Capture output of Qt3D Rendering

I am sorry if I am Posting this on wrong place or type.

Req: Print out of 3D structure through QPainter with in QRect.

How cam I use normal QPainter for Qt3D rendering because I want to take print (or render somewhere else like on any widget, window,etc) of current static 3d Structure on root entity. Or is there any other better way to achieve this.

Because I already have my reporter class which gives QPainter and QRect So that next user use this QPianter to render any thing within this QRect. And the rest of the thins like printing, saving rendered object on pdf, etc is already handled by this reporter class.

Please find the attachment of my 3D structure which I created through Qt3D .
Please let me know if you want any other info .
Thank you