Symmetry list

[yfji]

Hi! Thanks for your work! I want to known if the BFM2017 and BFM2019 provide the symmetry list of vertices like BFM2009?

[Andreas-Forster]

Hi there,

I think the symmetry for the BFM2017 should be the same as for the BFM2009.

For the BFM2019 you can build it yourself, the reference should be mirrored at the z-y plane up to numerical inaccuracies. In scala you can use something similar to the following code to find a list of the point index pairs:

import java.io.File

import scalismo.utils.Random
import scalismo.faces.io.MoMoIO

object Symmetry extends App {
  scalismo.initialize()
  implicit val rng = Random(1024l)

  val momo = MoMoIO.read(new File("model2019.h5")).get

  val points = momo.referenceMesh.pointSet.points.toIndexedSeq
  val mirroredPoints = points.map(pt => pt.copy(x = -pt.x))
  val symmetryList = for ((pt, idx) <- points.zipWithIndex) yield {
    (idx, mirroredPoints.indexWhere(p => (p - pt).norm < 1.0e-4))
  }

  // check it for the first few points
  symmetryList.take(10).foreach(p => println(s" ${p._1}:${points(p._1)} ${p._2}:${points(p._2)}"))
}

Best, Andreas