My SceneKit project uses an imported .OBJ file, which contains only one node with a huge image. Image comprises different objects or parts. I need to tap on a foot, or image specific part, and have it highlighted.
This is code to import .obj File
sceneView = SCNView(frame: self.view.frame)
self.view.addSubview(sceneView)
let scene = SCNScene(named: "OBJ.obj")!
print("\(scene.rootNode.childNodes.first?.geometry?.materials.count)")
sceneView.scene = scene
and here I am using tap gesture recognizer
// add a tap gesture recognizer
let doubleTapRecognizer = UITapGestureRecognizer(target: self, action : #selector(self.tapGesture(sender:)));
doubleTapRecognizer.numberOfTapsRequired = 1;
doubleTapRecognizer.numberOfTouchesRequired = 1;
sceneView.addGestureRecognizer(doubleTapRecognizer);
func tapGesture(sender: UITapGestureRecognizer){
let hitResult : SCNHitTestResult
// check what nodes are tapped
let p = sender.location(in: sceneView)
let hitResults = sceneView.hitTest(p, options: nil)
}
I have 3D Model with different parts like left foot right foot and floor needed to be tapped and show different color on them. The problem is that all of these are in single node.
Your SCNHitTestResult will give you the index of the triangle that was tapped. But you'll still have to work out the logic of going from a single triangle to recognizing "that was the left arm".
I think your best bet is to go back to your 3D modeling software and break the object into smaller, logical components.
Related
I can't find a good explanation of what a SCNCamera is and it's purpose. This is Apple's definition:
A set of camera attributes that can be attached to a node to provide a
point of view for displaying the scene.
This definition isn't clear because I set up the scene and added a SCNNode without attaching a SCNCamera to it. The point of view from the device's camera shows the SCNNode at the location I positioned it at with no problem and the scene is displayed fine.
What is the difference between the device's camera and a SCNCamera?
What is the benefit of attaching a SCNCamera to a SCNNode vs not using one?
If I have multiple SCNNodes (all detached no hierarchy amongst each other) does each node need it's own SCNCamera?
If I have multiple SCNNodes in a hierarchy (parent node with child nodes) does each node need it's own SCNCamera or does just the parent node?
lazy var sceneView: ARSCNView = {
let sceneView = ARSCNView()
sceneView.translatesAutoresizingMaskIntoConstraints = false
sceneView.delegate = self
return sceneView
}()
let configuration = ARWorldTrackingConfiguration()
override func viewDidLoad() {
super.viewDidLoad()
// pin sceneView to the view
let material = SCNMaterial()
material.diffuse.contents = UIImage(named: "earth")
let plane = SCNPlane(width: 0.33, height: 0.33)
plane.materials = [material]
plane.firstMaterial?.isDoubleSided = true
let myNode = SCNNode(geometry: plane)
myNode.name = "earth"
myNode.position = SCNVector3(0.0, 0.6, -0.9)
sceneView.scene.rootNode.addChildNode(myNode)
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
sceneView.session.run(configuration, options: [])
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillAppear(animated)
sceneView.session.pause()
sceneView.session.run(configuration, options: [.resetTracking, .removeExistingAnchors])
}
In SceneKit, the SCNCamera represents the point of view from which the user sees a scene. Ray Wenderlich provides a good explanation:
Think back to the analogy of the movie set from Chapter 1: to shoot a
scene, you’d position a camera looking at the scene and the resulting
image of that scene would be from the camera’s perspective.
Scene Kit
works in a similar fashion; the position of the node that contains the
camera determines the point of view from which you view the scene.
You do not need to have a SCNCamera for each node. You should only need to have one camera for each angle that you want to show, or even just one. You can move one camera throughout the scene using its parent's position property.
It looks like you're working with ARKit, which behaves a little differently. When using an ARSCNView, as opposed to a non-AR SCNView, you get the following behvior:
The view automatically renders the live video feed from the device camera as the scene background.
The world coordinate system of the view's SceneKit scene directly responds to the AR world coordinate system established by the session
configuration.
The view automatically moves its SceneKit camera to match the real-world movement of the device.
You do not need to worry as much about the scene's camera in this case, as it is automatically being controlled by the system so that it matches the device's movement for AR.
For more detail, see Apple's documentation on SCNCamera: SCNCamera - SceneKit
I got the answer to my question from within this answer. Basically in ARKit using ARSCNView the camera comes from sceneView.pointOfView but in SceneKit you need to create a camera to get the camera pov (code below).
Getting the camera node
To get the camera node, it depends if you're using SCNKit, ARKit, or other framework. Below are examples for ARKit and SceneKit.
With ARKit, you have ARSCNView to render the 3D objects of an SCNScene overlapping the camera content. You can get the camera node from ARSCNView's pointOfView property:
let cameraNode = sceneView.pointOfView
For SceneKit, you have an SCNView that renders the 3D objects of an SCNScene. You can create camera nodes and position them wherever you want, so you'd do something like:
let scnScene = SCNScene()
// (Configure scnScene here if necessary)
scnView.scene = scnScene
let cameraNode = SCNNode()
cameraNode.camera = SCNCamera()
cameraNode.position = SCNVector3(0, 5, 10) // For example
scnScene.rootNode.addChildNode(cameraNode)
Once a camera node has been setup, you can access the current camera in the same way as ARKit:
let cameraNode = scnView.pointOfView
I am going to detect horizontal and vertical plane in ARKit. After detecting whether it is horizontal or vertical surface, respectively add plane of gray color on detected surface.On tap on detected plane I am going to add 3D object of .scn file.
My code is working fine for placing 3D object (.scn file) on horizontal plane but not working correctly with vertical plane.
3D object (.scn file) for vertical plane like photo frame is facing right in SceneKit editor. So I changed it’s EularAngleY to -0 and it’s facing front now in SceneKit Editor. When I tap on detected vertical plane which is facing to front then also photo frame is facing to right and If I move device facing right and place photo frame then it’s correct.
I want to place 3D object .scn file which should be parallel to plane (If vertical plane is facing front then it should be face front even in .scn file it faces to any direction).That 3D object is not parallel to detected plane.
Have I needed to change rotation also with respect to detected plane’s angle or need to do any changes in .scn file in SceneKit editor? How can I achieve it?
Please check below code on hitting detected vertical plane. Is there anything wrong?
#objc func addObjectToSceneView1(withGestureRecognizer recognizer: UIGestureRecognizer){
let tapLocation = recognizer.location(in: sceneView)
let hitTestResults = sceneView.hitTest(tapLocation, types: .existingPlaneUsingExtent)
guard let hitTestResult = hitTestResults.first, let anchor = hitTestResult.anchor as? ARPlaneAnchor else { return }
let translation = hitTestResult.worldTransform.columns.3
let x = translation.x
let y = translation.y
let z = translation.z
guard let shipScene = SCNScene(named: "art.scnassets/frame/frame.scn"),
let shipNode = shipScene.rootNode.childNode(withName: "frame", recursively: true)
else { return }
shipNode.position = SCNVector3(x,y,z)
sceneView.scene.rootNode.addChildNode(shipNode)
}
.scn file is like below. Is this .scn file correct? Or x should be with frame's depth? Everytime whenever I tap on plane it will show image like this only.
As I mentioned in the answer here, it is better to add an ARAnchor to the ARSession rather than directly adding an SCNNode into the scene graph after doing a hit test. Currently the code you posted doesn't take into account the rotation of the detected plane. For the code to work you would need to determine the normal of the detected plane take the dot product and cross product with the desired orientation of the model calculate the rotation, then apply the rotation. However, the ARSession will do all of that for you. By using ARAnchor(transform: hitTestResult.worldTransform) the rotation is encoded into the anchor. So you will only need to deal with transformations with the models own local coordinate space.
For example:
#objc func addObjectToSceneView1(withGestureRecognizer recognizer: UIGestureRecognizer){
let tapLocation = recognizer.location(in: sceneView)
let hitTestResults = sceneView.hitTest(tapLocation, types: .existingPlaneUsingExtent)
guard let hitTestResult = hitTestResults.first, let anchor = hitTestResult.anchor as? ARPlaneAnchor else { return }
// create anchor and add to session and wait for callback
let anchor = ARAnchor(transform: hitTestResult.worldTransform)
sceneView.session.add(anchor: anchor)
}
Then in your session delegate call back:
func renderer(_ renderer: SCNSceneRenderer, nodeFor anchor: ARAnchor) -> SCNNode? {
if anchor is ARPlaneAnchor {
// node for plane anchor
let anchorNode = SCNNode()
return anchorNode
} else {
// must be node for most recent hit test
guard let frameScene = SCNScene(named: "art.scnassets/frame/frame.scn"),
let frameNode = frameScene.rootNode.childNode(withName: "frame", recursively: true) else { return nil }
return frameNode
}
}
In you're scn file you'll want the model to be located at the origin laying flat without any transforms. This means you'll likely need to nest nodes and position the underlying model relative to a parent empty node.
Here "frame" is the outer node with no transform that is returned from nodeForAnchor and "picture" is rotated to be flat and scaled to the size of the content.
Final result:
I want to create a sample application that allows the user to get information about continents on a globe when they tap on them. In order to do this, I need to figure out the location where a user taps on an SCNSphere object in a scene (SceneKit). I attempted to do it like this:
import UIKit
import SceneKit
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let scene = SCNScene()
/* Lighting and camera added (hidden)*/
let earthNode = SCNSphere(radius: 1)
/* Added styling to the Earth (hidden)*/
earthNode.name = "Earth"
scene.rootNode.addChildNode(earthNode)
let sceneView = self.view as! SCNView
sceneView.scene = scene
sceneView.allowsCameraControl = true
// add a tap gesture recognizer
let tapGesture = UITapGestureRecognizer(target: self, action: #selector(handleTap(_:)))
sceneView.addGestureRecognizer(tapGesture)
}
#objc func handleTap(_ gestureRecognize: UIGestureRecognizer) {
// retrieve the SCNView
let sceneView = self.view as! SCNView
// check what nodes are tapped
let p = gestureRecognize.location(in: scnView)
let hitResults = sceneView.hitTest(p, options: [:])
// check that we clicked on at least one object
if hitResults.count > 0 {
// retrieved the first clicked object
let result: SCNHitTestResult = hitResults[0]
print(result.node.name!)
print("x: \(p.x) y: \(p.y)") // <--- THIS IS WHERE I PRINT THE COORDINATES
}
}
}
When I actually run this code however and click on an area on my sphere, it prints out the coordinates of the tap on the screen instead of where I tapped on the sphere. For example, the coordinates are the same when I tap on the center of the sphere, and when I tap it in the center again after rotating the sphere.
I want to know where on the actual sphere I pressed, not just where I click on the screen. What is the best way that I should go about this problem?
In the hitResult, you can get result.textureCoordinates which tells you the point in your map textures. From this point, you are supposed to know the location of your map as the map should have coordinations which was mapped to textures.
#objc func handleTap(_ gestureRecognize: UIGestureRecognizer) {
// retrieve the SCNView
let sceneView = self.view as! SCNView
// check what nodes are tapped
let p = gestureRecognize.location(in: scnView)
let hitResults = sceneView.hitTest(p, options: [:])
// check that we clicked on at least one object
if hitResults.count > 0 {
// retrieved the first clicked object
let result: SCNHitTestResult = hitResults[0]
print(result.node.name!)
print(result.textureCoordinates(withMappingChannel 0)) // This line is added here.
print("x: \(p.x) y: \(p.y)") // <--- THIS IS WHERE I PRINT THE COORDINATES
}
}
I'm currently trying to build an AR Chess app and I'm having trouble getting the movement of the pieces working.
I would like to be able to tap on a chess piece, then the legal moves it can make on the chess board will be highlighted and it will move to whichever square the user tapped on.
Pic of the chess board design and nodes:
https://gyazo.com/2a88f9cda3f127301ed9b4a44f8be047
What I would like to implement:
https://imgur.com/a/IGhUDBW
Would greatly appreciate any suggestions on how to get this working.
Thanks!
ViewController Code:
import UIKit
import SceneKit
import ARKit
class ViewController: UIViewController, ARSCNViewDelegate {
#IBOutlet var sceneView: ARSCNView!
override func viewDidLoad() {
super.viewDidLoad()
// Set the view's delegate
sceneView.delegate = self
// Show statistics such as fps and timing information
sceneView.showsStatistics = true
// Add lighting to the scene
sceneView.autoenablesDefaultLighting = true
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
// Create a session configuration to track an external image
let configuration = ARImageTrackingConfiguration()
// Image detection
// Reference which group to find the image to detect in the Assets folder e.g. "Detection Card"
if let imageDetect = ARReferenceImage.referenceImages(inGroupNamed: "Detection Card", bundle: Bundle.main) {
// Sets image tracking properties to the image in the referenced group
configuration.trackingImages = imageDetect
// Amount of images to be tracked
configuration.maximumNumberOfTrackedImages = 1
}
// Run the view's session
sceneView.session.run(configuration)
}
// Run when horizontal surface is detected and display 3D object onto image
// ARAnchor - tells a certain point in world space is relevant to your app, makes virtual content appear "attached" to some real-world point of interest
func renderer(_ renderer: SCNSceneRenderer, nodeFor anchor: ARAnchor) -> SCNNode {
// Creates 3D object
let obj = SCNNode()
// Check if image detected through camera is an ARImageAnchor - which contains position and orientation data about the image detected in the session
if let imageAnchor = anchor as? ARImageAnchor {
// Set dimensions of the horizontal plane to be displayed onto the image to be the same as the image uploaded
let plane = SCNPlane(width: imageAnchor.referenceImage.physicalSize.width, height: imageAnchor.referenceImage.physicalSize.height)
// Display mild transparent layer onto detected image
// This is to ensure image detection works by display a faint layer on the image
plane.firstMaterial?.diffuse.contents = UIColor(white: 1.0, alpha: 0.2)
// Set geometry shape of the plane
let planeNode = SCNNode(geometry: plane)
// Flip vertical plane to horizontal plane
planeNode.eulerAngles.x = -Float.pi / 2
obj.addChildNode(planeNode)
// Initialise chess scene
if let chessBoardSCN = SCNScene(named: "art.scnassets/chess.scn") {
// If there is a first in the scene file
if let chessNodes = chessBoardSCN.rootNode.childNodes.first {
// Displays chessboard upright
chessNodes.eulerAngles.x = Float.pi / 2
// Adds chessboard to the overall 3D scene
obj.addChildNode(chessNodes)
}
}
}
return obj
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
// Pause the view's session
sceneView.session.pause()
}
}
You will need to add gestures on to your view and use the ARSceneViews hitTest method to detect what the gesture is touching in your scene. You can then update the positions based on the movement from the gestures.
Here is a question that deals with roughly the same requirement of dragging nodes around.
Placing, Dragging and Removing SCNNodes in ARKit
First, you need to add a gesture recognizer for tap into your viewDidLoad, like this:
let tapGesture = UITapGestureRecognizer(target: self, action: #selector(handleTap(_:)))
myScnView.addGestureRecognizer(tapGesture)
Then realize the handler function:
#objc
func handleTap(_ gestureRecognize: UIGestureRecognizer) {
// HERE YOU NEED TO DETECT THE TAP
// check what nodes are tapped
let location = gestureRecognize.location(in: myScnView)
let hitResults = myScnView.hitTest(location, options: [:])
// check that we clicked on at least one object
if hitResults.count > 0 {
// retrieved the first clicked object
let tappedPiece = hitResults[0].node
// HERE YOU CAN SHOW POSSIBLE MOVES
//Ex. showPossibleMoves(for: tappedPiece)
}
}
Now, to show the possible moves, you need to identify all quadrants and your node position on the chessboard.
To do this, you can assign a name or a number, or a combination of letter and number, or moreover a combination of numbers. (I suggest combination of number, like row 1 column 1, like a matrix).
let's take my suggestion, so you can name each quadrant 1.1 1.2 ... 2.1 2.2 and so on.
Now, to detect where your piece is, you can check contact with the PhysicsContactDelegate.
Now you have the tappedPiece and the place where it is, so you have to define the rule for the pieces, for example:
let rules = ["tower":"cross"] //add the others
N.B You can choose what you want to define the rules.
Let's take my suggestion for good, now you should create the function to highlight:
func highlight(quadrant: SCNNode){
quadrant.geometry?.firstMaterial?.emission.contents = UIColor.yellow
}
Finally the showPossibleMoves(for: tappedPiece) could be something this:
func showPossibleMoves(for piece: SCNNode){
let pieceType = piece.name //You have to give the name as you did into your rules variable
//ex. if you have rules like ["tower":"cross"] you have to set all towers name to "tower"
let rule = rules[pieceType]
switch rule{
case "cross":
//you have to highlight all nodes on the right, left, above and bottom
// you can achieve this by selecting the start point and increase it
//assuming you named your quadrants like 1.1 1.2 or 11 12 13 ecc...
let startRow = Int(startQuadrant.name.first)
let startColumn = Int(startQuadrant.name.last)
//Now loop the highlight on right
for column in startColumn+1...MAX_COLUMN-1{
let quadrant = myScnView.scene.rootNode.childNode(withName:"\(startRow).\(column)" , recursively: true)
// call highlight function
highlight(quadrant: quadrant)
}
//Now loop for above quadrants
for row in startRow+1...MAX_ROW-1{
let quadrant = myScnView.scene.rootNode.childNode(withName:"\(row).\(startColumn)" , recursively: true)
// call highlight function
highlight(quadrant: quadrant)
}
//DO THE SAME FOR ALL DIRECTIONS
}
// ADD ALL CASES, like bishop movements "diagonals" and so on
}
NOTE: In the handlerTap function you have to check what you're tapping, for example, to check if you're tapping on a quadrant after selecting a piece (you want to move you're piece) you can check a boolean value and the name of the selected node
//assuming you have set the boolean value after selecting a piece
if pieceSelected && node.name != "tower"{
//HERE YOU CAN MOVE YOUR PIECE
}
In the AR example project of apple there is an option for placing a chair in the room. What do I need to do to place multiple chairs in the code?
Would a simple append function do the trick?
When I tap on the chair option I need the first chair to be placed in the plane. If I tap again the option the chair should be placed once again. And I know I will need a delete function for this too. So how can I detect a long tap by the user?
A basic tap function to add a ball each time you tap the display.
#objc func handleTap(_ gesture: UITapGestureRecognizer) {
let results = self.sceneView.hitTest(gesture.location(in: gesture.view), types: ARHitTestResult.ResultType.featurePoint)
guard let result: ARHitTestResult = results.first else {
return
}
// create a simple ball
let sphereNode = SCNNode(geometry: SCNSphere(radius: 0.2)
// create position of ball based on tap result
let position = SCNVector3Make(result.worldTransform.columns.3.x, result.worldTransform.columns.3.y, result.worldTransform.columns.3.z)
// set position of ball before adding to scene
sphereNode?.position = position
// each tap adds a new instance of the ball.
self.sceneView.scene.rootNode.addChildNode(sphereNode!)
}
If you need the full swift code to get started...take a look at this earlier post adds a cube.scn from a remote url
You can do long press with
#objc func longPress(_ gesture: UILongPressGestureRecognizer) {
}
But its better to just detect you've tapped on an existing sphereNode you want to remove. You could add something like this to the above function.
let tappedNode = self.sceneView.hitTest(gesture.location(in: gesture.view), options: [:])
if !tappedNode.isEmpty {
let node = tappedNode[0].node
node.removeFromParent()
} else {
// add my new node
}