I've been having trouble with this effect for a long time so I finally decided to bite the bullet and ask some of the geniuses on here.
from 0:12 - 0:25 on this video you can see the 3D grid that the cars are driving on and the camera is following the cars.
I've tried to make a large solid with a grid effect applied, rotating it in 3D space and animating a camera to follow the "road", I've also tried keeping the camera in the same place and animating the grid but there are always issues.
issue 1) the "road" isn't long enough, I'd like to keep this shot going for 20 seconds or more.
issue 2) the camera starts off with the "road" above it for some reason, then it goes through and then it has the correct orientation.
The main idea is that I want to have the camera follow a particle trail on top of the grid, similarly to how the camera is following the cars on the example.
It looks to me as if the texture map on the road is animated, and that the road isn't really that long - also the "lights" on the sides of the road. Bear in mind that this is true 3D, from what I can tell - although it's really cheesy 3D. You might try creating an animated grid - there's a native grid plugin in AE. Just keyframe the motion, and you'll be a lot closer to what you're looking for.
Is that the correct native grid? Would I need to animate the parameters within the effect or the solid that the effect is placed upon?
I have Video Copilot's Element 3D plugin, not sure if that allows you to animate the texture maps though.
One thing I thought to try was to move the solid forward while cutting off the parts that are out of shot behind the camera and extending the solid at the same time to make it seem like a long road, not sure if that would make it seem continuous though.
Generate/Grid should work fine - if you want to be able to use an animation in Element 3D, just create the layer and animation, then set up Element 3D to use a custom layer as a texture map - it sounds as if you need to go over the Element 3D tutorials. It's not rocket science, but it's not intuitive either.