Hello, I have created a 3D model in 3Ds max and I would like to improve it more by bring it into ZBrush But I am having problems.
I know how to export the model in a .obj and bring it into ZBrush. The problem is when I open it in ZBrush it is very pixelated. How can I make the model look more smoother? Keeping in mind I am still learning how to use ZBrush. If anyone could help that would be great thanks.
I suspect the model isn’t pixelated at all. You can’t pixelate geometry because geometry has no pixels. 
What I suspect is happening is that you’re zooming the canvas rather than scaling the model on the canvas. As a result, it’s like the zoom in Photoshop and the pixols on the screen are being enlarged.
On the right Shelf (to the right of the canvas) there is a column of buttons. The top ones are for zooming the canvas. The ones farther down for Move/Scale/Rotate are what you actually need. These manipulate the model on the canvas rather than manipulating the canvas itself.
If it’s a low poly model, it will also look faceted when you bring it into zbrush (almost as if every face has their own smoothing group). That’s just how the mesh gets drawn in zbrush, and doesn’t affect the true geometry (it’ll look smoother again if you export it back to Max, for example). Once you start subdividing it (ctrl+d, or Tools: Geometry: Subdivide), it will also begin to look smoother in zbrush as the faces get smaller and smaller.