Over the weekend I posted the above image of a Viper from the 1979 version of Battlestar Galactica; as most people are aware, when that show was produced there was no such thing as CGI, so all of the visual effects were created “old school,” meaning the Vipers were actual, physical models, photographed with real lights and a real camera. Thirty years later, visual effects on the new BSG are created entirely with computers, but, despite all this fancy new technology, the goal of most artists is to still have it look like good old-fashioned miniatures and cameras! Of course, on the new series, there never was a real Viper model, so we have nothing to compare the CGI version with to see if we “got it right.” However, there is plenty of footage of physical Viper models in episodes from the original BSG, so I decided to see just how close I could make a “fake” Viper look like a “real” Viper…
Truth be told, this whole saga began not as an experiment to see if I could fool people into thinking a CGI Viper was real, but to evaluate the work of a very talented Galactica fan and 3D artist, Derek Smith. Derek (for reasons known only to him), had taken a blood-oath to make the most perfect CGI Viper model humanly possible. In the world of 3D fanboys, the Viper is one of the most common project ships out there; hunt around online and you’ll find dozens of 3D Viper models – some of them suck and some of them are OK, but none of them would ever be confused with “the real thing.”
Derek wanted to confuse the world!
With steel-willed intent, our erstwhile modeler hunted down reference of the original filming miniature, as well as the ’70s model kits from which pieces were cannibalized to make it. Armed with a pair of calipers and a mouse, he painstakingly “translated” every last fuel line and cockpit rivet from the real world into his computer modeling software (Lightwave 3D from Newtek). Derek spent the better part of his free time for over two years putting this thing together, and it was a just few months ago that his friend and mentor, Lee Stringer (CG Supervisor of the new BSG during season one), asked me to take a look at it (click to enlarge):
To be honest, I was initially underwhelmed. I appreciated the fine level of detail and skill that went into building it, but my first thought was “it looks like a really good re-creation of a model kit, not a real Viper.” I didn’t even have the heart to email Derek and tell him, since I knew how much time and effort he put into the work that I was so readily dismissing. I figured I’d take another look at it when I had more time and see if my opinion changed.
It didn’t. I asked Mr. Stringer for guidance. “Lee, what do I tell this guy? He put so much work into this thing and I don’t want to tell him it sucks!” Lee thought for a moment and suggested, “maybe it just needs to be lit properly. Studio lighting is way different that the simple lighting Derek used to just show off the model.”
I was skeptical, but I wanted to give the guy with the blood oath the benefit of the doubt, so I fired up Lightwave and loaded the model.
DOWN AND DIRTY
I figured if I was going to see how close it was of a match to the original Viper, I should take a framegrab of one from a DVD – the way we all remember it – and see if I could match the look using Derek’s model and some studio-style lighting (and since I often tell people that lighting is everything, it was time to put my money where my mouth was). So, the first step was to pick a nice shot from the show and position the CG Viper in roughly the same way:
Here is the CG Viper, roughly positioned the same way as the real Viper. No, it’s not a perfect match, but remember – this wasn’t an exercise to perfectly duplicate the original image, just an attempt to see if the CG Viper could at least “hold a candle” to the real miniature. Now let’s get some light on it!
Here it is with the default Lightwave light, called a “distant” light. It has perfectly parallel rays, designed to mimic sunlight. Exactly what you’d want on a spaceship, since it’s flying out in space and lit by the sun! But in this case we’re trying to match the look of a filming miniature, which was lit by a spotlight in a studio and not the sun. So, with a click of the mouse I turned the light into a spotlight and examined the image to find clues as to where the light might have been placed by the guy with long hair and Bee-Gees T-shirt (remember, this was the late 70s)!
The circled areas show the best cues on the model that give away light placement, which was roughly from above and slightly behind the ship. I had the framegrab opened in one window while I positioned the light in Lightwave (using the indispensible preview tool “F-Prime,” I was able to track the movement of the shadow in real time I positioned the light). Once I got it “close enough” I locked the light in place. Now, take a close look at the shadow on the wing, where it meets the engine – see how the complex shape of the shadow is nearly a perfect match for the same shadow on the filming miniature? Now that’s modeling accuracy! I was becoming more and more impressed with Derek’s model. Now that the key light was set, it was time to look at fill.
A few posts back I did a piece about backdrop radiosity, and how it casts a nice, even, studio-like fill light on 3D objects. Since the original BSG used far more fill than the new series, I wanted these areas of the ship to look as good as possible, so I started out by using backdrop radiosity at about 50%. It nicely filled in the areas that the spotlight wasn’t catching, and the wonderful dimensionality you get from radiosity started to make the render look really good. I was just about ready to call it a day and tell Derek his model passed muster, but something about the fill light from the original framegrab caught by eye and told me it wasn’t right. See the yellow circles on the 1979 image? I was catching a hint of speculaity (i.e. shine) on these parts of the ship – something that could only come fr0m another true lightsource . Now the game was afoot!
At this point I decided to go all the way and see if I could reverse engineer and re-create all the natural elements of the 1979 studio. Obviously backdrop radiosity was not in anyone’s toolbelt back then, so I ditched it and added another light to use as my fill source. In most cases, a soft light is used for fill, so I added an “area light” in Lightwave, which does a good job at mimicking soft shadows. Using the subtle spec highlights as my guide, I moved the light around until I was able to catch those same highlights on the CG model. Success! But wait, something still seemed amiss… if you look at the circles here, you can see how the nose goes a bit dark in the real-world image. Why?
Because the light from real light bulbs diminish as it gets further from the source! Naturally, the part of the model closest to the light will be brightest, so I added a falloff to the CG fill (in the world of computers, lights are perfect – meaning even illumination all the way to infinity – unless you tell it otherwise). Ah, that’s more like it! Just that one little change made the model look much more like it was in a studio. After I finished setting the fill, I noticed that little extra shadow you see circled here – my confirmation that the light was properly placed. This whole process made me feel like part of the CSI team, using little bits and pieces of forensic evidence to recreate the scene of the crime…
Combine the key and fill and viola! We now have a very close CGI match for the original 1979 studio lighting. After I spent a few minutes patting myself on the back, I decided to take things a little further and see what it would take to actually duplicate the look of the entire picture!
First up was the starfield. I started out with a very natural backdrop, similar to the starfield you see on the current Battlestar Galactica. No matter how nice it may look, clearly it’s not even close to the 1979 stars, which were far brighter and larger. So, a few tweaks to Lightwave’s starfield object and particle size later…
That’s more like it! Not a perfect match, but the look and feel is right (mine has a little bit more contrast and variation). Back in 1979, they had to play it safe and overdo it with the stars – between the multiple generations of film they had to go through for the optical printing and the unpredictability of analog TV transmission, if the starfield was too subtle it might have disappeared completely! One last detail to add before we go into post-post production…
By sticking a few lights into the engine nozzles, we simulate the light from the thrusters. Now we’ve got all our bases covered! Even so, it doesn’t take a degree in computer animation to see that our painstakingly re-created Viper still doesn’t match the original. No matter how you slice it, a shiny new CG render is a far cry from an image that was not only created on film, but was spat out as a result of multiple generations, various color timings and, ultimately, DVD compression. The solution? Take our shiny new CG render and drag it through some digital mud.
Ah, that’s more like it! By adding some fake film grain, compression artifacts, a little blur and tint adjustment, we’ve now teleported our ultra-modern 2009 CGI Viper into the distant past, where it can now go out and play with its 1979 cousins and not get beat up for looking like a freak.
Ultimately, this is a textbook example of how making CGI look real is all about fighting perfection. Everything you do in CG is automatically perfect – every box you make, every paint job you give it, every light you set – is flawless. It may be oversimplifying things, but in a nutshell, our job is to constantly identify new ways to degrade that natural beauty: make the line a little jagged, fray the edges of the cloth, scratch up the window, put some smudges on the flashlight or take down that red nose from 255/0/0 to 235/15/20.
It almost always comes down to chiseling away that last little bit of perfection to create a truly perfect image!
Next week we’ll figure out how to pick up girls.