Rotoscope: Putting Shadows BEHIND an actor. (non-plate)

System: Mac OSX 10.5.8
Mocha AE. Aftereffects CS5.

I’m a newbie just starting in Mocha AE. I’ve followed Steve’s first tutorial, and applying it to a shot I’m working on for a short film.
The goal is to composite shadow footage BEHIND the actor’s arms.
Footage screengrab. DVCPRO HD 1280x720
23.98fps
Image: http://img835.imageshack.us/img835/954/platey.png (ImageShack - Best place for all of your image hosting and image sharing needs)
In Mocha AE, I tracked the movement of the actor over 6 seconds. Downloaded Mocha Pro (unlicensed) and opened it. I have 2 layers, the loose roto, and the clean one. both are linked. The tracking is about perfect for the 6 seconds.
Image: http://img714.imageshack.us/img714/3954/actormotiontracked.png (ImageShack - Best place for all of your image hosting and image sharing needs)
One of the 2 wings, to be placed behind the actors arm.
Image: http://img695.imageshack.us/img695/452/leftwing.png (ImageShack - Best place for all of your image hosting and image sharing needs)
I need to rotoscope him out, so I can put WINGS behind him on a layer, then PASTE him back over it. I understand you do a separate roto aswell for the background in this process.
Can I do this in Mocha AE? I have downloaded the trial of Mocha Pro…
The mocha tutorials are great, but I’m pretty lost here interms of the workflow. I’m not used to dealing with masks.
Do I import the raw clip into AE then export/import the tracking data of the actor from Mocha to Aftereffects? and cut/paste, layer in the wings behind him?..
Or can i do it with the removal tool in Mocha Pro (unlicensed version) comp it there and export?
I’m in the woods, and have about a week to get this shot done for a former ILM vfx coordinator…it’s my first real job. pro-bono, but I want to nail this down. learning as I go. Thanks in advance for any help/workflow suggestions/links.
Warner

Hi :slight_smile:
Let me address your questions:
“I need to rotoscope him out, so I can put WINGS behind him on a layer, then PASTE him back over it. I understand you do a separate roto as well for the background in this process. Can I do this in Mocha AE? I have downloaded the trial of Mocha Pro.”
Mocha is a software designed to help you make clean plates, rotoscope, track objects, and do screen inserts and corner pins. It is not intended as a main compositing package, but a compositing aid. That said, in mocha Pro, you will be able to use the insert tool for simple a over b comps and I’ll explain that at the end of the post. Otherwise, you will need to export his roto into After Effects or a similar package to composite the wings behind him.
“The mocha tutorials are great, but I’m pretty lost here interms of the workflow. I’m not used to dealing with masks.”
The workflow from mocha to AE and other packages is pretty easy. What you do is select the mask layer you need to composite from mocha, and make sure you are in the “track” tab, go to “export shape data” in the track tab, click on “copy,” head over to After Effects and just paste the shape data right onto the layer you need the shape on.
“Do I import the raw clip into AE then export/import the tracking data of the actor from Mocha to Aftereffects? If so, how does that work?”
The tracking data, like the shape data, can be exported right out of mocha and copied and pasted into After Effects. The tracking data is represented by the surface tool, which tells you where your corner pin will be. You can change its shape to fit whatever you need.
“Or can i do it with the removal tool in Mocha Pro (unlicensed version) comp it there and export?”
While the removal tool is awesome and saves you tons of time for complex replacements and stereo compositing, for this shot it might be a bit like driving a ferrari to work. You really just need to put the wings in a layer above the footage and hold the actor roto out of them in After Effects, and it looks like you’ve quickly rotoed out the actor in mocha already, so you’re halfway there.
Now, if you want to use the insert tool to put the wings in the shot and render them out as an element for your comp with motion blur, thats a great use of mocha Pro.
To do that (this will only work if your actor track is nice and solid):

  • On your actor roto layer, align the surface tool (blue square in the top of the viewport) to where you want the wings to be.
  • In the layers tab, so to “insert clip” and navigate to your wings,
  • the wings will now show up inside the surface box,
  • in the “insert” tab go to the “comp” section and click on “use background clip alpha” and then click “invert”,
  • switch to the “insert” section in the “insert” tab and click motion blur on.
  • Render this out of mocha by hitting the render forward button and export the frames to a format you like best.
  • You can be done here if you just need a simple A over B comp.
  • If you need more than opacity and motion blur for the wings, drop the renders into your comp and add any effects you need to onto your nice, new element already rendered out with motion blur and tracked to your actor.
    Hope that helps, but I do recommend working more on watching our videos online and working on more shots with mocha to understand the workflow better. We hope you like mocha Pro, and I’d like to let you know you can purchase the upgrade from mocha AE to mocha pro in our online sore for a reasonable price of $895, and that included our amazing roto tools and planar tracker, our remove tool, our stabilize tool, our insert tool, rendering out mattes and elements with motion blur, and a host of other great features. http://webshop.imagineersystems.com/index.php?dispatch=products.view&product_id=29894
    Cheers,
    Mary

Hi Mary,
Thank you so much for that concise post…I’ve been attempting both ways, from mocha AE to Aftereffects, and tonight in Mocha Pro. I’m seeing some issues with both ways, but getting closer, thanks to your post. I’m going to play around some more, watch more tutorials. I’ll post updates on my progress or unprogress tomorrow. Thanks so much again for your help.
Warner

Hi Mary,
Thanks again for the directions, I had some problems but will try again, as i must doing something wrong.
I have a separate question related to Mocha Pro. If I wanted to put a green background behind my rotoed actor, is that possible? I tried experimenting under the parameters to no avail.
Cheers,
Warner