Rendering something at the location of the hitResult
To render a node in the 3D scene based on the found hit location, it is necessary
to retrieve the position and orientation of the hit test result relative to the world coordinate system.
This is done by using the property worldTransform.
This is a transform matrix that indicates the intersection point between the detected surface and the ray that created the hit test result.
A hit test projects a 2D point in the image or view coordinate system along a ray into the 3D world space and reports results where that line intersects detected surfaces.
In order to translate this into a location within 3D space, x,y,z coordinates are needed.
This can be done by using SCNVector3Make as follows:
func renderSomethingHere(hitFeature: ARHitTestResult){
let hitTransform = SCNMatrix4(hitFeature.worldTransform)
// get coordinate for node
let hitPosition = SCNVector3Make(hitTransform.m41,
hitTransform.m42,
hitTransform.m43)
//create a clone of an existing node
let node = self.someSCNNode!.clone()
// set the position within 3D space
node.position = hitPosition
// add the node to the ARSCNScene
self.sceneView.scene.rootNode.addChildNode(node)
}
In the above example a SCNnode is cloned, positioned and then added to the scene as child node.
Let’s see how the node is created:
AR in Entertainment - Stuttgart Media University, Semesterproject Winterterm 2017-18
