how do you get the vertex data from an an abject from the houdini viewport. I want to render an object and then display it in a vr headset

Not sure what you mean with the vertex data?
But yes, it would be incredibly usefull to have the Houdini Viewport connected to a VR HMD.
Already opened a thread about it years ago.
No progress so far unfortunately however.

https://www.sidefx.com/forum/topic/55616/ [www.sidefx.com]