Rendering a motion capture model to be able to then use in Nuke

[saundersj7PB45]

I'm rendering a model connected to a motion capture.  The first render, the model would leave the screen periodically when composited over a video file in Nuke.  I found tutorials on adding the model as a parent to the camera so it would follow the model.  I'm not sure if I did it right. 

The first render I did a few weeks ago was dark.  I figured out the dark screen (with forum help) on the render by adding a skydome light and changing the camera visibility of the skydome light to 0.  That allows the model to be seen on the render.

I've been jumping back and forth between Motive (Optitrack motion capture software), Maya, and Nuke and am trying to nail down the full workflow to teach my class.  When rendering again in the Arnold renderer in Maya (after attempting to connect the model to the camera as a parent), the output is again dark.  The settings are all the same as the first render before I tried setting the model as a parent to the camera.  

Since I'm not sure if I did the process of attaching the camera to the model correctly (so it will stay on screen the whole time when compositing over another video in Nuke) and the render is again dark, would it be possible to pay for support so that I can do a screen share with a tech person at Autodesk? 

I'm spending a huge amount of time in Maya and just want to be able to attach the motion capture's movements to a model (which I've figured out) and then render it as an image sequence or exr file so that I can composite it in Nuke and have it stay on the screen the whole time over the other video.  I think a screen share would be more efficient than trying to find specific tutorials.  Thank you.