Use a Clip 
to inspect your mesh or CAD, or results along intermediate surfaces in your mesh.
You can create a cutting plane or bounding box in the 3D Viewer, depending on which Clip Type you've selected:
Plane will retain the part of the volume on the side of the plane in the direction of the vector arrow. You'll need to set the Origin and Normal to determine the location and orientation of the plane, or use the widget in the 3D Viewer to drag the plane into the desired position. Clicking on the faces of the bounding box shown for the plane also allows you to adjust its rotation.
Box will retain the part of the volume inside the box. You'll need to set the Box Center and Length of each of the sides, and Rotation to determine the location, dimensions, and orientation of the box, or use the widget in the 3D Viewer to drag the box into the desired position.
Click the clip icon
in the visualization toolbar. This will open up the tool in the properties panel.Select a Clip Type.
(Optional) Select Invert to extract the region in the opposite direction from the plane as the normal vector, or the region outside the box.
(Optional) By default, the surface of the newly created clip region will follow the surfaces of each of the cells that intersect the cutting plane. If you're creating a clip of a CAD model, a smooth, flat clip surface is generated.
Click the check button to apply the settings.
Navigate to the Visualizations section of the control panel and select the Clip visualization that you just created.
Use the dropdown menus in the Display section to adjust the final appearance of the clip.
Note: You can create a Clip in the Setup tab and a Simulation tab.
In both cases, you can select whether to display the visualization as Points, Surface, Surface with Edges, or Wireframe.
In the Simulation tab, you have an additional Color By dropdown to choose the flow quantity to show on the surfaces of your visualization.