Battle damage

First of all, I have to change my schedule to Thursday. It is getting harder and harder to write on Wednesday, too much projects to be finished by the middle of the week. As you’ve noticed sometimes I need to skip the week’s entry for the same reason – too much work.

 

Ok, let’s get back to business.  Today I will tell you a little about  post-production phase.

So the final shots finally arrived and  according to your previous execution plan, you can start working on them… not.  First you have to estimate the damage done on the set. Yes, usually most of the shots have many issues, and are made in a simply wrong way. So you have to analyse them frame by frame, and figure out necessary modifications to your original plan.

The next thing you have to take care of is to make sure the shots are color corrected. Remember – corrected, not color graded. This means the colorist evened out the black and white levels, removed improper white balance etc. Don’t try to work on the graded material, as you will never be able to match the colorist’s artistic work on color by eye.

Then you have to make sure the shot you have, matches the offline edit, that the format of files is the one you should use. Working on the 8bit source frames made by editor’s rookie assistant is a waste of time if the 24bit RAW source material is available. Always check your formats and try to work on the best possible. The more information it holds, it’s easier to match the CGI into it. If your shots are to be transferred to the analogue film tape – you just can’t use 8 bit source – you need a float point information on color. But be mindful of the disk space and your computer’s abilities. Sometimes you just don’t need RAW 4K source material if your final image is to be shown on YouTube 720p :)

Ok, let’s assume you’ve got your shot from my previous post – The hero walks into plaza, with blueboxes closing the streets in the background, the villain is taking off and flying away in hovercraft, and there is a big Si-Fi cityscape in the background. There is a camera on the crane movement with a lot of parallax change during the shot.  How to bite that shot? What’s need to be done to accomplish the director’s vision?

Let’s assume you have all the assets created for you – the villain’s hovercraft is 3d modeled, the matte painting of the city is done, and you have all the documentation from the set on your disc ready to use. The shot is in proper format, it is color corrected and checked for it’s duration against the offline edit. The edit can’t change at this point! Not a single frame can be changed, or you will need to do a lots of work over again. So make sure everybody knows and agrees to that.

This is a time to track the camera movement in 3D. That’s what I usually do first, with shots like this. This is where your on set notes comes in handy. The more information you put into the tracking software, the more precise is the result. The wide lens crane shots are usually easy to track. Remember to mask out every moving object (like our hero walking) before you track it – it usually helps a lot. But this days tracking software is extremely efficient – so most of the time you will have good results quite fast. Check your scale – put some test object into the scene, try to match their height against any object you measured on the set. You are looking for very precise match. Watch your scene from other angles in 3d view-ports in your software – is the path of the camera matches the one you had on the set? The software sometimes flips out the movement – it looks good from the camera point of view but in fact it does not match the real movement and you will have very weird results during working within 3d software.

Next you have to put it into 3D software. I am a 3ds Max user so I will reference to that from time to time – but from my experience this apply to any 3d commercial software on the market like XSI or Maya.  When you imported your solution, it is a good practice to spend some time on scaling it and matching your 3d environment – as it is rarely the case you can use it as it is right from the imported data. Don’t mess with the camera itself – move and scale all the imported data at once – the points and the camera as one object. Check it every time you change something – does it match the source material? Is the movement EXACTLY as in the tracking software?

Now you can recreate the on the set scenery in you 3d soft. It’s rarely necessary to do a detailed copy of everything. At this point you will use simple box proxies for buildings, trees, and what is most important – the CGI hovercraft. Take your measurements from the set and try to get the overall scale of your 3d scene. If everything matches you are good to jump to the animation phase. Remember that you don’t need to match every CGI element in one scene. 3d Tracks are rarely that good  - so you can prepare different one for the hovercraft and different one for the streets or the background. But let’s assume you matched the scene good enough to do it in one 3d scene – it’s still means you will need to render every piece separately – just to have a control over every element in composition.

When you start animating, it is best to use simple proxy models at the beginning. You can use primitives for that, but if you work with directors without experience in 3d creation – they tend to force you to show them final model on every preview. Don’t let them do that! You have to have the comfort on animating with simple objects for smooth display  while you work. But having a good looking proxy 3d model is a key to make them happy.

When animating flying objects – which is particularly easy – the key to success is a “feeling” of weight and mass. Many times I’ve seen WWII bombers flying like jetfighters or heavy SI-FI hovercrafts flying like RC helicopters. Many times directors or inexperienced supervisors force you  to “make them go faster!”. That’s usually means they feel something is wrong with the animation, but the speed is rarely the case. It’s the mass and weight “feel” your animation is lacking. In my opinion – it is better to stick to the real life speed. That’s why I care of the scale so much. I can just check the plane’s typical speed, watch some air shows to compare my 3d results and then show it all to the director. It’s usually enough to convince him. It’s harder with Si-Fi – there is rarely anything to compare with. But try to imagine the mass of the vehicle, it’s type of engines, watch some real life vehicles with similar properties – like Hurricane jet, or light helicopters. The real life reference is the key to good animation.

When you work on the animation with directors or supervisors – be prepared to make fast previews, and make a lots of them. Make adjustments on the fly. Do the main vehicle movements animation as long as your client is fully satisfied with it. Then, only after his approval (have it on paper or in your email just for sure :) ) – move to another step: the extra animations.

The trick to bring life and detail to your animation is all those extra parts and bonus movement you can add. In our case, our hovercraft should have flaps, landing gear, antennas or even the villain pilot moving during take off. It is most important when we see the vehicle for the first time and the audience is focused on that. Don’t overdo it, usually small movements are enough – the ones that are noticed on the subconscious level.

Ok, next week we will talk about interaction with the on set environment. See you.

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