All language subtitles for 04. Camera tracking the liveaction plate

in this lesson

we will camera track our live action plate

to begin compositing in our CG mushroom cloud

so the first step that we need to do

is we're going to actually camera track

so at this point

the camera tracking will be to match

move the to

ultimately to match

move our mushroom cloud to the actual camera

handheld footage that's going on

in our background plate

where it's kind of moving around

shaking etcetera

now obviously

we discussed this in one of the earlier lessons

about how we are expecting

potentially

there to be some issues

let me just switch over to the original plate there

I'm expecting some issues to potentially arise

when the whip pan occurs

from the screen left

moving to the screen right

as well as towards the end

when the camera drops on its side

um those are the two areas I'm foreseeing

that will be issues with our camera tracking

but we won't find out until we do it

so let's just jump right in and see what happens

so if we full screen our no graph here

I'm going to hit the tab key

and I'm going to begin typing in camera

and you're going to see

Camera Tracker is one of the options that comes up

so let's just select that camera tracker

drop it right in

right there

let's connect it to our actual background plate

and go out of the no graph view

and what I'm going to do is

the first step we actually have to do

is obviously

run the track

so we're going to set a few

few items here

before we do that

the first step

I foresee is

obviously this is

this is a free camera

so what that means is there's

there's free range on the motion

uh the lens distortion

there is uh

what what we're gonna assume is

we don't know what the lens is

instead of saying

there's no lens distortion

so let's just select

unknown lens

and then the focal length

also unknown constant

that's perfectly fine

cause I think I'm going to run under the Assumption

that there was no actual variants in

in the focal length

but it was locked off

but obviously

we don't know what that constant is

and then finally

the filmback size

so for the filmback size

typically actually it'll

it'll tell you right here

if you mouse over and let it sit

if you set the focal length to unknown

uh it will actually

you don't need to know the filmback size

because it will actually take

take it based upon its estimated focal length

but in this case

we do know the focal length

it's a it's a smaller sensor

so it would be a 13.2

by 8.8 millimeter uh

image sensor

for this plate

and then what we're going to do finally

let's just drag this out a little bit

I'm going to go over to our settings

and we're going to just take a quick peek at

the settings here

so our number of features

these are the number of tracking features

that it's going to pull from every single frame

150 the default is fine for now

we'll just stick with most of these defaults in fact

uh the only thing that I foresee

we might need to drop down is the keyframe spacing

this is typically this is

this is what you use to uh

when you're solving the camera track

uh that's the neck

that's step 2

basically you first have to track

and then it will solve based upon that track

and when it solves

you will find that you might need to adjust and

or lower the keyframe spacing number now

but at the moment

let's just stick with the default in those settings

and see what happens

so let's hit that track button

I'm going to hit track

that's going to bring up

it's going to start

it's thinking about it

and you can see right here

if I move the progress bar

and we wanna see that viewer

if I just zoom in a little bit

it's kind of a little stuttery

but you see these little points

that it's starting to track based upon

uh various features that it's pulling from the plate

that's good

and I'm just gonna actually

let's full screen this

then you can kind of see what's going on

I'm gonna move this progress bar

down here for the moment

but you can see what's going on

so what's gonna happen in this uh in this

in the tracking

is it's going to

it started at frame one

it's going to work its way forward

through the entire timeline to frame 7 85

then it's going to track in reverse

and it's actually gonna work its way from 7:00 85

back to frame one

at that point

you will have your track

at that point

then we can work on the solve

and see what happens

so as you can see

the progress

time to go is going to be nine minutes

gonna be a little wise while to go

so I'm going to actually

just let that cook for a moment

I'm gonna hit pause on the

on the recording

cause I assume you don't wanna just watch this track

it's not gonna really help you in any way

and we'll come back in just a moment

and we'll continue where

where this camera tracker picks up

as soon as it finishes tracking this shot

okay so we're back here uh

I just wanted to actually pick up for just a moment

for you to see uh

at the very end here

what's going to happen

I had just mentioned it

but just for you to see

you're going to see

that the tracking node is gonna hit the end

and now ping pong's back in reverse

and it's gonna pick up and continue

tracking in reverse

back to frame one

so we're basically at this point

actually the progress bar tells it to you right there

we're halfway done 50%

and now it's working its way back

uh I do expect

again like I mentioned

that this ending sequence

to have some issues right there where the

when the camera drops down

but we'll find out when we go to solve

at the moment

I'm gonna again hit that pause button

but you can keep watching uh

on your end

as you run the

as you're running the tracking node

and we'll pick up

after we get the final camera tracker data

okay so we're back here

it looks like we are just about to have

our camera tracking data finished

and there we go

so now if I run the mouse through here

you're going to see the actual tracks

and at the moment

we don't know which ones are good or not

because we haven't actually solved for it

but you can see the various lines

and the various points

at which each of the tracking points are picking up

you can actually mouse over

and it'll tell you your track lengths

you can see if I run the mouse for that 6 91

you know anyway that

but there's

there's a lot of data that is useful

that can be pulled from here

uh and obviously

in this whole middle section

again like I mentioned

it seems like we should be just fine

uh it's just the beginning

and that we're gonna find out a moment

so if we go out at full screen mode

and at this point

let us try solving

so if we go back to frame 1 and hit solve

and let's see what happens

it's going to uh

it doesn't take very long for it to give you results

whether or not it is a good solve or not

so we'll just sit here and wait a moment

and if it airs

it'll throw an air right about now

there we go

alright so what we were expecting is

what happened then

it'll say fail to calculate all key frames for the shot

try reducing the key frame spacing

or manually define the reference frame for the solve

in the settings tab

so what this basically means is

let me just go over to settings tab for you to see

um this is actually what I mentioned just a moment ago

the keyframe spacing

it's going to control the number of keyframes that are

being selected

automatically of course

and then are going to be used in the solve

so you can actually set a reference frame where you say

okay this is the reference frame

that I want you to solve based upon

so it's gonna base all of its surrounding frames

upon any of the tracking data

that is on that specific reference frame

so if I go back to full screen here

what you're going to see in the timeline is

you see this blue line

obviously that contates that there are keyframes

so we've solved

uh from frame 38

on out to frame 7:32

so this is actually very similar to

almost identical to

what I was actually kind of expecting to have happened

where you can see here

you see all these Green Point uh

tracking points

uh those are telling you that those are good tracks

those were able to solve

they it didn't have any trouble

so it's able to track

as I just scrub forward

it's able to track

and you can start to see

where it starts to deteriorate as the

as the camera starts to drop

you're losing more and more of those green

uh usable tracks

to the point that

then it breaks

and at that point now

and that's almost exactly what I was expecting

where this basically cuts off that mid and back

mid ground and background space

and you aren't able to pull any tracking date off it

and then if we go to the beginning

what's happening here is

on the Whippan

it basically loses

tracking data as well

as it whips

from the left to the right

now we could go into settings

and we could try

adjusting that uh

keyframe spacing

just for kicks

let's do that

so I'm gonna set that down to

actually just uh

set it down to point o five

and let's see what happens if we uh

go back to frame 1 there

and let's uh

let's try solving again

so let's hit that uh

update solve button

and it's going to just hit okay

and let it process for just a moment here

and what it's going to do is

it's either gonna throw an error

or it's gonna update

in this case we

it's still failing so what I

I'm expecting that to happen in fact

uh I don't think

in fact we would be able to correct

based upon just uh

doing some keyframes

spacing adjustments

uh we could go

and do a few more uh

adjustments

for the camera track

but I think

for the sake of this shot

I think actually

what we have right now

is going to be suitable and usable because uh

if we just go full screen here again

and analyze where the keyframes start

the keyframe starts at frame 37

and you can see this building right here

if you watch that building

right there

as I uh just

uh scrub over

you can see

that building is pretty far off from downtown

downtown is where the mushroom clouds going to be

so I'm not too worried about that

and then obviously

at this end

this is where it'll be a little more of a challenge

because obviously

we wanna maintain that mushroom cloud

as the camera drops

now to do that

though I think we

we might end up

we could go one

of two ways

we could go in

and start to manually adjust our camera

um or we could just do a simple

quick uh kinda

you could say

almost like a quick

kinda cheat

so to speak

and manually adjust

the movement

of that mushroom cloud

on the tracking at the end

which is probably what we'll end up doing

just because

it just adds an extra uh

realm of a challenge

to what we're working on

for the shot

so just to do a quick recap

for this lesson

uh we have discussed

how to camera track

our live action plate

to begin compositing

with our visual effect uh

mushroom cloud

and at this point

we're gonna take a quick break

and we'll come back

and we'll begin

roughing in the comp

for the nuclear

mushroom cloud