CPSC 815
With Dr. Davis, Fall 04
Project 1: compositing stills
PHASE 1: Two Live composited Images
For this task I chose to composite two images, a close up of my ever faithful artists mannequin (and really cool action figure) Captain America, and a cozy little scene from the DPA lab in McAdams Hall. (Fig. 1) The Concept here is to make the small seem large, and make an object "live" in a scene where it would normally not appear. This phase was also about my learning quickpaint, which is what I used exclusively to make the cap's alpha channel, as well as the shadows underneath him. The Shake Tree I used has a quickpaint node directly downstream from the main image. The quickpaint node with only one input serves as an outside node if you use the reveal brush, effectively allowing you to paint an alpha channel in real time, erasing away the unwanted background as you go. The shadows were added in a second quickpaint node using the paintbrush tool at a low opacity. This node was downstream from the DPA background node(capbghigh000002), and thus the shadows were drawn behind the captain. A few color correction, blur, and 2d transformation nodes later, and the cap seems to be having a conference with Manish, Rupali, and my man Stan. Here is the result:
Avengers Assemble, and gather round the Linux box.
Problems Encountered:
QUICKpaint is most decidedly NOT. On a decent sized image, the Quickpaint node lags like a mo-fro unless you use the lowest proxy setting, which definistrates any attempt at precision work. This is obvious when you look at the alpha channel- you can "get by" with it, but there's got to be a faster way. Also the qp's alpha channel created a grey halo around the cap that I just couldn't get rid of- luckily the scene is mostly grey anyway.
PHASE 2: Blue-screened Foreground on Live Background Image
This phase was definitely the most time consuming, but it was also the most rewarding, as I learned the most about Shake with this exercise. (Actually I did this one first, and probably took way too much time on it- Hope it shows!) The main objective of this Phase was to learn color keying to create a matte and extract unwanted background into a foreground images alpha channel (although, by the time I was done I also used a rotoshape extraction and included two cg elements with their own alpha channels). I used chomakey nodes to do this. I was told that primatte was better by far and I believe it, but it also looked complicated and I had no time to learn it and finish the project, so I went with the KISS principle. I shot pictures of myself , Rachel and Yu-ting against a blue screen and extractent them with chomakey, using quickshape nodes for garbage mattes. The hat and the eyeballs were the cg and quickshape oddballs spoken of previoulsly. I color corrected each image with color correction nodes of many and various kinds, and the result is two girls being chased by a cloning experiment gone wrong. A monster, or should I say, a MANster- a monster made of men. Once again, here are the alpha channels and Node tree., and here is the final result:
With a puposeful grimace and a terrible scowl, he pulls the spitting high tension wires down....
Problems Encountered:
Once again, large image sizes REALLY.....BOG.....SHAKE......DOWN. The chroma key took a lot of fiddling to get it right, but I was impressed with the sensetivity this node was capable of. But there's no substitute for a good photo to start with. Rachels and Yu-tings alpha channels were almost un-extractable due to blurriness and generally poor photo quality- my fault! Color correction is another example of this. I wanted a technicolor look to the background (a-la movie poster) and it was really hard to choke that out of a picture taken on an overcast day. Other than losing a lot of elbow grease, no other problems here.
PHASE 3: CG Element on Live Background Image
For this project I took the turtle character from our 860 project "Space Cat" and have him take a shower in my bathroom at home. This phase was the most fun b/c the cg element comes with its own alpha, and matte extraction it kept to a minimum leaving me free to mess with the displace and blur nodes to make the turtle appear to be behind the shower door. Another fun challenge was matching the characters pose and lighting in Maya to the original scene. To do this I used the "Import Background" feature in maya to create a background to build against. when creating lights, it is then easy to eyedrop-sample a light color from the BG image. Once again I used Quickpaint to make some shadows for the shell. Here is the alpha channel and shake node tree, and here is the result:
Eeeeeeeeek!
Problems Encountered:
Didn't much like the little "node puzzle game" I had to play to figure out what should go on top of what, and what should knock out what else. Took way too much time. In my opinion, a layer based solution is more elegant for single images. See below...
PHASE 4: Live Element on CG Background Image
Up till know I've been a good little boy and not even touched Photoshop. Despite great temptation to fall back on the program I am familiar with I have stuck with Shake and only shake in order that I may learn this King of film compositing programs. Film being the operative word here. I am sure I will discover that shake rules the roost when editing video at smaller sizes, but for doing single images I will continue to use PS. Compared to photoshop Shake is woefully clumsy and slow at manipulating large single images.So much so that I ran out of time and was forced to fall back on old reliable. What took me about a day to do in shake I accomplished in about two hours in Photoshop, as seen below. Apparrently Stans meeting with the cap was about a mission to cyberspace, in which for whatever reason we find our man Stan running from one of those simple yet ominous denizens of computer security, a recognizer (anyone here seen Tron?) The recognizer was modeled by myself in Maya and rendered out in vector mode for that Tron-ish look (from movie). Of Alpha Channels and shake node trees there are none but here is the layer set-up I used in Photo Shop. Nice and Simple. I created all these effects in much the same way I would have In shake, but without the move..... and wait.......move......and wait......and here's the result:
Staaaan on the run....Stan on the run..
Problems Encountered:
A little difficulty figuring out how to render out wireframe on solid with Maya's vector renderer. Documentation is not great...
Well that's it for now ! See you next project!