Rounding positional data from ARKit

Question

I have this code that gets X, Y, Z positions from each frame in ARKit.

let CamPosition = SCNVector3(transform.m41, transform.m42, transform.m43)

How would I round the numbers down because they output occasionally in scientific notation like this?

SCNVector3(x: 7.276927e-09, y: 2.4679738e-09, z: 3.395949e-10)

Instead of the desired output like this:

SCNVector3(x: 0.026048008, y: 0.0069037788, z: 0.010655182)

Any help is greatly appreciated!

Answer 1

Rounding to Meters

For that you can use three holy methods: round(_:), and ceil(_:), and floor(_:).

import SceneKit
import Foundation

let node = SCNNode()

node.position = SCNVector3(x: floor(12.856288),
                           y:  ceil(67.235459),
                           z: round(34.524305))


node.position.x    //  12
node.position.y    //  68   
node.position.z    //  35

Rounding XYZ values to integer, you make them to translate intermittently (discretely) in meters.

Rounding to Centimeters

Rounding XYZ values to 2 decimal places:

node.position = SCNVector3(x: round(12.856288 * 100) / 100.0,
                           y: round(67.235459 * 100) / 100.0,
                           z: round(34.524305 * 100) / 100.0)

node.position.x    //  12.86   (hundredths)
node.position.y    //  67.24
node.position.z    //  34.52