I'm trying to scale down a SCNNode that contains other nodes, but itself has no geometries. I read the documentation on scale, but I'm a little skeptical that they would make positioning relative to the parent, but not scale.
The problem:
scale does not seem to do anything.
Here's a snippet of my SCNNode sub-class
addChildNode(Node1)
addChildNode(Node2)
Node2.addChildNode(Node21)
addChildNode(Node3)
print("pre-scale", self.scale)
// prints SCNVector3(x: 1.0, y: 1.0, z: 1.0)
self.scale = SCNVector3(x:0.05, y:0.05, z:0.05)
print("post-scale", self.scale)
// prints SCNVector3(x: 0.05, y: 0.05, z: 0.05)
Visibly, nothing changes.
I've considered doing a loop and applying the scaling factor to every child node, but I think the relative positions will get all messed up.
I'd like everything to scale as one and retain its integrity. Is there something I'm missing?
Try to scale all child nodes one by one:
let newScale = Float(0.05)
for c in self.childNodes
{
c.scale = SCNVector3Make(newScale, newScale, newScale)
}
The parent node may not assign to any camera. try adding the camera to the node and try the scaling.
let cameraNode = SCNNode()
cameraNode.camera = SCNCamera()
cameraNode.position = SCNVector3(x: 0, y: 0, z: 5)
scene.rootNode.addChildNode(cameraNode)
parentNode.scale = SCNVector3(0.5, 0.5, 0.5)
Related
I am learning SceneKit. And I have a simple scene with a single shape and a light.
Here is the light code:
let lightNode = SCNNode()
lightNode.light = SCNLight()
lightNode.light?.castsShadow = true
lightNode.light?.type = .directional
lightNode.light?.intensity = 1000
lightNode.position = SCNVector3(x: -6, y: 0, z: 30)
lightNode.rotation = SCNVector4(x: 0, y: 0, z: 1.0, w: 3.14 / 2)
scene.rootNode.addChildNode(lightNode)
It produces the following result:
When I comment/uncomment lightNode.rotation the result remains the same. However I expect, that this circle highlight at the center of the shape changes or disappears.
You are rotating the directional light around the z-axis and it will have no effect, because your light source is directed along the -Z axis by default. Try rotating your Sun light source around the x-axis or y-axis.
lightNode.rotation = SCNVector4(x: 1, y: 0, z: 0, w: -.pi / 15)
P. S.
There is no sense in using .position for Sun light. For this type of light, only orientation matters.
How can I enable the user to move the object using the right and left arrows I put below, instead of manually moving it?
"allowscameracontrol" allows the user to rotate the object with their hand. But I just want it to be rotated using arrows.
** -> sceneView.allowsCameraControl = true**
import UIKit
import SceneKit
class ViewController: UIViewController {
#IBOutlet weak var sceneView: SCNView!
override func viewDidLoad() {
super.viewDidLoad()
// 1: Load .obj file
let scene = SCNScene(named: "converse_obj.obj")
//Add camera node
let cameraNode = SCNNode()
cameraNode.camera = SCNCamera()
//Place camera
cameraNode.position = SCNVector3(x: 0, y: 10, z: 35)
//*Set camera on scene
scene?.rootNode.addChildNode(cameraNode)
//Adding light to scene
let lightNode = SCNNode()
lightNode.light = SCNLight()
lightNode.light?.type = .omni
lightNode.position = SCNVector3(x: 0, y: 10, z: 35)
scene?.rootNode.addChildNode(lightNode)
// 6: Creating and adding ambien light to scen
let ambientLightNode = SCNNode()
ambientLightNode.light = SCNLight()
ambientLightNode.light?.type = .ambient
ambientLightNode.light?.color = UIColor.darkGray
scene?.rootNode.addChildNode(ambientLightNode)
// Allow user to manipulate camera
sceneView.allowsCameraControl = true
// Set background color
sceneView.backgroundColor = UIColor.white
// Allow user translate image
sceneView.cameraControlConfiguration.allowsTranslation = false
// Set scene settings
sceneView.scene = scene
}
}
I haven't used SceneKit before.
I'm not sure if you would want to rotate your camera or rotate the node that contains the object. From the way it's named, it makes it sound like allowsCameraControl rotates the camera. In any case you would use rotationMatrixAroundZ to create a rotation matrix, and then multiply that by the matrix for whichever thing you want to rotate.
If rotating the camera is what you want to do, your code might look like this:
func rotateCameraZByDegrees(_ zRotation: Double) {
let radians = zRotation / 180.0 * Double.pi
let rotationZ = rotationMatrixAroundZ(radians: radians)
cameraNode.transform = SCNMatrix4(simd_mul(simd_float4x4(cameraNode.transform), rotationZ))
}
If you instead want to rotate your object's node, and your object's node is named sneakersNode, change the last line to:
sneakersNode.transform = SCNMatrix4(simd_mul(simd_float4x4(sneakersNode.transform), rotationZ))
This post [31881911] in stackO shows you some examples for arrow keys.
Turn allowsCameraControl = false
This post [68506605] see my answer - creating a camera control class makes things a lot easier.
For your rotation, just rotate the object directly - several ways to do this.
func resetRotation()
{
for (_, vNode) in displayNodes
{
vNode.node.removeAllActions()
}
vRotate0 = SCNAction.rotateTo(x: 0, y: 0, z: 0, duration: 2)
vRotate1 = SCNAction.rotateBy(x: 0, y: CGFloat(GLKMathDegreesToRadians(450)), z: 0, duration: 3)
vRotate2 = SCNAction.rotateBy(x: 0, y: CGFloat(GLKMathDegreesToRadians(-90)), z: 0, duration: 1)
vRotate3 = SCNAction.rotateBy(x: CGFloat(GLKMathDegreesToRadians(-45)), y: 0, z: 0, duration: 1)
vRotate4 = SCNAction.rotateBy(x: CGFloat(GLKMathDegreesToRadians(45)), y: 0, z: 0, duration: 1)
seq = SCNAction.sequence([vRotate0, vRotate1, vRotate2, vRotate3, vRotate4, vRotate3, vRotate4])
allSeq = SCNAction.repeatForever(seq)
for (_, vNode) in displayNodes
{
vNode.node.runAction(allSeq)
}
}
You could use some sequences - so your object could do a 360 and stop, come back 90 at a slower pace, whatever you want. The above repeats forever, but you can take that out.
Or just on Left key press, rotate Y += n degrees.
I have ARKit artwork app. And I want my artworks to have a shadow just behind it. The shadow mustn't be dynamic. Just static shadow.
I've tried to add a plane behind the artwork. And set a shadow to it. But I discovered that it is not easy.
Can you help me?
let shadow = SCNPlane(width: artwork.size.width * 0.0254 + 0.03, height: artwork.size.height * 0.0254 + 0.015)
let layer = CALayer()
layer.frame = CGRect(origin: .zero, size: CGSize(width: shadow.width, height: shadow.height))
layer.shadowColor = UIColor.black.cgColor
layer.shadowOpacity = 1
layer.shadowOffset = .zero
layer.shadowRadius = 10
shadow.firstMaterial?.diffuse.contents = layer
The shadow should be like in UIKit's UIView. But this code just doesn't work.
I need something like
UPDATED.
In order to cast and receive a shadows from 3D lights, you have to use a 3D primitives (like cube, sphere, cylinder, etc), or 3D models in such formats as .usdz, .dae or .obj.
Shadow on a visible plane.
Use the following code to test how light generates shadows for 3D geometry:
let scene = SCNScene()
let lightNode = SCNNode()
lightNode.light = SCNLight()
lightNode.light!.type = .spot
lightNode.light!.castsShadow = true
lightNode.light!.shadowMode = .deferred
lightNode.rotation = SCNVector4(x: -1, y: 0, z: 0, w: CGFloat.pi/2)
lightNode.position = SCNVector3(x: 0, y: 20, z: 0)
scene.rootNode.addChildNode(lightNode)
let sphereNode = SCNNode()
sphereNode.geometry = SCNSphere(radius: 2)
sphereNode.position = SCNVector3(x: 0, y: -2, z: 0)
scene.rootNode.addChildNode(sphereNode)
let planeNode = SCNNode()
planeNode.geometry = SCNPlane(width: 15, height: 15)
planeNode.position = SCNVector3(x: 0, y: -5, z: 0)
planeNode.rotation = SCNVector4(x: -1, y: 0, z: 0, w: CGFloat.pi/2)
planeNode.geometry?.materials.first?.diffuse.contents = UIColor.red
scene.rootNode.addChildNode(planeNode)
Shadow on invisible plane.
In case you need an invisible plane that receives a shadow, use the following code:
planeNode.geometry?.materials.first?.colorBufferWriteMask = []
planeNode.geometry?.materials.first?.writesToDepthBuffer = true
planeNode.geometry?.materials.first?.lightingModel = .constant
Fake shadow.
And if you want to use a fake shadow written as a .png (png file format can hold 4 channels) texture on geometry (with a premultiplied alpha channel – RGB x A), use the following approach:
planeNode.geometry?.materials.first?.diffuse.contents = UIImage(named: "shadow.png")
lightNode.light!.castsShadow = false
Here's my answer on fake shadows.
And here's your premultiplied shadow in .png format (just drag-and-drop it on your desktop):
You can change its size and transparency and, of course, you can blur it.
My node setup:
let node = SCNNode()
node.position = SCNVector3(0.0, 0.0, 0.0)
I then wish to rotate the node by 90 degrees to the left which can be achieved with:
node.transform = SCNMatrix4Rotate(node.transform, .pi/2, 0.0, 1.0, 0.0)
Next, I want to translate the node forward one unit along the negative z axis relative to current rotation and end up with:
node.position = SCNVector3(-1.0, 0.0, 0.0)
I have no idea how to get from the rotation of the node to the position of the node programmatically.
Basically node begins at (0, 0, 0), its forward vector is the -z axis, node turns left and moves one unit forward to end up at (-1, 0, 0).
This isn't working:
func move(_ direction: moveDirection) {
switch direction {
case .forward: characterNode.position = SCNVector3(characterNode.position.x, characterNode.position.y, characterNode.position.z - 1.0)
case .left: characterNode.pivot = SCNMatrix4Rotate(characterNode.pivot, -.pi/32, 0.0, 1.0, 0.0)
case .backward: characterNode.position = SCNVector3(characterNode.position.x, characterNode.position.y, characterNode.position.z + 1.0)
case .right: characterNode.pivot = SCNMatrix4Rotate(characterNode.pivot, .pi/32, 0.0, 1.0, 0.0)
}
}
Assuming I have understood you correctly, once you have rotated your SCNNode, you want to move it forward it in that direction.
This can be done by using the worldFront value which is simply:
The local unit -Z axis (0,0,-1) in world space.
As such this may be the answer you are looking for:
//1. Create A Node Holder
let nodeToAdd = SCNNode()
//2. Create An SCNBox Geometry
let nodeGeometry = SCNBox(width: 0.2, height: 0.2, length: 0.2, chamferRadius: 0)
nodeGeometry.firstMaterial?.diffuse.contents = UIColor.cyan
nodeGeometry.firstMaterial?.lightingModel = .constant
nodeToAdd.geometry = nodeGeometry
//3. Position It 1.5m Away From The Camera
nodeToAdd.position = SCNVector3(0, 0, -1.5)
//4. Rotate The Node By 90 Degrees On It's Y Axis
nodeToAdd.rotation = SCNVector4Make(0, 1, 0, .pi / 2)
//5. Add The Node To The ARSCNView
augmentedRealityView.scene.rootNode.addChildNode(nodeToAdd)
//6. Use The World Front To Move The Node Forward e.g
/*
nodeToAdd.simdPosition += nodeToAdd.simdWorldFront * 1.2
*/
nodeToAdd.simdPosition += nodeToAdd.simdWorldFront
//7. Print The Position
print(nodeToAdd.position)
/*
SCNVector3(x: -0.999999881, y: 0.0, z: -1.50000024)
*/
How can I draw a 3D object (preferably a rectangle) with core graphics in Swift?
Is it possible or do I have to use a different library?
Is it possible with UIKit?
Borrowing from this answer: https://stackoverflow.com/a/24127282/887210
The key part for your question is:
SCNBox(width: 1, height: 4, length: 9, chamferRadius: 0)
This draws a rectangular box with SceneKit and UIKit. It's set up to be used in a custom UIViewController in your project but it can easily be adapted to other uses.
The example code:
override func loadView() {
// create a scene view with an empty scene
let sceneView = SCNView(frame: CGRect(x: 0, y: 0, width: 300, height: 300))
let scene = SCNScene()
sceneView.scene = scene
// default lighting
sceneView.autoenablesDefaultLighting = true
// a camera
let cameraNode = SCNNode()
cameraNode.camera = SCNCamera()
cameraNode.position = SCNVector3(x: 0, y: 0, z: 15)
scene.rootNode.addChildNode(cameraNode)
// a geometry object
let box = SCNBox(width: 1, height: 4, length: 9, chamferRadius: 0)
let boxNode = SCNNode(geometry: box)
scene.rootNode.addChildNode(boxNode)
// configure the geometry object
box.firstMaterial?.diffuse.contents = UIColor.red
box.firstMaterial?.specular.contents = UIColor.white
// set a rotation axis (no angle) to be able to
// use a nicer keypath below and avoid needing
// to wrap it in an NSValue
boxNode.rotation = SCNVector4(x: 1, y: 1, z: 0.0, w: 0.0)
// animate the rotation of the torus
let spin = CABasicAnimation(keyPath: "rotation.w") // only animate the angle
spin.toValue = 2.0*Double.pi
spin.duration = 10
spin.repeatCount = HUGE // for infinity
boxNode.addAnimation(spin, forKey: "spin around")
view = sceneView // Set the view property to the sceneView created here.
}
This question is similar to the question whether it is possible to draw a 3D object on a sheet of paper which is, between, 2D. The third dimension effect is achieved drawing additional lines as the projections. The third dimension could also be perceived through the motion, so, Core Animation is a possible companion to Core Graphics but it requires a lot of calculation, as result, it is quite complicated (using Core Animation).
Actually, SceneKit or Metal are the options to draw 3D models using Swift.