iOS SceneKit - Add Fresnel effect to material transparency

Question

I have a Geometry Node that pictures a human body. The material for the object is transparent

let node = newScene.rootNode.childNode(withName: "man_mesh", recursively: true)
let nodeMaterial = node?.geometry?.firstMaterial
nodeMaterial?.emission.contents = UIColor(red: 0.0, green: 0.0, blue: 1.0, alpha: 1.0)
nodeMaterial?.transparencyMode = .rgbZero
nodeMaterial?.transparent.contents = UIColor(red: 1.0, green: 1.0, blue: 1.0, alpha: 1.0)

The effect I'm trying to get is for the object to be fully transparent in areas facing the camera, but become more opaque as the polygons face sideways... this creates a sort of a shiny blue rim. something like this:

Any idea how to create this effect?

Thanks

EDIT: Another interesting point: it appears the SceneKit does support the fresnel effect. The effect affects the Reflectance map - as should be, however, once you apply transparency to your object, it also affects the reflectance (full transparency will make reflectance disappear as well)- I believe this is a conceptual mistake by Apple - a material can be transparent and still reflect light!

Answer 1

I've done some research and found an answer. To achieve this effect, you can use following code.

func ghostEffect(scene: SCNScene) {

    let sphere = SCNSphere(radius: 3)

    let material = SCNMaterial()
    material.diffuse.contents = UIColor.black
    material.reflective.contents = UIColor(red: 0, green: 0.764, blue: 1, alpha: 1)
    material.reflective.intensity = 3
    material.transparent.contents = UIColor.black.withAlphaComponent(0.3)
    material.transparencyMode = .default
    material.fresnelExponent = 4

    sphere.materials = [material]

    let node = SCNNode(geometry: sphere)

    scene.rootNode.addChildNode(node)

}

Explanation from: SCNMaterial.

transparent - An object that determines the opacity of each point in a material

reflective - An object that defines the reflected color for each point on a surface

fresnselExponent - A factor affecting the material’s reflectivity

This approach can be applied to any 3D object.

P.S. Hope it will be useful.