All language subtitles for 2月29日 (10)

rotoscoping in Nuke 5 tips for beginners

so tip No. 1 is to identify motion paths

so what do I mean by this

we have a footage here of a of a person

sort of picking up some

objects and and kind of moving them to a

different spot

so far task was to rotoscope this hand

and we wanted to isolate it and create a mat

you know

one of the mistakes that beginners might make is

kind of arbitrarily placing keyframes on your timeline

so we have a timeline down here in the corner

and sometimes people

think you just put a keyframe you know

every 20 frames or every 30 frames or

maybe shorter if it's a shorter shot

but we have a lot of frames here

but the problem with this is

you end up kind of counter animating your shapes

so if you were to look at the motion of this hand

and what you want to do always

before you start your footage is to

watch the whole footage

and try to identify some patterns in motion

there are usually some characteristics of motion that

are mostly always the same

unless you have really chaotic motion but there are

some

principles of motion that we're going to talk about

briefly

that is pretty much the same for most objects so

if we just look at this and kind of play our footage

we can see that the hand is kind of going between

actually three different locations

so if we were to just put a keyframe at the beginning

and one at the very end

we're actually gonna miss

one of the spots here

so if I were to kind of draw it out on a

just sort of a motion path here

we can see we have like a starting location

which is here

we have like a top location

and then we have sort of an end location like this

and so if we were to just draw that out

it's basically kind of a triangle

so rather than

just arbitrarily

doing one at the start and one at the end

what you want to do is I is

place a keyframe at the

change of motion so where

an object slows down and starts to change direction

you want to look for those changes of direction

and that's where you

start your keyframes

so basically you would just put a

keyframe here at the beginning of your shot

when the hand reaches the top that's another keyframe

and then we would put one at the end

and that would avoid us

making the mistakes of having to counter animate stuff

because if we put a

keyframe at the beginning and one at the end

the rotor shape will just

slide between those two shapes like this

and then we're going to have to

kind of counter animate it to make sure it goes

up and all those kind of things

so you really want to watch the motion

put your keyframes that the key points of motion

changes and angle changes

and that will save you actually a lot of time

than rather than just arbitrarily

putting on random frames

one other thing to note is that usually objects

they kind of ease in and ease out

so that's something to keep in mind

so once you have your main motion points in place

so if you put a key from here here and here

usually objects will kind of

and this is a very chaotic motion

they'll kind of

ease in and ease out

so basically it will kind of slow down here

and it will start to speed up here

so those will be

another place

you'd kind of put your secondary keyframes

is just before

the object kind of

settles into its next position

so if you look at the motion objects

you know objects will gain speed

but they kind of have to gradually

get that velocity and

the same with decreasing

so that's something to keep in mind when

you're placing your keyframes

look for the directions of motion

make sure your ease in and ease out

points are there as well

and that's going to save you a bit of time

tip No. 2 is separate by objects so

what this means is

basically you don't want to roto objects together

especially if they're on different

planes of parallax

or if they're deforming differently from each other

so you can save yourself a lot of time by simply

separating the objects by different shapes

so if I go to the keyframe here

we can see I've taken the foreground object

and an object that's behind it

and even the area that you don't see

the rest of the object you can overlap those

two pieces and

it's just going to make it a little bit easier

because you can simply

just grab the entire shape as the shot is moving

rather than if you were to roto it like this

where the points are together

maybe do a little bit of better job

but

if the points are together like this

these points might slide along the surface

so one of the things you want to do

when your rotoing is not only consider

separate objects but also

and this seems to

sort of get looked over when your beginner potentially

is like you think that the points don't matter

kind of on where the edge it is

and that's actually something that's really important

because if you let your point slide around on your edge

you think

you're just trying to capture the silhouette of the

shape but it's not the case

you can get a little bit of a wobbly

edge if you put too many keyframes

or

your points are sliding around on the surface like this

like if the shape is

kind of going along and this point

doesn't stay in the same spot

so what I do is I typically look for a feature

you know

if we see that the black line is here on the hat

and I see that there's a point here

I would try to keep that point

as close as I can as this

you know sequence goes on

so that's something to keep in mind

so keep objects separated

keep the points

relative to the place that they're originally placed

and you're going to get a more solid roto by doing that

so tip No. 3 we have stabilize your footage

and basically

this is pretty straightforward but

it's something to think about if you have shaky footage

something like this

if we take a look

we can see this is sort of handheld

let me just kind of zoom in here

sort of handheld footage and pretty shaky

and all over the place in terms of the motion

and so if we wanted to rotoscope a few of these

fruits or

kind of things being carried in this basket here

again we want to rotate the object separately

maybe we want to isolate one or two of these

we wouldn't want to do every single shape as one shape

like the whole silhouette of this thing

maybe we want to color correct those to be different

color so

what we could do is take a tracker node

and we want to stabilize it

do a roto and basically match

move it after so we would add a track

we take a track and we try to find a feature

this is gonna be a little bit trickier because

the lighting is changing quite a bit

if we look at the footage

the lighting is changing quite a lot on there

so you might have to do a little bit of manual

2d key framing here but I'm not going to go and do a

complete

perfect track of this but just to show the example

so I could set the reference frame where we are

in the transform node

and we can try to find a good feature

also one thing we can

sort of turn on and settings here is adjust for

luminance changes

so that will help a little bit

with the changing of lighting

I do expect that it would probably go a little bit

crazy but we'll see

so I'm going to use the

C and X key on my keyboard

and I'll try to find a feature

maybe I'll go on the front here because this one's

a little bit more in the sunlight

if I hit C it'll track forward

so we can see it's popping off there

so maybe it's not the best feature

we'll see if we can find a different one

maybe this one here on the corner

we could try that

we could expand our range a little bit and hit C

so that one's working a little bit better

so I can use that one and sticking relatively well

and then we could just adjust it as it goes off

so C will track forward if I hit X

it will track backwards in time

so I can go frame by frame

and just make sure I get a couple good frames of this

for the example

and it if it's not completely

perfect you can you can always go in there adjust it

of course this window really helps so

pay attention to your sort of stabilized window here

and just see if it's kind of jittering so

if it updates properly which sometimes it kind of lags

but

this is a good way to see if it's jumping

so these two frames are good but between here and here

if it updates we can see it just

hops to the right a little bit

so we can just

slightly adjust it over

and then just keep doing that

until you get a really good result so

I like to make these window

really big if you're trying to get a tight

sort of track so I can kind of put it here and

step back and forth and just check

and try to get that

sort of sub pixel accuracy if you can

so that's how you can get really

tight tracks as well

so I was gonna actually make a different tutorial

just on that because it's very useful

to know if you watch that sort of sub pixel motion

this window really helps

so

just keeps stepping through

and we can see it jumps off here again

so we just slightly

shifts it over

and I think that's good enough for the example

if it's a little bit off we can always fix it later but

that's good enough what I'll do is I'll go here

I'll export a match move bait

I just like to do it baked

just because it doesn't mess up if this thing gets

kind of messed up here in accident

so we have our match move

and I'm gonna also do a stabilized baked

so we have the two of them

let's get the stabilized baked

once it's stabilized once it's match move

so we'll put the stabilize on there

we'll put our roto in between and then we'll put

the match move

sort of at the end and so

remember our reference frame so our reference frame was

151 I believe

that's our reference frame

so I'm gonna start my roto there

I'm gonna close all this stuff

and we'll just roto maybe one of these

we'll just kind of put a

quick roto here so we can drag it out

and I'll just drag it behind for now

and I'll just kind of go like this

so something like this

I can select all the points hit Z

and smooth it out

I use that quite a lot

I like to work with the Beze Curve

some people prefer to work with

the B splines

I just find it easier to have the control

so I like to just select them in the hit Z

to kind of smooth the corners

and we have something like this and we can view it

and this should stick a little bit closer

so you see

if we were to just roto on the normal footage

the difference is quite large

if I just step between the two frames

but if I'm looking at the stabilized version

if I step between those two frames

you see it's already done most of the work for us

and if we were to roto

without to stabilize a bunch of these different ones

we might be a little bit off in our track

like one might go up a little bit

another one might go a little bit differently

and then you're gonna get all kinds of jittering

so this is why

stabilizing

is really great because it's kind of getting the

general motion for

this large area

and so if your camera is moving if it's panning

you can stabilize that

if it's an object that's moving independently

like this one

you can stabilize that as well so

just things to think about

think about the motion

and think about how you can get rid of it

do your work and then reapply that motion back

so once we've got a roto

I'll just do another frame here

we can always just adjust the lines as we need to

just make sure it's like really tight

and I'll just do like three frames here

yes I think it's actually I think

actually there

so we're just not seeing it because it's in the shadow

so I like to step between my frames here

and see doesn't feel like any point is kind of moving

and if it is

we want to make sure that's not doing that

so we can try to

remove that sort of jump

make those jumps very very small

so something like this

I think it's a little bit off still it's

hard to tell with the light here

that's changing so much

but really it's easier to just kind of look at the the

point

so something like that is probably good enough

for now and

that's good enough and now we have an alpha

so we have our alpha here

if we want to use this back on our main footage

we reapply the motion with the transform match move

and now if I watch those three frames

it's going to move with the footage

so we're kind of reapplying that shakiness

and we have all of that there

and actually what we can even do

is now that we've done this here

this transform stabilize we don't want to run

the whole footage through stabilized

because you're going to get a little bit of filtering

it's going to blur your picture a little bit

so you actually

don't want to stabilize and do your work here

this is more just like a preview

so once we're done with it

we can kind of just unplug it

and we actually have the roto here with the match move

so you don't even

stabilize doesn't do anything at this point

we can just kind of disable it or keep it there

it doesn't really matter

and then what we can do

is just use this as like a color grade

so we can plug it in like this mask

and then we could use that

in whatever way we're trying to achieve here

so we can you know change the color of this thing

we could blur out our alpha a little bit

and just the basic stuff

so we have that kind of sticking

so that's something to think about

stabilize your shots when you can

if there's a lot of motion it's going to help

and especially if there's a lot of objects

you know you can also do planar tracks

you know if you have an arm that's sort of swinging or

a character that's moving a certain way

there's different you can use other types of tracks

it's not just the 1d track that we've done here

so the next thing we want to think about

are primary and secondary forms

so when you rotoscoping

typically there are

complex shapes that we can break down into

smaller and simpler forms

and so this is just a video we have this

kind of rooster walking here and

this is an example of this so

we did talk about separating things by objects you know

easily identifiable objects you can

you know like these leaves is very obvious which are

separate but

with complex forms

that have overlapping shapes

you can also do the same thing

you can actually break them down into simpler shapes

so an example of this might be

taking the body of this thing

and we can sort of like we could do a roto

of just you know maybe the general outline of the body

and sometimes some of the smaller feathers

might pop up independently so

rather than doing that on the overall silhouette

like adding to this main

body shape like this

we wouldn't want to just keep

adding little shapes every time something pops up

rather what you can do is simply create

smaller forms and whenever those

small shapes break the main silhouette

that is a good way to do it because

you'll kind of save yourself

a little bit of work there

so if I switches to different color

we can see that so you see a primary form

the little bumps that

create secondary forms

and this is a pretty useful technique

and you can as many of them as you need to

depends on the complexity

of the form that you're doing

for example this might be

another example if you're doing this sort of

tail thing here

you could do maybe like the main one

and then you could

break the smaller ones off because they're going to be

moving pretty differently

so you could break it up into

as many forms as you need depending on the motion

and of course you want to look at the motion

beforehand as well

so this is the same idea as we have the main body

we can break that into two different shapes

we could have the wing

I'll just do a real quick

sloppy one just for the example

and we could just like make a different color

to see it a little bit better

so that would be another secondary form so you see

it's not like one object is just one shape

it's like we're breaking it into many different things

and that's going to make it

easier to animate because we can just

you know we can rotate it

and things like that

the last one we have here is using rotational points

and now that we know about primary and secondary forms

this is sort of a similar concept but

really just breaking those

primary and secondary forms into

their independent motion paths

so most forms unless you have like really

a deformable object

isn't going to change size that much

so really

if you can just separate your objects into sort of

based on their pivots

the general size of those independent

shapes that you draw won't change

that much so really you can kind of rotate them and

just move them around

rather than moving a bunch of points

so if we're looking at this sort of

sort of dog kind of jumping here

there's a lot of motion going on but the

so general you know

volume isn't deforming that much

like the muscles and skin are stretching

but obviously the bone structure is going to stay

the same so

what you want to do is separate this into you know

many different shapes and just basically do it

how it's kind of structured in the animal

so you would kind of do

this area first

we could separate this into one shape

we could separate it here

like this

and we could do another shape maybe for the ankle area

like this

and

this is just a very very quick and

quick and sloppy one but

it'll get the idea across

and then we can do another one on the bottom if we want

so we could separate that into three shapes

maybe you could do two shapes

if you want to do it that way but

so as this kind of goes

what's nice about this is if

for example this bottom part rotates here

we can just rotate that form and just put it here

and then kind of go like this

same with this guy

we can just take this and move it over

and I'm trying to line up my points

remember what I said earlier

trying to keep the points in the same area

so I'll try to find a point

like the very corner of his sort of

I guess this would be like the angle here

finding that corner point and then

trying to get that lined up

and then trying to get the rest of the points following

moving them over and then hit z to smooth

that's good enough

so you can see how it's a little bit helpful to

just kind of separating the different shapes here

we can have them overlap and it doesn't matter

and it helps us kind of keep our points

more clean as well

rather than having

one shape with like tons and tons of points

that's basically it

yeah just keep that in mind if objects are rotating

it's a really good

opportunity to use different shapes because

we do have this pivot point

if you hold control

you can put the pivot point on

the rotation and we can just rotate

and it will pivot around that point

so

a lot of real objects will rotate around

a different sensor point

and you can utilize that to save a little bit of time

and that's basically it so that's 5 tips for beginners

to increase your speed with Roto