Draw SceneKit object between two points

Question

Having made some progress in the geometry side of things I\'m moving on to putting together an entire scene. That scene has a couple dozen objects, each defined by a boundin

Answer 1

Here's a solution using simd and quaternions for the rotation. I based the extension off of the answer by @Bersaelor.

I used this derivation (https://stackoverflow.com/a/1171995/6693924) to create the quaternion from two vectors. Hope this helps.

extension SCNNode {
    static func lineNode(from: simd_float3, to: simd_float3, radius : CGFloat = 0.25) -> SCNNode
    {
        let vector = to - from
        let height = simd_length(vector)

        //cylinder
        let cylinder = SCNCylinder(radius: radius, height: CGFloat(height))
        cylinder.firstMaterial?.diffuse.contents = UIColor.white

        //line node
        let lineNode = SCNNode(geometry: cylinder)

        //adjust line position
        let line_axis = simd_float3(0, height/2, 0)
        lineNode.simdPosition = from + line_axis

        let vector_cross = simd_cross(line_axis, vector)
        let qw = simd_length(line_axis) * simd_length(vector) + simd_dot(line_axis, vector)
        let q = simd_quatf(ix: vector_cross.x, iy: vector_cross.y, iz: vector_cross.z, r: qw).normalized

        lineNode.simdRotate(by: q, aroundTarget: from)
        return lineNode
    }
}