scene.rootNode addChildNode:shipCopy];
}
@end