Revit Render Trick

Structural renders are getting used more often and the mental ray engine leaves a grey line at the horizon, here's a little trick to bypass the grey horizon line in renders, it's not great but it's quick:

1. Render an image and save to .tif or .png - This will create an alpha channel transparency with no sky, and no horizon.
2. Change the the target of the camera to be 100m or so in the air so that nothing but sky is seen, re-render and save the sky image as a .jpg - This renders really fast as there's no geometry
3. In photoshop (or image software of your choice) add the sky in behind the image.

.png image (with alpha channel)

.jpg image

composite (.jpg was rotated 180deg.)

The final image looks better once more scene assets are added and you don't need to place an expensive (in render time) tree line along the back of the image.