Learning From 3D Generalist to Compositor by Martin Demovic 9 months ago 16 min read This was the first compositing reel after I graduated vfx online school Compozitive. Thanks this I’ve got my first job in vfx industry at Pixomondo. I spent on the reel almost a year which was the hardest year in my life. It gave me a lots of experiences and confidence to handle the new compositing role in the studio.As I tried to be a compositor I focused whole effort on post production in Nuke. Time to time I used Photoshop and 3ds max to help me with some challenges. As I mentioned earlier I used to be a 3D generalist. This allowed me to use these experiences to make the reel more stand out from the crowd.As I noticed many junior compositors use to have pretty same reels, because for example they graduated on the same vfx school. This is the reason why it is important to put there something different to change the pattern look. Whole showreel consists with materials from the school. I will explain the approach and techniques which I used for every each shot.Shot 01Shot 01When I’ve seen first time this shot with overall view of the Vancouver city shooted by drone I was very excited how nice and impressive the shot looks. At first sight it looks like the best shot for futuristic future look. From school materials I had all rendered CG layers like buildings extensions and ships. Up to me was put it all together with logical order, create my own atmosphere and add something special which will change the school pattern look.ReferencesI started with finding references for overall atmosphere look. I really like the sunset look of the original plate, so I tried to keep it. What I wanted to change was overall different color palette and atmospheric haze as cool element to even more define the depth of the shot.Atmosphere referencesBackground replacementAfter I chose the favorite atmosphere look I start with background replacement. The new sky, add mothership where all crowd ships will fly and little change of mountain shape for better skyline composition. As I had 3D camera and tracking markers for the shot, all elements were projected on the cards at an approximate distances in the scene. To better integrate mountains skyline with the sky I added layered light wrap.PlateBG replacementBuildings extensionsFor the buildings extensions I used pretty different method as I would used to as 3D artist. I would render whole sequence in 3D software and then combine it with the plate. Basically I had one DMP frame of the city and 3D models of all extended buildings from lighter. I imported 3D model of the buildings to Nuke and projected separately on them every building from DMP frame. It was basically as a texture for all those buildings. With these method you can save render time when you have to render it all in 3D. Of course this could be use just when 3D camera doesn’t have a big parallax movement. As DMP has much more details as were on the 3D models I also had to putted in the middle of the every building card where I projected rest of the details from DMP. After all I color integrated those buildings extensions with the plate without any visible connection.3D nuke setup for building extensionsBuilding extensions integrated with plateAtmosphereAs I had selected atmosphere reference I tried to match it in colors and haze. Haze was completely done in Nuke with noise, 3D models and cards. I used 3D scene from previous step and putted there additional cards with represented rest of the all buildings. As I had the 3D model only for extended parts of the buildings I had to prepare also rest of the buildings.As always I used cards and roto masks for every missing building or part of the city which could have impact on depth of the atmospheric haze. For the variation and movement of the haze I used animated noise which I putted on few cards in the space between the buildings. With deep node I combined all noise cards together as a seamless atmosphere, which I colored and integrated with the sequence. Maybe it sounds a bit complicated and it was little. But with this method I simulated haze without any needs to go outside of the Nuke and use some special fluid software.Rendered atmosphere from NukeIntegrated atmosphere with plateCG ships integrationI already mentioned that all CG ships were provided to me by school and then my work was pretty straight forward. As it was rendered in Arnold the naming of the layers was different as I was used to work from Vray. I took all single channel elements for master and crowd ships and combine them in logical order to get best result. Since the ships were rendered without masks for the buildings I used rendered deep layers to created holdout masks in Nuke.CG ship rendered passes Particles trails and engineAs the project was approaching to the end I focused to create details as a wing trails, engine tail and head distortion. All of these elements were created in Nuke, even when for me could be easier to created them in some 3D software. But my goal was to learn Nuke as much as it was possible. As I mentioned I used nuke particle system to create wing trails and with the same setup also made engine tail. For heat distortion I used also particles and idistort where you can deforming and blurring plate by these particles as UV channels. Then I controlled length and amount of the heat distortion by depth pass which I had from rendered particles.Raw colored particlesIntegrated particlesFinal touchesAfter many iterations, feedbacks and hours spent on the shot I finally got to the end. I made final touches as a color corrections, added our favorite lens flares, camera shake, camera distortion and grain.Final resultHonestly I can say that this shot was hardest and most complex shot which I ever did so far and I’m very proud on it.Shot 02 and 03Shot 02 and 03These two shots were the parts of the 6 shots sequence Gotham project shooted in Vancouver and provided by the school. As I’m a big fan of Batman movies I liked these shots from beginning and seen there a big potential. On this small school project I had a chance to used my 3D skills to help remodel the Batmobile, do the simple rigging and animation of this vehicle. As I wanted to focus on compositing part of the project I will describe just this process of creation.Remodeled parts and simple car rigReferencesAs always I started with finding a references of the mood and atmosphere. On internet you can find many references of the Gotham streets so it wasn’t hard to find an inspiration. I wanted to keep the darkness of the original plate with little color change and add more depth atmosphere with haze, fire and smokes.Reference imagesStreet preparationI wanted to bring more life and movements to the street which will make better atmosphere. I started with add smokes elements to the walls and road. As I didn’t have a many of these elements I tried to flip and time offset them to get more variations. Then I add some street signs, neons, wall paintings and etc. all with projection on cards. One of the biggest challenge here was realistically integrated fire in barrel and as always I wanted to make it in Nuke. Second challenge was reduced water puddles. This helped me to avoid create splash interactions with vehicle, which could be a bit tricky to do that realistically. For removal I used camera projection on the cards where I used several clean plates and blend them when the camera went forward. Like I mentioned few times I tried to bring models directly to nuke 3D space and work there with them. This is sometime challenge, but learned me a lot to be more efficient.Shot 02 plateShot 02 street elementsShot 03 plateShot 03 street elementsCG BatmobileAs probably most of the compositors I also really looked forward to start play with CG layers and it was finally here. In this case I probably used all of them to get final look. Like on previous shot I used single channel elements to combine them to final look. Then used util elements as a position and normal pass to help me with relighting. As I added fire and in the plate were some street lights I had to relight the vehicle to match the plate. I used position pass to create a point cloud where I wanted to know specific position of the vehicle model in the nuke 3D space. Base on this I putted point lights to simulate real light conditions. Then I used relight node in Nuke with position and normal pass.Shot 02 Batmobile render passesShot 03 Batmobile render passesParticles engineVery similar way as in previous shot I made engine tails in this case. I used animated axis of the engine position and connected onto it particles to get a base layer. After that I used motion blur, glows, some additional blurs and color correction to get a look as I had on the reference.Raw colored particlesIntegrated particlesStreet modelAs I had a plan to add atmosphere base on the street model I had to create very simple model of that. I used nuke model builder to create simple geometry which represent most of the objects on the plate. I had a two intentions how to use this model, first was for build the atmosphere and second to use it for light interactions. I created atmosphere similar way as for previous project. So I putted few cards into the space with animated noise and with deep expression I blend them together. For light interactions I used same model, on animated axis I linked two spotlights as a front vehicle lights and back point light as an engine. From this setup I got additional lights pass which I used as a mask to grade the plate. Last thing which I wanted to mention are faked reflections on the ground from Batmobile. It was pretty easy to do, I just used Batmobile render, flop him and moved to the position which it looks like reflection. Then with 2D track I matched movement with the original Batmobile and used a mask of the water puddles where reflections are visible just on these highly reflected areas. These small details really help to get the shot to another level.Atmosphere haze based on the simple model and animated noiseFinal touchesTime for final color corrections, lens flares, lens dirt, distortion and grain which always help the shot get real and nicer look.Final resultsOn these two Gotham projects I learned really lot, how to more use nuke 3D space, relight rendered CG model and integration elements to plate. In general I could say that after every finished project I felt more and more compositor.Shot 04Shot 04This shot at first sight doesn’t look complicated because it is static camera without any big additional effects. It wasn’t that easy as I thought at beginning, because a main goal was to invisible integrated 2 CG cars. This is always challenge on every shot and also create my first long roto mask of the guy almost for whole sequence. Additional goals were sky replacement, add elements as building windows interiors and neon logos to made a city more vibrant at later evening time. From the school I had also DMP image for whole city skyline extension. As it was really hard to integrate so many buildings correctly I changed my plan to use it.ReferencesIn this case as I tried to find a references for later evening sky, city skyline and windows interiors. As for the CG cars I had references directly on the plate, so from this point of view I saved the time.Reference imagesSky replacementAs I mentioned camera was static so it was pretty easy to create roto mask for whole skyline. Things I had to fight a little with were bright edges around the city and moving traffic cables. For edges I used edge extensions, edge blur and local edge grade masks to reduced brightness. For traffic cables I used animated spline shapes.PlateSky replacementCG cars integrationI started with classic single channel render passes composition and tried to match surrounded cars look. As I had many render passes it really help me to modify many parameters to get best result. Separate passes I had shadows under cars and contact lights on the road. These two layers I animated separately as the situation required. Biggest challenge here was create real front lights as it was crucial animated element to matched look of the real cars. I spent many hours to get proper look to use several glows, glints, god rays and grades. Special problem was on the edges when the guy pass through them where it cost very strong light wrap to him.CG cars render passesDMP windows interiors and neon logosTo get more vibrant look at evening I putted randomly on the buildings windows interiors and neon logos. As it was static shot I just easily marge it on the top of the background.DMP elementsFinal touchesAgain at the end I added last color corrections, grain, glows, distortion and lens dirt.Final resultAs it maybe doesn’t look at the end I spent on this shot tens of hours to get the look right. But spent hours are always balanced with knowledge which I get from it.Shot 05Shot 05This is classic shot which you can get in every vfx studio in the world. Green screen separation shortly keying is also the basic knowledge of every compositor. Honestly I can say that this was almost my first green screen shot which I ever did and as always big challenge to get it right. As I had lot of theoretical knowledge from the course of how to proceed I used this shot as a test to tried the all keying techniques which I know.KeyingI’m not to going through all the techniques which I tried to used for this shot, but just describe the final ones which worked for me. As maybe all knows that keying should be consist with the core matte and edge matte for the details. Of course this is very general description where we have to counting with many additional mattes to fix local areas which always appears. For core matte I used Primatte keyer which provide very rough mask called also inside or outside garbage mask. This removed most of the holes inside the key or noise on outside. For an edge matte I used combination of IBK keyer and Keylight which are the best for details. As I mentioned this few techniques made for me 90% of the work. The important rest I had to manage with combination of other techniques as edge erode, edge blur, roto mask, grades etc.PlateAlpha matteDespill and edge fixDespill as many people knows is removing green or blue color spill from plate which was caused by green or blue screen environment on the set. In this case I used Keylight despill, but as always there are many techniques which you can use to fix it. Last but not least I have to mention edge fix which is always part of the keying. It is due a despill which will change the original color (green or blue) on edges to different one. Mostly it is problem with dark or bright edges on replaced background which could be fixed by some edge extensions, edge grading or eroding.Rough keyRemoved green spill and edge fixBackground replacement and snow/fog elementsI had an idea at beginning that I wanted to move this shot to the winter atmosphere. I tried to find some nice background of the frozen landscape on style of Golden Compass. When I found it I realized that it looks too boring so i decided to add some snow elements to get a nice winter filling. I used nuke particles for background and midground snow and real elements for foreground detail. Fog I created with simple animated noise separately for background and foreground.BG and snow/fog elementsSnowflakesAs every shot should be a challenge in the process of learning I had one in front of me. I have got a feedback when snowing so much main actor should have on her back, shoulders and hairs some snowflakes. I used for this smart vectors which in this case works almost perfectly. I created snowflakes texture with alpha and on one frame I painted this texture on here body parts. Then I rendered smart vector for whole sequence and used it with ST map node for deforming texture by her movement.Snowflakes texture and integrationFinal touchesAs always here is the time for finish shot with color corrections and optical effects.Final resultThis shot was the perfect test for keying techniques where I had to fight with hair details, many edge fix, snow elements integrations and smart vectors which I used first time here.Shot 06Shot 06Last shot is little specific, because it was done by 16 photos from which I created an animation. Techniques called still camera tracking and using nuke camera track, but instead of sequence it calculate cameras for each photo separately. As a result it generated cameras for each photo and could points of whole scene. It is similar as photogrammetry, but not as that sophisticated. My goal was to create camera from each photo which will be used further for model creation and projection.Reference photosStill camera trackingAs I mentioned I used similar technique as for camera tracking, but I used stills solving. Calculation is similar so it’s try to find similar tracks on each photos and by this creates cameras and point could. You can use also manual tracks to help that automatic solving get more accurate result.Still cameras and point could modelCreate a model with model builderFor model creation process can everybody use different techniques and used also point could model as a reference. For modeling I used model builder, solved camera and photos as a source reference. I tried to build geometry part by part with simple primitives like the cube, card or cylinder. Sometime when the real objects were more complicated I used edit geo node to modify geometry to more complex shapes.Modeling basic geometry with model builderCamera projections and animationAfter I finished 3D model I used it for projecting part of the photos on it through the correct camera. As some parts of the objects on the photos were overlapping each other I had to used more projections for that object or do the clean plate from one camera and project it back. Overall I used 44 projections from 11 cameras which were needed for me. When I finished model and textures from projections I created camera with simple movement. It couldn’t be too big because as all camera projections has limited camera angle where the texture on the model doesn’t look deformed.Camera projectionsFinal touchesTo get more realism into the animated sequence I used motion blur and DOF from rendered velocity and depth pass in nuke scanline render. At the end I added camera distortion, grain and color correction.Final resultThis project was very specific, but it really helps me to understand camera projections and situations where I can use it. Before I couldn’t imagine that it is possible to create animated sequence with using just few photos.ConclusionThis reel project took me almost a year to finish. I realized that the most important thing on the course except knowledge and information was especially good and experienced tutor. He led me, gave me a relevant feedback and experiences which moved me and my work much further as I would be possible do it alone.With this article I wanted to special thanks Vladimir Valovič, his vfx course Compozitive and compositor’s community which he trying to build. Thanks to The Rookies to gave me a opportunity to write this article. Read more posts by this author Martin Demovic I’m digital compositor currently in Pixomondo Stuttgart where I moved after spent several years in 3D generalist role in Slovakia.