Newbie Roto Question

I have some footage of a pan shot inside a church. I want to replace the stain glassed windows with pictures. So I used mocha to roto the window shapes during the panning shot and exported the shapes to Fusion. In fusion I created a polyspline and pasted the mocha shape data into it and all went fine. So basically I loaded the original footage into fusion, added a merge tool and the polyspline and loaded a picture to use as a replacement for the windows. The problem is when the shot pans it also pans thru the picture that i wanted to be stationary. So basically it looks like I'm looking thru a shape window and panning around the photo, rather than looking at a stationary picture on the wall. What am I doing wrong?

Mr John,

We were all newbies at some point


I recommend exporting the shape and the tracking data.
Make sure perspective is turned on in the Mocha tracker, export as Fusion comp.
Make sure in mocha you set your output region for the track at each window corner.
Once in fusion, you feed the window replacement into the tracker.
It will then take the image, squeeze it into the shape and position of the windows using the
4 corner positions exported from mocha.
Then mask out what you don't need.

NOTE: Mocha outputs fusion comps starting at frame 0, if your comp started at frame one, you will have to shift the keyframes by 1 once you bring the mocha comp into fusion.

TIP: I usually just copy the tracking results to clipboard and paste in fusion

Well, you need to matchmove your image to original plate. Exporting shapes and tracking data from Mocha are different approaches. Shapes are masks, and tracking data is a tracker with 4 corner pins.

Thanks Roni - Your suggestion fixed my major problem with keeping the image stationary. However, using the corner position in the tracker resulted in my whole image being squeezed into the window.

Thanks Yuri - the match move worked perfect. I tried using the corner position, but it was squeezing and screwing up the aspect ratio.

I added the resize and crop tools so I can size and pan the image file I'm placing in the window.

The 4 corner squeezes the entire image, which means you should pre-crop it to match the aspect of the region your tracking points are.

This is vital when you need perspective as match move won't work for that. When you run into that workflow, ping us again

Rony,

In my case the church windows were arched, not square. So in order to use the corner position method, I had to adjust my corner positions much larger than the church window in mocha. Then use the mocha shape data to mask.