Drawing a line between two points in SceneKit / iOS / Swift

line.swift

  
    func line(from p1: SCNVector3, to p2: SCNVector3) -> SCNNode? {
        // Draw a line between two points and return it as a node
        var indices = [Int32(0), Int32(1)]
        let positions = [p1, p2]
        let vertexSource = SCNGeometrySource(vertices: positions)
        let indexData = Data(bytes: &indices, count:MemoryLayout<Int32>.size * indices.count)
         let element = SCNGeometryElement(data: indexData, primitiveType: .line, primitiveCount: 1, bytesPerIndex: MemoryLayout<Int32>.size)
        let line = SCNGeometry(sources: [vertexSource], elements: [element])
        let lineNode = SCNNode(geometry: line)
        return lineNode
    }

// Draws a (very thin) line between two points.
// Not sure how to set the color though - materials didn't seem to do much

I have developed a simple project that allows drawing any width and color line through multiple points. It also supports loops and mittered (sharp) joins. https://github.com/bialylis/ThickRedLine