How do I shift a clip to start later in time?

[Anonymous]

I have a greenscreen shot that I want to have start at a specific frame in relation to the Backplate shot its comped over, without losing the length of the greenscreen shot.

Here’s what I mean:

Greenscreen Layer: ___________ _________
Backplate Layer: _____________________
Composite Total: _____________________

You probably figured out what I meant without the graphic, but I wanted to be sure I conveyed what I wanted.

I’m sure there’s a way to do this in Nuke, I just don’t know what it would be called.

Thanks in advance.

[hasegawa]

You have more than one option. You can use the TimeOffset node or the Retime Node, which is what I prefer.
Both are under the Time Tab.

Cheers
Franz

[Isteve Lee]

Hi Franz,

In the Retime node, what changes do I make to have the clip start 10 frames later? In this case, both the GS clip and BG clip are the same length.

What if the greenscreen clip is shorter? How do I ‘slide’ the shorter clip to the right or left in time?

The settings in the Retime node aren’t clear to me.

Thanks.

[Robin Lind]

If you just want to shift your read node in time, you can also use the “frame” field of the Read node. Just put n expression in it.

Like frame-10 for your sequence to start 10 frames later than it should

or frame/2 if you want to divide its speed by 2

you could also do wacky things such as this one : frame + (18*sin(frame*5))

[hasegawa]

In the Retime simply switch on “output range” and tell Nuke the Startframe. I prefer it this way, because it makes the script clearer if you have to hand it over.

[Isteve Lee]

Nothing is working. I think I have to clarify what I need. I have two scenarios that I often come across:

Scenario #1:
I have a clip that is shorter then the comp itself. I want to have this shorter clip start and end at specific frames, maintaining the full length of the clip itself. In Combustion, I would just slide a “bar” in the timeline to do this. How do I do this in Nuke?

Scenario #2:
I have a clip that is the same length as the comp. But, I want the beginning of the clip to start at another frame and “trim” the end of the clip to match the last frame of the comp, if needed. How do I do this in Nuke?

If someone can share some screen captures of the settings, that might make it easier for me to understand.

Thanks! 🙂

[Dejan]

Basically the “input range” there is where you trim your source, “output range” is where you “slide” it.

Just take a look at the node’s help by pausing your cursor over each field, and take a look at the chapter 9 of the Nuke pdf doc.

[Isteve Lee]

Hi dg,

I’ve played with the settings and I can’t get it to work. The sequence I’m working with is 40 frames long. I want to trim the FG layer to 20 frames, and have it start at frame 20. But, the FG layer just freezes before frame 20 and starts moving at frame 20. I want to see just the BG layer before frame 20, when the FG kicks in.

I’ve tried different settings for the before and after menus but nothing gives me what I want to see. There’s obviously a workflow to this tool, but I don’t think its readily apparent; at least not to me.

I’m confused. :-/

[Pete Hoffman]

I have some examples for you, but I can’t find a way to attach my zip file (under 1mb in size). I can mail them to you if you want.. will need an address.

Cheers,

doodle

[Isteve Lee]

Thanks, doodle.

Can you grab a screen capture of your Retime settings and add it to your next reply? I can probably get a better idea of what to do with that.

[Pete Hoffman]

It won’t even let me upload an image :confused: too tired for this

[Dejan]

@vfxtodd 27542 wrote:

Hi dg,

I’ve played with the settings and I can’t get it to work. The sequence I’m working with is 40 frames long. I want to trim the FG layer to 20 frames, and have it start at frame 20. But, the FG layer just freezes before frame 20 and starts moving at frame 20. I want to see just the BG layer before frame 20, when the FG kicks in.

I’ve tried different settings for the before and after menus but nothing gives me what I want to see. There’s obviously a workflow to this tool, but I don’t think its readily apparent; at least not to me.

I’m confused. :-/

input range 20 – 40
output range 1 – 21

[Isteve Lee]

Hi dg,

I still get frozen frames where I just want to see the BG. I’ve played with the “before” and “after” settings again as well, and still can’t get it to work.

I know Nuke isn’t an editing program, but I’ve been able to offset clips in time in Combustion without a hassle. The process seems convoluted in Nuke.

[Dejan]

Read the docs and take the time to pause the mouse cursor for a moment over each field in a node, all the info you need it’s there. You are getting freeze frames because your before and after dropdowns must be set to “hold”, change them to “black” and you should be fine.

[Isteve Lee]

Hi dg,

After much playing around I came across a solution.

I added a TimeOffset node and set it to “10”; which basically “pushes” the beginning of the clip 10 frames later. To that I added a Switch node and keyframed it at “0” at frame 1 and frame 9; which basically turns it off for nine frames. Thus, hiding the “freeze frame”. Keyframed it at “1” on frame 10 where I wanted it to kick in.

With the Switch node I am able to hide the top layer while revealing the BG, as I wanted. I knew there had to be a way. It’s fun learning Nuke. I’m liking it more and more every day.

Thanks again for all of your help.

[Author]

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