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kofman
02-02-2003, 02:20 AM
I'm working with live footage and trying to apply a special effect into the footage.

What I've Done so Far:
- Got the footage converted into avi
- Dropped it into a polygon plane as a texture
- and synched the timeslider with the footage

So I can now watch the footage on the plane.

The Scene:
- A girl walks up to a chalk board in school
- The chalk board has a large problem written on it
- She reaches to begin writing the answer
- The moment her chalk touches the black board the writing begins to swerve off the chalk board and around her body and into her eyes

My Plan:
- Make a 3D matte object to cover the chalk board from the live footage and replace it with a fake one which will release particles in form of writing which will the turn into something that looks like smoke and then go into her eyes. The particles would fly through the plane and would need to be controlled. Maybe attached to a curve.

The Problem
- Since her arm is reaching for the chalk board it makes it hard to create a 3d matte object over the chalkboard. So how would I do this if every frame is different?

- The second part is the particles part. I'm not quite sure on how to get particles to flow along a curve and look like smoke. In fact I've done very little work with particles before becides basic emmiters like car exhust, rocket exust and so on.

Please help me out as soon as possible. This is an urgent project. :shrug:
mark_wilkins
02-02-2003, 04:26 AM
If you just want the particles to go behind the arm, all you do is use whatever compositing package you're using to animate a matte that cuts the arm out of your particle render, then put the particle render on top of the background image.

-- Mark
kofman
02-02-2003, 04:29 AM
I see but how do I create a matte that changes every frame. Do i have to do it manually?:scream:
mark_wilkins
02-02-2003, 04:51 AM
yes. You can either animate it in 2D or you can model, rig, and animate a 3D stand-in for the arm. For a short shot the 2D approach is almost certainly less work.

-- Mark
kofman
02-02-2003, 04:54 AM
yea I guess the quickest way is to actually do it manually. I don't have enough time to start matching and rendering textures in order to remake the arm. But thank you very much.

How do you recomand I should make a fluid milk/smoke type of particle effect?

I have 4.0 not 4.5
mark_wilkins
02-02-2003, 05:04 AM
Textures? I wasn't suggesting texturing anything.

If you're just rendering a matte you don't need to texture anything. Just give the arm a flat black color and render an alpha pass only.

However, animating the matte in 2D is still probably easier unless you're doing something that requires a 3D holdout (like volumetric particle rendering.)

As for how you get the look you need for the particles, it's kind of hard to know how to help you with that.

-- Mark
kofman
02-02-2003, 05:54 AM
thanks man, I'll experiment and try to get it
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