All language subtitles for Nuke Compositing for 3D Artists week 2 - Classroom - CG Master Academy_5

so to begin with

we're going to grab a camera tracker node

and camera tracker right here

and the camera tracker node

essentially uses a source input

so it would be the plate that you want to solve

solve for so we will plug in our plate in this case

so here we have our um

landscape footage that we were looking at earlier

for the tracker

so um if I pop this out

so the tracker node

the camera tracker node

it it starts out by asking you essentially

what the sequence is

what the source is

so in this case

it's a sequence of frames

and here it ask you for the frame range

so you could go input

so if you're trying to solve a footage

that's a 200 frames

you could go off of that

or you could go off of your scene frame range

for us in this case

uh it's the same thing

but um if you had a different plate that had

another 200 frames that we weren't using

it would default to the input

wanting to solve the 200 frames

or you could go to global

which will match whatever your viewer is

in the timeline

so in this case

we'll just go global

um and then under the camera options here

it asks you what the camera motion is

so whether it's a free camera

whether it's a linear motion

um rotation only

um for the most part

um it does a pretty good job guessing what the

motion is in the shot

so you could essentially leave the

leave the set free camera

um but if you know it's linear

there isn't a whole lot going on to it

you could easily select linear in this case

but for this uh

example we'll just leave it at Free Camera

um here it's asking you whether you know the um

if you wanna

if there was lens distortion on it or not

and then focal length

which is a handy option

by default it's set to unknown constant

but if you happen to know

for example

if it was a footage that you shot yourself

or if it's a plate provided to you

and you happen to know what focal length was used

whether it was a 35 millimeter

50 millimeter etc

you could select

um you know

you could select known

and here you could type 35 millimeter lens

for example

or if you think it's an approximately

uh 35 millimeter lens

you could say approximate constant

and you could um

go with that

depending on what um

what information you have provided to you

if you don't know what the lens is

then what you could do is just say unknown constant

and nuke will try to

nuke will figure out what the lens focal length is

um as it does itself

um from there it's pretty straightforward

um what you would do is you would

first thing you would do

you would sit uh

select track in this analysis tab here

so right now if we hit track

you could see

nuke is adding the

adding in these auto tracks in the camera tracker

and it adds as many points

and you could

see some points as kind of disappear or reappear

and um it's essentially nukes

nuke is just trying to

add as many points as it

can to try to solve for this camera

so what once it hits the last frame

it goes backwards

just for accuracy sake and to help it solve

and once that's completed

you could kind of see if we scrub a little bit

a lot of these points are sticking fairly well

and if you hover over them

it tells you the length of that track

so so far it's done a pretty good job

so what we're gonna do at this point

if we think nuke has got it figured out

um we simply would hit solve

and you could see

now the icons have changed on this image

these green ones with an X represent good tracks

the red ones are rejected tracks so they're not good

and these orange ones are not used tracks

um so if we play through these we have a lot of good

good green ones that have locked on fairly well

um so to clean this up a little bit

what we could do is go to this Autotrack tab over here

and we could pretty much just say delete unsolve

and it's gonna ask us

it's pretty much gonna say

it's gonna delete these points

and you can say yes

and then we could also delete

the ones that were rejected

which would be the red ones

and we'll say

are you sure

we'll say yes

and now we're pretty much left with all the green

all the good tracks in this case

and if you press play

it's they're doing a pretty good job

these are all pretty good track points

now once we've got that and we're happy with it

we simply go to this export section

and by default it asks to export out a camera

so here we would just say um

it has the option of linking it output

so in this case we're just gonna say camera

and then we'll hit create

and now you could see

since we had this link output checked

this camera is linked to this camera tracker

do we could also

we could uncheck this and hit create

and now we have a free free standing camera

no longer attached and linked to this camera tracker

um but you could do um

a cam you could do a camera scene

and if we hit create here we have

we've created a camera scene which has um

outputted a point cloud

a scene node and a camera too

so let's delete that

I'll delete this camera one

and then what we'll do is we'll create a scene

and I'll do link output and we'll hit create

and now we have ourselves a match move camera

which you could rename if you wanted to

so we could hit n to rename this and we could say

match move camera

and then now we have our point cloud and our scene

so to see what this looks like

we could go into 3D space

and over here we could select our camera

and if I lock our camera

and we're looking at our point clouds here too

so if you press play

you could see it's done a pretty good job of

picking up on that pan that's in that plate

even some of that handheld quality in it

and these point cloud representations

are a good indication of things sticking

you know there's a couple odd points in here

but for the most part

this camera is not doing anything strange

which is great

and if we if we double click our camera

and we look at the projection

you could see nuke assumes that this is around

roughly of close to a 55 millimeter focal length

which is good

the other parameters to look at in this camera tracker

um while we're at this um

this in this case

it did a great job solving for this plate

but sometimes you might have an issue where um

the it it doesn't do

it can't solve for this camera

like it'll get track points

but it can't solve for the camera

and it might give you an error

saying there isn't enough um

there isn't enough uh

tracking points or it needs a reference frame

so those settings are located under

the settings tap here

so what you could do here in this case

um you could uncheck

you could check this

and you could set a reference frame

so you could say frame 1 was the best frame

so use this as a reference to

try to solve for this camera um

or the other thing you could do

it complains about keyframe spacing

so you could lower this keyframe spacing to

you know point two or point one to help it

try to analyze a little bit better

so generally

if you're having issues solving for a camera

um the reference frame and keyframe spacing

or the two parameters

I would recommend checking in

um the other thing you could do to help if

you're having issues solving for a camera

is there's a tab here called User Tracks

and what you could do is

help the camera tracker by

um adding in your own tracks in here

so not only can you add a track

similar to when we did our user tracks

or you could

let me delete this one

or you could um add

import a track um

from a tracker note that you already have in the script

so what you could do is you could say

import tracks oops sorry

not import tracks

import tracker

and nuke already knows that we have a tracker

one in the script

so if we said okay

you could see it added in

or three user tracks that we had solved for in our um

earlier video in

with this tracker one here

so nuke has added those track points in here

so you could use

you could use

2D track points

to help solve for a 3D camera in this case

so in this case

nuke had a good job of solving this on its own

so we could just delete this

but it's pretty handy to be able to

incorporate

2D track points that you've already solved for

using the tracker nodes and help

the camera tracker solve for it

but in our case

it did a good job

and if we look again

in our 3D space

um if we look in this default view

and scrub through our timeline

you could see this camera is behaving as we'd expect

it's panning a little bit to the left

it doesn't have any um

it doesn't do any weird x

y moves or weird moving Z

so that's an indication that we got a pretty good

camera solve here

in our upcoming videos

we can look into how to use this match with camera to

use the data from it to um create um

take take 3D point data from

what was generated in the point cloud

and use it with a note called Reconcile 3 d

and we'll be sure to dive into that in the coming video

hopefully that helps explain

the camera tracker a little bit um

the other options I would say

or things that you may need to play with sometimes is

um I forgot to mention earlier

is you have the option of using masks in here too

so if there's other things flying in this shot

for example

or things that might obscure your image

you could use um

a roto shape or mask specific to this plate

and set the mask

so the um the

Nukes 3D Tracker doesn't try to solve for areas that

you know are gonna be problematic

and it could just focus to a region that you've

selected in the

in the mask option for this