Keeping the Blood patch still, during camera movement

[skliew64]

Gday, 

I have a scene, where our protagonist has been stabbed. Another actor comes to his side to try and rescue him.  In the shot we have the camera moves up like a crane. (Shot with a Mavic Drone). The Director wants me to digitally add blood onto the protagonist t-shirt. I have tried motion tracking the sequence, then tried to add a null so that I could later link the digital blood onto his T-shirt. However, I notice that the blood patch, doesnt stay quite still. Possibly due to the movement from the camera. Is there a way to fix this or 

Whats the best method to do this. ?? Greatly appreciated.  

regards

Steve

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[Mike_Abbott]

You will probably need to do a 3D camera track of the scene. If you're not familiar with that, here's a introductory tutorial:

https://helpx.adobe.com/uk/after-effects/how-to/add-3d-text-video-footage.html 

[Rick Gerard]

My first thought would be Mocha AE and corner pin tracking. We really need to see the shot to recommend the most efficient workflow. It all depends on how the camera and the actor move. Here are a few workflow options that come to mind:

• Motion Stabilize the footage so the t-shirt so that it doesn't move, then put the motion back in the shot and add it to the blood graphic
• Use Mocha to corner pin track the t-shirt then use a combination of CC Power Pin and Corner Pin to add the blood graphic
• Do a Camera Track of the shot and attach a solid to the surface of the shirt (if it doesn't move in the frame) and use the solid as a guide to position the blood graphic
• Use a third-party effect like Lockdown to motion track the shirt and add the blood graphic
• Use Mask tracking + the Create Nulls from Path and a bunch of fiddling to attach the blood graphic to the shirt

I could go on and on. Without seeing the shot it's going to be awfully difficult to point you to a really efficient workflow.

[skliew64]

Thank you Rick, For your suggestions. Please find enclosed, The Shot I was referring to. 

The clip goes for 20 seconds. Any suggestions would be helpful and greatly appreciated. 🙂 

The Director wants the blood to be added digitally, on the (A) protagonist (wearing WHITE - T shirt). Please see attachment image 2 - Shows a red dot, representing the stab wounds to be inserted. 

Steve

Blood is to be located between the A and B actor. 

Clip courtesy from Playtime Motion Pictures

[Mathias Moehl]

Looks like it is perfectly doable with the mocha stabilized precomp approach I outline below. No need for a 3d camera track here. Just make sure the track is not distracted by the shadows. If the track is not accurate, you can also refine it after the fact as described here

(this works with both corner pins and stabilized precomps in the same way)

[skliew64]

Cool.  Thanks for the reply. Would I need to have the full version of Mocha?? As I can see the version Mocha your using in the video, has more features. The one i have is a basic one that comes with already built in After Effects. 

[Mathias Moehl]

MochaImport+ works with all versions of mocha, also the ones that are bundled with any version of Ae. The only thing you need in addition is my extension MochaImport+.

[Rick Gerard]

That is a perfect example of a shot that should be tracked in Mocha AE, then you duplicate the footage layer, apply Corner Pin tracking to the duplicate comp, then add CC Power Pin and tie the corners to Corner Pin, turn off corner pin and then pre-compose and apply corner pin again to the pre-comp. Mathias' Mocha Import script makes this a little easier but there's nothing really to it. Here is an old tutorial I did that shows the workflow to stabilize a TV. Once you get the stabilized pre-comp it is very easy to do the required roto and get the bloodstains to look very realistic. 

Here's my old tutorial:

If I have your permission I'll take your shot and show you exactly how I would do it later tonight.

[skliew64]

Thanks Rick.  We give you permission. 🙂 Greatly appreciated. 

Regards

Steve

[Mathias Moehl]

As Rick suggests, I would use mocha Ae for that. The most flexible approach is to do it in a stabilized Precomp that you can very easily create with my extension MochaImport+, as I show in this tutorial

The tutorial is quite old and both mocha Ae and MochaImport+ changed a lot since then. But I think it is still very useful to see how it can be useful in your situation. For details about using the mocha stabilized precomp workflow with the current Ae and mocha Plugin, see this tutorial:

https://mamoworld.com/tutorials/stabilized-precomps-mochaimport-v6-and-mocha-ae-plugin

[skliew64]

Hi Mathias, 

Thank you for your tips and tricks.  Could I please ask, which version of Mocha should I get and where. As there is now Mocha 2020.  Does Mamoworld includes Mocha when buying Mochaimport v6 ??

regards

Steve 

[Mathias Moehl]

For the workflows I show, all you need is MochaImport+ V6 which is available here

https://aescripts.com/mochaimport/

MochaImport+ does not include any version of mocha, but it works with any version of mocha - also the one that is bundled with Ae. The features I use in my tutorials are all available in the bundled version, so there is no need to buy a Pro version of mocha for these workflows.

[Mathias Moehl]

Also note that we have a bundle deal with Mocha Pro 2020:

If you buy a Mocha Pro perpetual license ($695) and at the same time buy MochaImport+ V6 (regular price $49.99) you get 5% off, which means effectively you only pay $13 on top to also get MochaImport+ V6.

I just noticed that the deal was still with Mocha 2019 on the webpage. I just updated it to 2020.

For details, see "Mocha Pro Bundle Deal" at the very bottom of the MochaImport+ product page.
https://aescripts.com/mochaimport/

But again, this only makes sense if you need some of the other features of Mocha Pro - the MochaImport+ functions don't require Mocha Pro and work in exactly the same way also with the Mocha plugin that is bundled with Ae.

[Roland Kahlenberg]

Mathias' MochaImport+ is an extremely powerful and useful tool if you're going to do a fair bit of tracking/VisualFX shots.

You already have good notes to follow. I just want to clarify this one thing -

You Wrote - " However, I notice that the blood patch, doesnt stay quite still. Possibly due to the movement from the camera."

I want to clarify that motion tracking an object in AE or mocha means tracking the movement of the object WITH or WITHOUT camera movement. The tracking algorithm DOES NOT know if the object being tracked is moving on its own, is static and all movement is from the camera or a combination of object and camera movement. Hence, any deficiency that you experience with your tracking result should be related to camera movement. You should pay more attention to how you are tracking the object and if you tracking options are optimally set for the task.

As Rick has suggested, it's not possible to provide definitive assistance without seeing the footage, looking at your tracking regions and how you've set up your tracking options.