private void UpdateChildrenMatrices()
{
var mat = Matrix4x4.Identity;
mat.M14 = FloatHelpers.SignalingNaN;
mat.M24 = FloatHelpers.SignalingNaN;
mat.M34 = FloatHelpers.SignalingNaN;
mat.M44 = FloatHelpers.SignalingNaN;
Matrix4x4[] matrices = new Matrix4x4[NumBounds];
matrices.AsSpan().Fill(mat);
CurrentMatrices = new SimpleArray <Matrix4x4>(matrices);
LastMatrices = new SimpleArray <Matrix4x4>((Matrix4x4[])matrices.Clone());
}