• Mike

MA Perfecting The Look: Kicking Off the Final Comp

(⌐■_■) hey folks!

The project is now underway as I juggle between this assignment and a myriad of other things going on, but I got some updating to do so - in the words of the Black Eyed Peas - let's get it started!


The Chosen Theme

In the end, I decided to go for the serene nature scene over the sci-fi one. It seemed like a lot of people might be doing something similar - as in, using the same sorts of assets - so I wanted it to be something at least somewhat different to the crowd. Plus, it also means less things to worry about animating (well, dealing with animations to be exact). Helps reduce the risk of something going wrong, right? Plus plus, the cherry blossom tree gave me some really nice Japan vibes, and my god I miss Japan like crazy...so its a little nod to me wishing to go back and see more of the country!

Anyway, that's the plan, so I have my chosen footage ready to go!


Undistorting the Lens

The first thing I need to do is to undistort the lens within the footage. Since I am using one of the clips provided by the module team, I (thankfully) also get additional helpful information like the focal length of the lens that was used. The footage used a 24mm lens so I can use the provided grid that matches this focal length:

Oh, and I have set up the project settings as well so that I am working in Full HD 1080 format and have my python scripts all set up too!

Anyhow, I need to ensure this grid is also set to the correct format by using a reformat node to set the output to 1920x1080. To help make the grid look clearer, I also added in a Grade and Sharpen node so that it looks like this:

Now, just like before, I need to connect in a LensDistortion node and Detect the grid, which looks...not that great to be frank.

So, after fixing up all the features, I got it to a state where it was more-or-less all good to go. The downside is that, for whatever reason, all the red connections would never turn green, no matter how many times I deleted and added in new ones. Eventually, I decided to cut my losses and accept that I wouldn't be able to get these working. This was then written out with the Mode set to STMap. Oh - and this is exported out as an exr file!

To top it off, here is what the final node tree for this segment looks like:


Undistorting the Footage

Now that the lens is all undistorted, the footage needs to get undistorted too for setting up the camera tracking and exporting that into Maya. After bringing in the footage and exr file, I can connect them up to a STMap node, with the source connected to the footage and the STMap connecting to the exr file of the previously done grid. To make sure the STMap is working across all the frames of the footage, I can plug in a retime node and enable the input and output ranges to customise them. The important one here is the output range which is going to be set to match the length of the clip - starting from frame 0 and ending on frame 680. You can see the before and after for the footage below (although the difference is very subtle in images):

Now, because this process is effectively pushing the data beyond the boundary box, I need to add in a reformat node again but create a custom output format. This just needs to be slightly bigger than the Full HD format, so I've added 10 pixels to both axis, making it 1930x1090. The resize type here will be set to "none" with the "black outside" enabled.

This makes everything ready for doing the camera tracking now and that will wrap up the first stage in Nuke! Here's what the node tree for this segment looks like:


Camera Tracking and Exporting Data

The process here is exactly the same as before where I wrote up about doing 3D tracking with some minor tweaks here and there. The first tweak is making sure my CameraTracker node is correctly set up, since I know all the details such as the focal length and what typed of camera was used to capture the footage:

In the Settings tab, I started off with the usual 800 features but later felt that I required more of them to generate enough usable tracks in the scene, so bumped this number up to 1000 as my starting point. The number decreased quite considerably by the time I was done with Solving the tracks and reducing the Solve Error value.

After getting to a point that I felt was satisfying, I added in a scale into the scene so that when I make my ground plane, it would be scaled to a real-world value. Going into the Scene tab, I created a new entry that examined a pair of points that aligned along one of the steps for the staircase in the scene. Luckily, this info was also available, so I knew the distance was about 7 inches. Converting this into centimeters I am told will help later when I export this into Maya, since Maya uses cm by default, so I did that!

With this done, I brought in a ScanlineRenderer node and connected up all the corresponding points so that I could create a ground plane using a much larger number of tracks than I had done in the past. This was a result of doing some online research to see how to get the best out of the ground plane here and I saw quite a few videos where people used more tracks, regardless of what their error values were. It also seemed like a better idea since I could get a more accurate ground plane from doing it this way instead of being picky about the tracks I used.

This is how it turned out in the end:

Okay, so I know I said ground plane and there currently is no plane...buuuut I can now add in a Card node and start messing around with it to actually make a ground plane! To help actually see it, I plugged in a Checkerboard node and aimed to align one edge of the plane with the wall opposite the potted plant. This would act as my workspace for when I bring in my assets into Maya, since trying to cover the whole brick floor would be a bit too tedious I felt. I also knew I would be using the corner area for the position for my tree and would be building around that, so that's another reason!

After messing around with the alignment and being a bit of a perfectionist about it, this is the result:

Ta-daaaa! Its now all ready for exporting and ready to be used in Maya! I wrote out everything in the scene except for lights, since none had been added, and ended up with the following node graph at the end:


Closing Thoughts

Okay, so we're getting somewhere! I think the most unnerving part was handling the tracks, since it felt like I was losing quite a lot of them in exchange for an ideal Solve Error value, which made the 3D view of the tracks seem much less reflective of the scene. I haven't yet seen anything to suggest that this is going to be problematic inside Maya, but I am reaaally hoping it doesn't come back to bite me!

I've also been using this Backdrop node a lot to keep segments of my nodes organised and easy to make sense of. Oh and I've been using versions to have a clear history (and backups) of my Nuke workflow, which I plan to continue doing inside Maya. There are currently 2 versions of my Nuke project at present, so I suspect I will have a few more by the end! Since I don't remember much about Maya, it might be another couple of weeks before I post something again while I remind myself of all the shortcut keys for navigating the software.

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