Unable to create circle using UIBezierPath and SCNShape

问题

Anyone familiar with using curved UIBezierPaths to create a SCNShape in ARKit? I'm creating a closed circle path, but I get a diamond shape in my ARKit scene.

Here is the code I use to create the bezier path and SCNShape:

let radius : CGFloat = 1.0
let outerPath = UIBezierPath(ovalIn: CGRect(x: -radius, y: -radius, width: 2* radius, height: 2* radius))

let material = SCNMaterial()
material.diffuse.contents = UIColor.blue
material.isDoubleSided = true
material.ambient.contents = UIColor.black
material.lightingModel = .constant
material.emission.contents = UIColor.blue

let shape = SCNShape(path: outerPath, extrusionDepth: 0.01)
shape.materials = [material]

let shapeNode = SCNNode(geometry: shape)
positioningNode.addChildNode(shapeNode)

I've successfully tested a rectangular bezier path, but even had issues with a rounded rect bezier path (using UIBezierPath(roundedRect:). For the rounded rect bezier path, ARKit shows the curved corners with 45 degree lines.

Thanks in advance!

UPDATE:

On the left is the initial SCNShape with UIBezierPath flatness set to 0.6. On the right is the same SCNShape with flatness set to 0.001.

回答1:

I was able to find a solution. Basically the UIBezierPath's flatness variable is used to control curvature. The default value of 0.6 was too large in my case. I ended up using a flatness of 0.001

https://developer.apple.com/documentation/scenekit/scnshape/1523432-init

来源：https://stackoverflow.com/questions/52730486/unable-to-create-circle-using-uibezierpath-and-scnshape

标签

ios

swift

scenekit

arkit

uibezierpath