View Full Version : Getting rid of Markers

04 April 2005, 07:21 PM
Hello, I was wondering how do most of you get rid of markers? I currently have a shot, a dolly right to left. It is a wide shot with markers in the fore ground and mid-ground and some representing the wall of a CG house. I have the scene matchmoved and now I want to get rid of the markers. This was shot on an actual location. No green Screen. There is no motion control camera, but they did do a take of the scene without markers.

What I did was export the camera data out of Maya and brought it into After Effects. I then used just a still of the ground and apply that to the Maya camera. It doesn't work that well as it really looks fake. Is there a better way to do this?

Any help would be appreciated!

04 April 2005, 09:51 PM
Yay... The joy of prep!

Various techniques:

1) Roto around the marker, then track the roto to the marker. Move the plate slightly and reveal the moved plate onto the original plate through the tracked roto. This works well if it's a relatively plain surface (and there is no rotation)

2) Paint, frame by frame! This is usually best when there's something like hair in front of the marker, or a moving edge. If it's a solid area, then the paint can often look quite jittery

3) Paint a single frame, and track part of it onto where the marker is.

I'm sure there are more - these are the techniques I use most often.

04 April 2005, 03:23 PM
Thanks for the reply! I will try the first one, unfortunately the ground is not very plain, it's snow with lots of footprints in it and the shot has a bit of rotation in it as it's a dolly right to left.

I tried painting out but I couldn't get the frames to match all the way through.

Would it be possible to import the camera data from my 3d application and then assign that data to the position of the masks? I used Bou Jou to matchmove the shot and imported that data into Maya. I'm not sure I can import from Bou Jou to After Effects.


04 April 2005, 03:29 PM
A dolly shouldn't be a problem. By rotation, I meant around the view axis..

As long as the point, say, 30 pixels to the right of the marker is tracking the same point on the ground all the way through, you should be okay with this one...

04 April 2005, 11:59 PM
I'm not sure whether Hugh actually meant this (my english ;-) but what I do quite often is to to put a copy of the sequence on top. for this top plate I draw an inluding mask a little bigger than the marker, right beside/above/below the marker, track the axis of the mask (marker as source) and then move the plate a little so that it lies on top of the marker. This way you always get what's near the marker in that actual frame...


05 May 2005, 10:04 AM
You can propably also use the clean pass they shot.

Since it's not motion control, you can "just" use it, you'll have to adjust its position manually on a number of key frames. And you may have to do that for every marker.

My point being, for every frame in the real shot where you need to remove a marker, there's propably a part of a frame in the clean pass that fits. So use that.

Good luck,
- Jonas

05 May 2005, 10:17 PM
Thanks everyone for your help! I'll let you know how this turns out.

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