Techniques for marker removal in NUKE

[dew]

Hey guys!

I searched the web and the forum for general consultation in this matter but there isn't much that goes into detail.
So sorry if this has been posted before and I hope everything else is correct since this is one of my first posts



I am new to NUKE and maybe this is more of a general technique kind of question but ill shot and see where we get.
I have 5 mins of footage recorded in 120 fps. Quite a few frames and all of it is going to be tracked and the markers removed.

I have started out in nuke with a few tutorials and gotten quite far but have experienced some issues and gotten some questions.


1. Is it possible to use a 3d camera track from PFTrack (or nuke) to remove markers using that?

The following questions are about using 2d tracking and cloning/shapes.

2. How do I change the actual feathering of a clone brush?
I have a few markers on a wall with a long gradient shadow on it. Would be awsome to feather the cloning.

3. Is it better to clone in Photoshop and then replace with that? guess id have to introduce new grain to those stills then?

4. When removing markers on a mixed motion shot that dolly's and pans the room the markers get bigger and smaller. What is the best approach here?
Is it better to clone different parts of the shoot or perhaps track two corners of each marker to introduce scaling in the track?

I have more thoughts and questions but well start there.

Cheers

dew

[g00lan]

If you already have a 3d camera track and the geometry for the scene, then you could clean one frame, project it on the geo and it will stick to that spot. You could also put Axis nodes in 3d-space and get 2d data from them.

To change the feathering of a clone, change the Hardness value. It's under the Stroke tab I believe.

If you just need to clone, do it in Nuke instead of Photoshop, but this is just my opinion, don't know what's best.

Regarding Question 4, No Idea^^

[ddtddt]

Q4 ..is this a blue/green screen shot....sometimes u can key them off by using the green channel as a key channel..or paint them or track them out..u would only be painting where they go behind objects obviously...

gl

[dew]

Thank you for your replies!

No it is not a green or blue screen. Actual footage. But since there are so many frames for each shot and the camera is very smooth I was hoping to be able to just paint once and use some sort of tracking.
But because of the scaling I have to do one paint node for the first 100 frames and stop that there, then for the next 100 and so on.

So how do you guys deal with markers that get bigger and bigger in a shoot?

dew

[ddtddt]

can u post one frame pls....?

[dew]

Hey!

Sure.
Here is one frame. After this we move closer and closer and get very close to the table and then move left (steadicam).
(The red parts are just masks for pftrack)





dew

[beaker]

I would take paint a clean frame. Then do a 3d track, add cards at the locations of all the tracking markers. Roto and project3d a bunch of little patches over the tracking markers using a still frame camera of the frame you cleanplated. Then scanline render, motion blur, grain, merge back over the plate.. This will keep everything in perspective and the right size as the camera movies. The only thing your going to need to play with is the shadow of the woman as she moves around the room. I would just do that as 2d roto to darken the shadow over the patches to match the plate.

[dew]

Alright! Got a 3d track done.
Exported the camera from pftrack and opened the script.
Done pftrack before but since I am new to nuke Im not sure what to do here...

I can see in the 3d view that the track ses great and the export is fine from pftrack.
But when I attach the camera01render to a viewer the yellow tracker features dont follow the footage.
How do I attach the yellow feature objects from pf to the footage?


dew

[ddtddt]

What beaker said ^^^^^^

I dont use pf track...try this page http://www.vfxtalk.com/threads/33058...+track+to+nuke

Try nukes camera tracker. its really is good.

As a matter of interest, why did they place tracking markers in that shot? Seems plenty to track on there without markers....

[dot]

i found some other way, add a mask around the marker and add a node Marker Removal its is working grate , try this may be helpfull

[beaker]

I can see in the 3d view that the track ses great and the export is fine from pftrack.
But when I attach the camera01render to a viewer the yellow tracker features dont follow the footage.
How do I attach the yellow feature objects from pf to the footage?

you can add cards to the scene and snap them to the yellow features. Then project3d a clean frame onto those cards. I would check out some of the basic nuke 3d tuts here for an intro on using it.

http://www.thefoundry.co.uk/articles...ection-basics/
http://www.thefoundry.co.uk/articles...uke-rotopaint/

[dew]

Wow thanx guys!
Like 3 different answers here. Think I will test everything and see what flyes.
Been having heavy pressure at work so haven't had time to try anything yet.
However, hopefully this weekend ill have some spare time to dig deeper and
perhaps produce a clean plate


Thanx again!

Ill post back with more questions or answers if anyone is interested.
And about the plate. It was filmed 1,5 five years ago and I had NEVER even
seen a tracking software so it was me and my buddies mistake to put all
those tracking markers there...
But at least we will learn to do some painting

dew

[ddtddt]

LOL will be simple fix anyways have fun..post the finished shot when you done...and nuke script...perhaps we can refine it after????

[dew]

Hey guys!

Im working on the shoot right now.
Going to have to ask my partners about how much detail I can give you about the shoot so stay tuned for that but I got a few more questions.

I watched those tutorials recommended by beaker and the ones by fxphd found on the foundrys website.
Got a good understanding of both a 2d approach and a 3d approach now.
Managed to do both and get quite good results or at least the scripts working well.

However as I stated I've got a few questions.

1.
3D proved to be a very time effective way of doing marker removal (at least when the shoot has to be motion tracked any way).
However my results weren't that good and id love to post some examples but for now ill have to explain (not allowed to show to much of the shoots before we release).
The thing is that when I paint a clean plate in Photoshop and then project that onto cards it does not stick perfectly.
Well it is perfectly tracked and everything put because of the perspective change when the camera moves all those lines and lists on the walls get slightly skewed.
So it actually sticks great but if I project an image of the shoot from the middle it wont look that good in the start and end frames. Simply because of perspective.

2.
Also since the camera and focus changes its not possible to use one still unless I bring in a blur and key it like the camera blur.
But that's not a real problem just me evaluating this method vs 2d replacements....

3.
Another problem with cards is that the edges are hard and I cant blur the edges since nothing else is blurred.
So how would I fade the edges of the cards when using the projection technique?

And more of a 2d question for dot:

4.
How do you set up the Marker Removal node with a bezier and tracker?
I've gotten it to work with masking by a rotopaint node but it doesn't look as good as yours.
Do you use a bezier?
DO you add blur to the mask?



Sorry if its hard to understand with out images but ill see if they'll let me post some.


dew

[g00lan]

1. 3D proved to be a very time effective way of doing marker removal (at least when the shoot has to be motion tracked any way)...

You could make a clean still from another perspective and use that one when the middle get's to distorted. I do have a hard time understanding exactly what you mean, but I think it would work doing
say 3 clean stills, and changing between them or something.

2.Also since the camera and focus changes its not possible to use one still unless I bring in a blur and key it like the camera blur.

You could (z)blur/defocus it after the scanline render node. Or I haven't understood what you mean.

3.Another problem with cards is that the edges are hard and I cant blur the edges since nothing else is blurred.

Are you using AA? It's enabled in the scanline render node.
It's possible to blur the edges by using the Edgeblur.

4.How do you set up the Marker Removal node with a bezier and tracker?

Don't know to who you refer this, but you can track the markes and put the data in the beziernode. Add a Layer and put your roto inside that layer, go to the transform tab and there you can link the trackerdata to it.