Car VFX with Blender & After Effects

in my recent GTA video I needed a card drive into and out of a garage the car had to be CG as did the garage interior in this video I'll quickly describe the steps I took will focus on this panning shot here but I'll include extra tips for other types of shots at the end the basic steps are as follows shoot your footage track your footage add your models add a shadow catcher set up your lights prepare a render settings render and composite your CG elements step 1 shoot your footage this is as simple as it sounds grab the camera and using your imagination try to film the shot as you see it in your head you might want to do a few passes first moving the camera faster or slower to give yourself more options once you start editing it's a good idea to figure out how big your CG object is going to be beforehand so you know how far back to place the camera it's also a good idea to write down the focal length you shot at as well as other measurements like how high off the ground the camera was or how far it was from your CG subject the more information you record the safer also make sure there are enough things in the shot that can be tracked if there aren't add markers these can be super professional-looking or cheap as heck all that matters is that they do the job step 2 track your footage this is either going to be easy or massive pain in the ass usually it comes down to experience so the more you practice the easier it will get I did the tracking on this shot in After Effects this video from Niko of corridor digital explains the After Effects tracking process I use an add-on called AE to blend available on the blender market to copy my After Effects tracking data and paste it into my blender scene if you want to do the tracking inside blender even Hubert has a video here which you've probably already seen but what if my camera isn't actually moving you say even better you can skip the tracking and either place your 3d camera manually by just guessing where it should be or by using a program like f spy which takes some of the guesswork out of it this is where those measurements you took while shooting come in handy step 3 add models import your models into the scene and make sure everything is the right size if you don't have to animate them great if you do then do that if you're animating in a car you might want to look into blaze Raiders car rig add-on I'm basically a complete noob when it comes to animating but his rig was easy to use produced good results and didn't take long to learn I highly recommend checking it out I'm not paid to say that but I wish I was because I'm broke step 4 add shadow catcher turn your ground plane into a shadow catcher make sure its roughness value matches the ground in your footage also keep in mind that it will show up in reflections so try to match its color as closely as you can you can always camera project your footage for a quick fix CG matter has a great video showing how to do that step 5 setting up lights I like using maps from HDR I Haven I look for one that has similar Sun and shadow qualities in this case I want the Sun to be high enough to match the shadow length in the footage and I want those shadows to be sharp the preview render helps a lot in choosing a good map I'm also looking at the overall colors to make sure they aren't too different from the environment in my footage if necessary you can always add geometry to your scene to block out anything in the map that you don't want showing up quick tip if your renders are noisy when rendering with HDR eyes go into the world tab and set the map resolution to something higher than default like 4096 or 40 97 this will clean up your renders and probably even allow you to use fewer samples I save this value in my default blender scene step 6 render settings and passes if you want you can just render the whole thing in one pass but if you have a more complex scene you may decide to render elements in separate passes to make compositing more flexible in this shot I decided to render a shadow pass and a car pass usually I would also render the garage as a separate pass since that needed more samples to render it to a clean result if the camera wasn't moving I could just render the garage as a single frame to save time this video from Jacob holiday explains how to render passes for VFX with a new blender 2.8 update to save more time while rendering use the border rendering option so you're only rendering the area of the frame which the object appears in I also set the render dimensions to 80% CG renders are always going to be sharper than camera footage so if I'm going to have to blur my passes anyway to get them to match why not just render a little smaller to get the same effect I rendered that 80% then scaled the passes up to 125 percent when I composite it to get them back to the right size step 7 render go do something fun step 8 compositing this is where you see all your hard work pay off use whatever software you want I like using After Effects to composite bring in your renders lay them over the footage scale them up to match the size and voila you're done maybe if you rendered in passes you have a little more flexibility when it comes to tweaking stuff do the shadows look too weak you can duplicate the shadow pass and adjust opacity should they have more of a color cast use a curves or a levels adjustment to change the color from there you can use whatever other compositing tricks you want add a Z depth add some lens flares go nuts bonus tips adding light influencers if your model gets close to something in your footage besides the ground you might need to add a CG stand-in for that physical thing since it would probably either be casting a shadow or bouncing light or both onto your CG model the bigger and closer it is the more important this is to do scans from footage if you didn't get a scan while on location but really wish you had you could try running your footage through photogrammetry software Daniel Hashimoto creator of the action movie kids videos recently demonstrated this technique on his Twitter page give it a shot multiple HDRI maps sometimes it's easier to render with multiple HDR eyes to get the look you wan like when the truck moves from the sunny area to the shaded area instead of trying to deal with a CG tree or any of that crap I decided it was simpler to just render again with a second HDR I that matched the shaded area then blend between the two sets of renders and after effects using a masked solid as a track map there you go that's all it takes now go and try it out put a monster truck in your driveway and post it on Facebook go on show your ex-girlfriend she made the wrong decision [Music]

Channel: Classy Dog Studios

Views: 369,481

Keywords: blender, vfx, car, tracking, rig, after effects

Id: mUpm3x6LWlo

Length: 6min 55sec (415 seconds)

Published: Fri May 01 2020