What is the easiest way to make curved grid like this in 3D.

In 2007 I wrote an article on using displacement maps that were animated using point lights as a light source with positive and negative intensity values to get mirrored displacement from positive and negative red and green values created by the lights. The result looks like this:

I have uploaded an updated project file for you to play with. This is what the Displacement Map comp looks like:

If you have a budget for a plugin, I suggest Freeform Pro from AE Scripts. You can even add Projection Mapping to a Freeform layer to distort any type of image. Here's an overview of the plugin:

I use both techniques. One is easier than the other for some designs. The other is more efficient for different scenarios. It all depends on the project. If I knew what you were trying to accomplish, I could give you some more efficient suggestions.