[Astonisher]

Hi Carlos,
I haven’t had too much experience with Trapcode Particular but I just figured answers out to both of your problems within about 15 minutes of experimenting around.
In advance I set all my layers to 3d for this project, so I could manipulate them the way I wanted to better control where I see the shadows, light, etc.

As far as generating shadows goes you have to create a new light, I set mine to Spot. Then, go to the layer that you have your Trapcode Particular effect applied to and click the arrow next to the layer to show Effects/Transform/Material Options and then click Material Options and turn Casts Shadows on. That should take care of the shadows.

Create a layer that you want to use as your floor or wall, in other words where you want your generated particles to stop at. This layer can be set to hidden layer, so you don’t see it. I created a simple layer in 3d and moved it so it was like a floor.
Then, all you have to do under the Trapcode Particular Effect settings is go down to Physics and set the Physical Model to Bounce.
Set your floor layer to the layer you created that represents a floor/wall and it should then stop at that wall.
Collision Event may be the most important setting here as it tells the particles what to do when it hits the wall.
Bounce makes the particles bounce back up if your gravity is set going down as mine was.
Slide makes the particles slide across the layer once they hit it.
Stick makes the particles stick to the layer when they collide with it.
And last but not least Kill makes the particles disappear or die when they hit the layer.
Hope that helps you out. If that doesn’t work the way you expect it to and/or you have any other questions with it feel free to post back.

Good luck,
Zack

[Astonisher]

I think that having a moving shot in a car with a moving background will be very hard if not impossible to match up, especially if it’s multiple shots. What I would try and do is get a static shot of the car, and then get greenscreen footage of just the passanger/driver and then insert the street footage you took on one layer, with the static car shot on top of that and then a layer with the driver keyed out so the car doesn’t have much movement interior wise. But the person will be moving inside of it, assuming for instance if its like an over the shoulder shot with the car interior and then the person inside you’d be able to mask out the window for your background footage you’re bringing in and that should work fairly well. As far as movement goes if you took a few good pictures of the interior or of different parts, i.e. back of seat, dashboard, steering wheel, rear view windows and aligned them in 3d space correctly you’d be able to have realistic movement inside of the car with the passanger. It’s a tough one though, but maybe someone else can answer it better. Either way good luck and hopefully if the blue screen is yours you can try it out and experiment with different techniques.

Later,
Zack