Once the user has scanned the environment and that I detected a plane, I would like the world origin anchor, which is the device position when the app opens (which is the origin of the 3D world), to be reset to where my device is right now so that the user can see my AR objects in front of him.
(my objects are floating and not related to the floor but detecting a plane makes the objects more stable)
I didn't find a way to do that. It's linked to ARConfiguration but it doesn't seem like we can update the coordinate system without resetting all the tracking. Do you have any idea?
According to this post link, the documentation of the rootNode says:
You should not modify the transform property of the root node.
I still tried affecting the camera position to the position of the rootNode but it didn't change anything.
So it seems like the only way is to create a new node and use it as a rootNode from where we are.
Related
I built a complete structure as a node (with its child nodes) and the user will walk through it using ARKit.
At some point, if the user cannot continue because of some real obstacle in the real world, I added a "pause" button which should freeze whatever the user currently sees in front of the camera, the user could then move freely to some other open space and when the user will release the pause button he/she will be able to resume where they left off (only someplace else in the real world).
A while ago I asked about it in the Apple Developer forum and an Apple Frameworks Engineer gave the following reply:
For "freezing" the scene, you could transform the anchor's position (in world coordinates) to camera coordinates, and then anchor your content to the camera. This will give you the effect that the scene is "frozen", i.e., does not move relative to the camera.
I'm currently not using an anchor because I don't necessarily need to find a flat surface. Rather, my node is placed at a certain position relative to where we start at (0,0,0).
My question is how do I exactly do what the Apple engineer told me to do?
I have the following code which I'm still stuck with. When I add the node to the camera (pointOfView, last line of the code below), it does freeze in place, but I can't get it to freeze in the same position and orientation as it was before it was frozen.
#IBAction func pauseButtonClicked(_ sender: UIButton) {
let currentPosition = sceneView.pointOfView?.position
let currentEulerAngles = sceneView.pointOfView?.eulerAngles
var internalNodeTraversal = lastNodeRootPosition - currentPosition! // for now, lastNodeRootPosition is (0,0,0)
internalNodeTraversal.y = lastNodeRootPosition.y + 20 // just so it’s positioned a little higher in front of the camera
myNode?.removeFromParentNode() // remove the node from the Real World view. Looks like this line has no effect and just adding the node as a child to the camera (pointOfView) is enough, but it feels more right to do this anyway.
myNode?.position = internalNodeTraversal // the whole node is moved respectively in the opposite direction from the root to where I’m standing to reposition the camera in my current position inside the node
// myNode?.eulerAngles = (currentEulerAngles! * -1) — this code put the whole node in weird positions so I removed it
myNode?.eulerAngles.y = currentEulerAngles!.y * -1 // opposite orientation of the node so the camera will be oriented in the same direction
myNode?.eulerAngles.x = 0.3 // just tilting it up a little bit to have a better view, more similar to the view as before it was locked to the camera
// I don’t think I need to change the eulerAngles.z
myNode!.convertPosition(internalNodeTraversal, to: sceneView.pointOfView) // I’m not sure I wrote this correctly. Also, this line doesn’t seem tp change anything
sceneView.pointOfView?.addChildNode(myNode!) // attaching the node to the camera so it will remain stuck while the user moves around until the button is released
}
So I first calculate where in the node I'm currently standing and then I change the position of the node in the opposite direction so that the camera will now be in that position. That seems to be correct.
Now I need to change the orientation of the node so that it will point in the right direction and here things get funky. I've been trying so many things for days now.
I use the eulerAngles for the orientation. If I set the whole vector multiplied by -1, it would show weird orientations. I ended up only using the eulerAngles.y which is the left/right orientation and I hardcoded the x orientation (up/down).
Ultimately what I have in the code above is the closest that I was able to get. If I'm pointing straight, the freeze will be correct. If I turn just a little bit, the freeze will be pretty close as well. Almost the same as what the user saw before the freeze. But the more I turn, the more the frozen image is off and more slanted. At some point (say I turn 50 or 60 degrees to the side) the whole node is off the camera and cannot be seen.
Somehow I have a feeling that there must be an easier and more correct way to achieve the above.
The Apple engineer wrote to "transform the anchor's position (in world coordinates) to camera coordinates". For that reason I added the "convertPosition" function in my code, but a) I'm not sure I used it correctly and b) it doesn't seem to change anything in my code if I have that line or not.
What am I doing wrong?
Any help would be very much appreciated.
Thanks!
I found the solution!
Actually, the problem I had was not even described as I didn't think it was relevant. I built the AR nodes 2 meters in front of the origin (-2 for the z-coordinate) while the center of my node was still at the origin. So when I changed the rotation or eulerAngles, it rotated around the origin so my nodes moved in a large curve and in fact also changed their position as a result.
The solution was to use a simdPivot. Instead of changing the position and rotation of the node itself, I created a translation matrix and a rotation matrix which was at the point of the camera (where the user is standing) and I then multiplied both matrices. Now when I added the node as a child of the camera (pointOfView) this would freeze the image and in effect show exactly what the user was seeing before it was frozen as the position is the same and the rotation is exactly around the user's standing position.
I'm working on developing iOS AR application using ARKit + Core location. And the points which are displayed on the map using coordinates move from place to place when I go. But I need they are displayed on the same place.
Here you can see the example of what I mean:
https://drive.google.com/file/d/1DQkTJFc9aChtGrgPJSziZVMgJYXyH9Da/view?usp=sharing
Could you help to handle with this issue? How can I have fixed places for points using coordinates? Any ideas?
Thanks.
Looks like you attach objects to planes. However, when you move the ARKit extends the existing planes. As a result if you put points, for example, at the center of the plane, then the center is always updated. You need to recalculate the coordinates of the point and place objects correctly.
The alternative is not to add objects to planes (or in relation to them). If you need to "put" object on a plane, then the best way is to wait, until the plane will be directed enough (it will not change his direction significantly if you will move), then select a point on the plane where you want to put your object, then convert this point coordinate to global coordinates (as a result if plane will change his size the coordinate you have will not be changed at all), and finally put object in root (or another object that it's not related to the plane).
I'm working on an app with AR feature. I want to be able to place a 3D model that I have on a horizontal plane that has been detected. So inside the renderer(didAdd) delegate function, I added a node for my 3D model, and set its position to the center of the plane anchor. However, when I run the app to test it, my model is floating on top of the plane instead of standing directly on top of it. My guess is that there is some translation that needs to be done with the coordinates, but don't know about the details. Can somebody give me some pointers?
I am developing an iOS in-store navigation app for a retail store using AR Scene Kit which should resembles as Lowe's Vision Navigation. Hence, At first I want to programatically plot the position of any xyz product which is available in the store in an AR Scene Kit irrespective of the camera's initial position, but the position of the Product will remain same in the Store. I was totally new to AR as well as Scene Kit.
I am able to add a SCNNode in the ARSCNView but the problem will be my camera's initial position according to that only the SCNNode is plotting. Once this is done, then I need to give the in-store navigation for the selected product from my position inside the store may be using iBeacon or other equivalent.
SCNNodes operate somewhat like UIViews, in the sense that, as you said, the positions are relative to the parent node/view. For the cases where you want the position relative to the whole view or the world you can use worldTransform and -convertPosition:toNode: .
World Transform
Convert Position To Node
I have a SCNNode, and an SCNCamera. The camera is located up and in front of the node, and looks down on the node via an SCNLookAtConstraint that I have setup. However when the node moves laterally, the camera only rotates, instead of moving with the it. Is there any way to get the camera to move with the node?
You are only using SCNLookAtConstraint, which as its name says, make the camera Look At the object only. (You only need to rotate your head to look at something)
To make the Camera move with it, you will need either a SCNTransformConstraint (documentation here), or simply make the Camera Node a child of the object you want it to follow.
In case you want the Camera to smoothly follow the object, and be constrained only by a distance (as if it was dragged by a rope), the SCNTransformConstraint is the way to go.
If the transform between your node and the camera is always the same, you should consider making the camera a child node of your node. This is way more efficient and simpler than using constraints.
I made my camera node a child of the SCNNode I wanted to follow. That's another way to achieve this.