Nose and foot coordinates using key-point R-CNN and DensePose.

Hello everyone!
Given an image, say, [this](https://bandat-nhontrach.com/images/person-standing-png-3.jpg), I am using the Key-Point R-CNN (from detectron2) to get the coordinates of the nose and either foot. Using [this code](https://github.com/linjunyu/Detectron2-Densepose-IUV2XYZ/blob/master/Detectron2-densepose-IUV2XYZ.ipynb), I get a [3D-reconstruction](https://imgur.com/2Rug5qh). DensePose changes the person's pose (as shown in the previous link). **Using the 3D model and the key-points, how can I get the 3D coordinates of the nose and feet?** (As of right now, they do not match).
I used the projection of the model to the [Y-Z plane ](https://i.imgur.com/UvZNl8W.jpg) then tried looking for the right and left most maxima but couldn't find a good enough algorithm.

I hope this is the correct place to post this, if not, please close this issue and if possible refer me to to correct place.

Thanks!