how to add MeshGeometry3D dynamically to Helixviewport

Question

I want add MeshGeometry3D dynamically to Helixviewport.

I am having multiple MeshGeometry3D . Now I want to append multiple MeshGeometry3D dynamically to Helixviewport (HelixToolkit.Wpf.SharpDX). I tried many methods , but I cant achieve it!!!!!!!

I have tried with Modelvisual3d.children.append(),helixviewport.children.append() but I cant achieve it

USING LIBRARIES(HelixToolkit.Wpf.SharpDX)