Extracting vertices from scenekit

Question

I\'m having a problem with understanding scenekit geometery.

I have the default cube from Blender, and I export as collada (DAE), and can bring it into scenekit....

Answer 1

For someone like me want to extract data of face from SCNGeometryElement.

Notice I only consider primtive type is triangle and index size is 2 or 4.

void extractInfoFromGeoElement(NSString* scenePath){
    NSURL *url = [NSURL fileURLWithPath:scenePath];
    SCNScene *scene = [SCNScene sceneWithURL:url options:nil error:nil];
    SCNGeometry *geo = scene.rootNode.childNodes.firstObject.geometry;
    SCNGeometryElement *elem = geo.geometryElements.firstObject;
    NSInteger componentOfPrimitive = (elem.primitiveType == SCNGeometryPrimitiveTypeTriangles) ? 3 : 0;
    if (!componentOfPrimitive) {//TODO: Code deals with triangle primitive only
        return;
    }
    for (int i=0; i