5 Replies Latest reply on Oct 9, 2009 12:28 AM by Mylenium

    Tracking challenge, change autumn to spring!

    ingvarai Level 1

      I am making a movie! In a cene, a car arrives, unfortunately I had to shoot it in August, the drama takes place in May. This is in Norway, and spring is very different from autumn. I want to replace the foreground fields with a still photo that gives the May feeling, the spring feeling.

       

      Here is how it looks in spring:

       

      spring.png 

       

      For tracking, I have Mocha for AE, version 2 (with shapes support) and I have SynthEyes.

      How would you approach this task? There is also anothe interesting task here, the front wheel has this "white thing", I don't know the English word for it, the rear wheel not. This I successfully managed to fix, using two comps, stabilizing the fron wheel, using a mask (alpha layer) , then tracking the rear wheel and put the fron wheel above it :-) Very realistic. By offsetting it in time, it became perfect. After Effects is great.

      Now - for this challenge, I need some ideas and hints on how to approach it!

       

      ingvarai

        • 1. Re: Tracking challenge, change autumn to spring!
          Mylenium Most Valuable Participant
          There is also anothe interesting task here, the front wheel has this "white thing", I don't know the English word for it, the rear wheel not.

           

          This should be the wheel cap... Anyway, to the problem at hand: Have you considered, that most people do not really know what spring in Norway looks like? based on that, you should have much more room to play. The biggest issue I personally see is that there are some thistles and dry grasses in the foreground. Those should definitely be painted out. the rest could be perfectly done with a few simple color corrections. Yes, the grass is long, but do we know the Norwegians trim it in autumn? I really think it's much easier than you think.

           

          Mylenium

          • 2. Re: Tracking challenge, change autumn to spring!
            ingvarai Level 1

            Thanks a lot Mylenium,

             

            I am glad to get a response to this question, indeed. First, to the actual movie, there are several scenes shot in May on this location, so the different surroundings will be noticeable.

             

            But what I want to discuss, is the techniques  in general, to solve such challenges. This scene actually would be a good source for a video tutorial, and solving the missing wheel cap is one of the tasks that could be explained in such a tutorial. It is rather exciting to see, the front wheel cap becomes the rear wheel cap and by offsetting the front wheel composition in time, it rolls behind the grasses right where it should, very convincing.

             

            Now - to the fields, I wonder how I can make a still photo in Photoshop of the field like it looks in May, not August, and track the main movie and have the fields still photo follow, and possibly scale as the camera zooms out. Regardless of to what extent people may observe this at all, I am interested in the challenge, technically seen, I want to learn as much as possible.

            Again - thanks a lot for responding to this, it is much appreciated! When this has been solved, I will reward the AE community with a video tutor.

            • 3. Re: Tracking challenge, change autumn to spring!
              Mylenium Most Valuable Participant

              Even if you want to go that route, you'd only concern yourself with teh foreground in that specific shot - pine trees look pretty much the same at any time of the year. You'd cut out the fields, clean up the background and use it as a static image most likely. You would also keep the road and blend it in with thin lines of grass remaining nad feathered edges. For the foreground you'd then paint a clean overlay in PS based on your other May footage. Shoulkd be easy enough, as except for the people who were there on the day, nobody knows what it realyl looked like so you can use whatever clone sources you deem suitable. I'm not sure whether you would actually use any tracking in this shot. For doing so, you'd have to latch onto the background, but then you'd still be left with the parallax problem, since it is a pan, not a move. The foreground moves a lot faster than the BG. You'd probably simply animate it by hand.

               

              Mylenium

              • 4. Re: Tracking challenge, change autumn to spring!
                ingvarai Level 1

                Thanks for your interest in my project and your advice and your time! Yes, I will make the foreground in PS.

                I'm not sure whether you would actually use any tracking in this shot. For doing so, you'd have to latch onto the background, but then you'd still be left with the parallax problem, since it is a pan, not a move. The foreground moves a lot faster than the BG. You'd probably simply animate it by hand.

                I don't easily give up ;-) I will definitely see how I can do it, using some kind of tracking. I have SynthEyes, which is very advanced and should be suited for this task. The problem, as I have understood it, is that it has been shot from a camera mounted on a tripod. A moving camera is supposed to be much better for this kind of software (SynthEyes) to find out how things move in the picture, especially perspective.

                I have tried what you mention, and it somehow works. I use a very loooong image of the foreground field, it moves along, yes, but it does not look anywhere near realistic, not at all. I used Mocha version 2 for this, by the way. In AE, I do not know how to use trackers, because any starting point will get off-screen, and any end point will not be visible at the beginning of the movie. Mocha does not have this problem.

                 

                I find this topic very interesting! I will definitely keep you updated on my progress.

                • 5. Re: Tracking challenge, change autumn to spring!
                  Mylenium Most Valuable Participant

                  In AE you would reverse your workflow. You'd first extend the plates, then track the large items, then use some simple expressions to transform the values back to comp space. Anyway, if you have Syntheyes and mochaAE v2, just stick with those tools. they beat AE's internal tracker flat hand any time. In SynthEyes it might be a good idea to create a row of dummy objects along the projection axis that get exported as Nulls to AE. This might help matching the orientation and speed of any work you do in AE.

                   

                  Mylenium

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