Adding smoke to live action?

[sean_brown]

Hi there,

What would be a rough outline workflow of how to go about adding smoke from Phoenix from Maya to live action? I wanted to have smoke emanating from a persons hand.

Thanks

[georgi.zhekov]

Hey,

In order to make such a shot, the workflow is as follows:

- You need to track your live action plate in a 3D tracking software (this process is also known as match-moving). This will generate some 3d helpers and possibly a camera in 3D space. Then you need to export this in a suitable format so that Maya can read it.
- Import the tracking data and the camera in Maya and create an emitter object that matches the movement of the person's hand from your live action plate.
- Create a Phoenix simulator in your scene that covers the area where the simulation would happen. Then use the emitter object you created in the previous step and add it in a Phoenix source that will emit smoke.
- After the simulation is done - render it in a way that the emitter object you have is a matte object (meaning that it will be invisible to the camera, but it will still cast and receive shadows). This way the smoke can integrate better in your shot.
- Composite the smoke renders over your live action plate in compositing software.

Hope this helps!

[sean_brown]

Hey,

In order to make such a shot, the workflow is as follows:

Hi Georgi, this is very helpful. Would you know of any online tutorials or courses that would help me further in more detail for this type of task? Do you have a preferred match moving program? I have After Effects and I can use Nuke Non-Commercial version.

Thank you so much

[fixeighted]

This is potentially either easy or difficult, depending on the shot - so whether it's just the hand/s that move, or both the hands and the camera.

Nuke apparently does not have an 'object tracker', so you'd need some software that does (depending on the complexity of the hand movement).
Syntheyes is a very good option, as is PF Track, but both are quite expensive unless you plan on doing this regularly on lots of different projects.

That said, you could very possibly get away with manually keyframing the reference object that you'll use to link the Phoenix sim to.
So for example, if you want smoke to simply come from the palm of the hand, then you only need a plane to follow the relative plane of the palm, which is fairly easy.
If you wanted the smoke to interact with the e.g. moving, curling fingers of a hand, then that is the other extreme. Both would need a hand model, either animated or not.
You could in this situation either do it accurately or fudge it a bit, relying on the smoke to cover any errors.

[georgi.zhekov]

I'm afraid I can't recommend any specific course or a tutorial, but I think there are some videos on YouTube that might help with the process.

As fixeighted mentioned it all depends on the shot you're after and maybe you can get away with a simple keyframing of the emitter object and skip the additional software.

[sean_brown]

This is potentially either easy or difficult, depending on the shot - so whether it's just the hand/s that move, or both the hands and the camera.

Nuke apparently does not have an 'object tracker', so you'd need some software that does (depending on the complexity of the hand movement).
Syntheyes is a very good option, as is PF Track, but both are quite expensive unless you plan on doing this regularly on lots of different projects.

That said, you could very possibly get away with manually keyframing the reference object that you'll use to link the Phoenix sim to.
So for example, if you want smoke to simply come from the palm of the hand, then you only need a plane to follow the relative plane of the palm, which is fairly easy.
If you wanted the smoke to interact with the e.g. moving, curling fingers of a hand, then that is the other extreme. Both would need a hand model, either animated or not.
You could in this situation either do it accurately or fudge it a bit, relying on the smoke to cover any errors.

syntheyes seems reasonably priced.I would consider that as an option. When you mention keyframing the reference object, is that done in Maya by importing the video footage or is that done in a compositor first and then exported/imported into maya?

[fixeighted]

Syntheyes is very good, so a great investment.
For this particular project, if it's simpler to keyframe it for whatever reason then yes, you load an image sequence to Maya and then position
your hand model and match its movement as well as you can to that of the clip.

You actually could get a good headstart by using this to process an initial bit of mocap data https://www.deepmotion.com/animate-3...hoC2VUQAvD_BwE
Whilst it won't pick up every finger detail it will be good enough for position/rotation. And its free trial is more than enough to get what you need I think.