ViewShift from a Clean Plate

ViewShift can work from a manually‐cleaned plate as the source shot, not only from an entire shot. This tutorial shows some small scripts that accelerate setup when the clean plate is one of the frame in the main shot.

Script for Search Engines:

hi this is Russ Anderson the view shift system in SynthEyes lets you do removals and split take effects with SynthEyes relying on a 3d track and geometry you transfer pixels from one part of a shot to another either within the same shot or from a different one usually the shots are similar length so retiming doesn't give the effect away sometimes though you may want to manually clean up a single frame using a Photoshop or whatever and use that for the view shift that fits perfectly within the standard view shift approach nothing special or different is required to work from a clean plate often though the clean plate is actually one of the frames from the existing shot and in that case SynthEyes can lend a hand to make the setup easier at the end I'll talk a little about what to do at the clean plate is not from the shot being worked on for now we're going to start with a version of the car removal shot we used in the first view shift tutorial it's already soft and has the reflector mesh an animated spline it also has a light that stores the average illumination level of this tracker down here in the middle of the road you can also see the RGB curves in the graph editor this is used for illumination compensation now we could easily do a removal using this overall setup with the entire shot as the source which is what we did in the first tutorial but since this is a clean plate tutorial I've already gone and cleaned up one of the frames to use as a clean plate you could do that with Photoshop but you can probably figure out the lazy approach that I used I picked a frame near the end of the shot frame 155 more about that later we need to set up the source camera with the right location and field of view we already have that information since we solve the entire shot including for frame 155 so we're going to go to frame 155 then on the view shift menu we run the prepare for clean plate script it will do the following all of what you could do yourself it'll prompt you for the location of the clean plate it will add it to your scene as a very short single frame shot then it'll copy the camera position field of view and distortion information from the current frame to the first frame of the new shot you can see that as I scrub through the shot on the first frame its position at the camera's position on frame 155 of the overall shot the rest of the time that camera doesn't have any position at all the script will also make a copy of the illumination compensation light bringing in the illumination information from the current frame to the new shots first frame also it will adjust the view shift to set the source to the single frame camera - so our output is set up the other settings are at decent default settings so we're ready to view shift now we're done let's play the result at the end you notice that the car becomes visible that's because the clean plate doesn't contain replacement pixels for the very end of the scene basically the car drove off the end of that image so in fact there's no single frame that can be used as a clean plate for the length of this shot you know that's a limitation of the clean plate technique you need to have a clean plate that can contain all the needed pixels for the entire shot now you might sometimes decide that you want to update the main camera track if you do that you want to update the clean plates camera also so let's take a look at the track or ours and the graph editor and you can see that there's some that are fairly high so let's run cleanup trackers will turn on bad frames and select a two pixel or as the threshold now we'll refine the solve this doesn't make any dramatic changes in this particular case but we still always want the clean plate to match up exactly so we'll run the update clean plate script also it'll update the camera position field of view and distortion information it'll also update any illumination light and it'll also just as convenience it'll set the frame back to the clean plate frame just as a reminder of which one that is so at this point you could rerun the view shift now if your clean plate is not from the shot you're cleaning you should add the clean plate with ADD shot then you'll need to setup the exact camera location and field of view you might be able to get the field of view determined from the main shot or you can get it as part of finding the camera position so there are a variety method methods to do that depending on what you have and know the important point is that the coordinate system for the second shot must exactly match that of the first so the main possibilities are to use the from seed points solving mode with some known XYZ positions you can do that even though you're working just from a single frame you look for common features in each of those shots the original shot and the clean plate alternatively you can use pin mesh in camera pinning mode if you have some mash that's inserted in the shot you can use that as a basis to do your lineup or possibly you could use alignment lines as well though that's not as accurate so really the from seed points method is the best method because you do want accuracy and of course if they're clean plate you know is really from the main shot then you want to just go ahead and use the main solve and the prepare for clean plate script as the best choice one final warning when you do work from a single clean plate there won't be noise in the inserted areas since they all come from the same single image you may need to add matching noise into just the right areas normally you'll write the output as a sequence with an alpha channel so you can composite over the shot yourself you can use the alpha channel of the insert to control where the added noise goes in order to avoid giving the insert away when you use the entire shot as a source that's not an issue thanks for watching