Dolly Shot, Rig Removal

Hi, was wondering if someone can help. I have been working on this shot for a few days and haven’t had any luck. I have attached two screenshots to show the footage describing the start and end of the shot and movement of the camera.

Here is our current status:

  • We have managed to stabilise the shot.
  • However we cannot remove the rig (We have tried seperating out the tracks into sections base on the planes it sits across.
  • No matter how we track the floor area, when we use a Retouched Clean plate, the image ‘rides up’ and is not correctly mapped to the floor.

Could someone please advise how best to solve this? We have spent over a week trying to figure this out.


Graceful Monkey Team

Mocha doesn’t like ground plane tracking if it gets extreme. Start the ground plane track at it closest point and track backwards. Try to limit resizing the track area too much. Seems like you should have enough features to track. Make sure you use the Adjust track module to realign the surface with the ground features.

If it was me, I’d use the camera right side and flip it over to the left to cover the rig. Shouldn’t even need a track for that.
Maybe just roto some of the paper back in so it’s not symmetrical.

The robot looking thing will need several tracks if there’s much parallax.


A week, wow. send me a link to the shot and I’d give it a go.
Seems like an hour’s worth of work.


Sometimes new users find their shapes don’t behave as expected. If you using perspective when you track, it may be that your surface is going behind the camera in mocha and corrupting the data. In mocha, problem splines can occur when the tracking data has become so skewed it goes off or “behind” camera, the keyframes the tracking data generates can throw the shape information out of order. You may need to re-track the shape using only translation, scale, rotation, and shear instead of perspective. I actually recommend users do not use perspective when they roto organic objects like people and animals at all, but it’s great for buildings.

This is why when shots zoom forward like this you should track backwards, the surface tool will go into the camera space and not behind it. Specifically for this remove you probably DO need to track perspective. Which means you will have to carefully watch the track via the surface tool. For ground planes, I also like to make sure I track with the track linked to “none,” we call this unlinking the track. It will read all the pixels moving beneath the shape like a scanner. Finally, if you still aren’t getting expected results, your track might be off (or your stitch might be), use adjust track to make corrections on the track before you do your remove. That should help a lot.

Please let us know if you have any more questions and we will be happy to help you.

Thanks for the advice guys, we have gave it another try today and still having trouble with making a rock solid track to the floor to do the removal.

Here is a link to the footage, if anyone can help us out that would be great.


Graceful Monkey Team

Don’t track the floor, track the rig.
Remember this is about planes… And everything Mary said! always listen to

1 Like

sorry no MXF support on my computers
Odd your .mxf file has a creation date of Jan 2016, too


If you need to work with MXF files occassionally, you might want to go get yourself the free version of BlackMagic Designs Resolve. You can transcode MXF files to a number of formats with in it.

I played with this file a bit. You need to just get a really good ground track. Keep moving your shape to get more data and track from near the end of the shot. Move your surface tool back into frame to keep it from twisting in on itself. This is just a hard, tedious shot. But it can be done. At the very least, you can simply hook rotopaint up to the track for a cleanup the problem areas solution as well.

Thank you so much Mary. Would it be possible for your to share your file so we can use this as a starting point?

Yes this footage was shot in Jan 2017 actually. It’s for a short film that’s been put on the back burner as we’ve been so busy. Hence we have little budget to play with for the clean up.

I sure can, but at the end of the day. I am off to a VR event and won’t be
back until later.

Stand by!


Mary Poplin
Boris FX Product Specialist
1-888-77-BORIS Main Office
(424) 645-5005 LA Office

Thank you so much Mary, no rush, enjoy your event.
We really appreciate your help on this.

It looks like I didn’t save it, I looked for it when I got back from the show and didn’t find it, however, I will tell you how I got better results.

I tracked from the end of the shot to the beginning, and I made holdout masks for the robot, the rig, and then tracked the ground.

When that was done I used adjust track to adjust slippage.

Here’s the thing to watch out for though, make sure your surface tool and your shape doesn’t get behind the camera. Keep your surface tool well inside the floor space and don’t let the splines come too far forward either.

Alternately, just do an offset paint for most of the rig and then a simple patch for the back of the robot body and you can solve this shot that way. It’s a pan, offset paint should be pretty simple.