Quick Tip: Be Weary of ImagePlane Gizmos.
The ImagePlane gizmo is my favourite for speedily placing an object on a card in (pseudo) 3D space. Rather than dealing with Nuke's clunky 3D system, you can easily get a handful of atmospheric smoke elements layered up and in your shot! But that convenience of fast setup time comes at a price...
If you've got 2 or 3 elements to throw into your shot, ImagePlane's are perfect! Although if you're working on a mostly-CG shot that needs polishing up with a lot of 2D elements, it's best you stick with the standard 3D Card, Camera & ScanlineRender setup. It's more annoying and time-consuming to set up for sure, but it will prevent your Nuke script from chugging along at snail's pace.
ImagePlane's in vast quantities, especially with motion blur switched on, will take a huge toll on both your GUI's interactivity & your Viewer's processing speed.
Do you have a better way? Reach out and let me know!