scenekit - zoom in/out to selected node of scene

问题

I have a scene in which a human body is displayed. I want to zoom in to a specific body part when a user taps on it.

I changed the position of the camera to the position of Node but it points not exactly on it.

Also I need to keep the selected part in center of the screen when zoom in.

How can I accomplish zoom in / out?

回答1:

To reposition it in a Z-axis you want to multiply the currents node matrix with the new matrix.

var node = childNode.transform
var translation = SCNMatrix4MakeTranslation(1.0, 1.0, adjustedZValue)
var newTrans = SCNMatrix4Mult(node, translation)
childNode.transform = newTrans

Edit: Had some names mixed up

回答2:

I solved my problem by moving the camera instead of scaling the Model. I got the tap point by Gesture Recognizer and similarly the point of touch.

Now I converted the View-Coordinates to Scene Coordinates

CGPoint p = [gestureRecognize locationInView:scnView];

    NSArray *hitResults = [scnView hitTest:p options:nil];

    SCNVector3 projectedOrigin = [scnView projectPoint:SCNVector3Zero];

    SCNVector3 vector = SCNVector3Make(p.x, p.y, projectedOrigin.z);

    SCNVector3 worldPoint = [scnView unprojectPoint:vector];

and then positioned the Camera to the worldPoint.

回答3:

a bit cleaned up and more "swifty":

let transform = childNode.transform
let adjustedZValue = Float32(3)
let translation = SCNMatrix4MakeTranslation(1.0, 1.0, adjustedZValue)
let newTrans = SCNMatrix4Mult(transform, translation)
childNode.transform = newTrans

来源：https://stackoverflow.com/questions/49870884/scenekit-zoom-in-out-to-selected-node-of-scene

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scenekit