Fluent and EnSight use slightly different terminology, that can trip you. In this case, Contours is to be considered a false friend word.
In order to see the distribution of a variable on a 2D part, in Fluent you create a Contour. This is a new part, and is always shown with the distribution of the variable that has been used for its creation.
In EnSight, if you want to see the distribution of a variable on a part, you can change the "color" attributes of the part itself to be colored by that variable. This operation will not create a new part, since the "color by" is considered an attribute of the existing part and not a new part all together. You can change the variable you're using to color by any time.
EnSight also contains a Contour feature. This is not the same as the Fluent Contour. When you create a Contour in EnSight, this creates a new part that consists on the iso-bar of the variable: 1D lines that show where the variable has a set value.
Example 1.1: Contour Feature
Launch EnSight and, from the Welcome window, select the AMI Dataset example session. Select part 1 in the part list, right-click on it and select → . This will create a new part with ID = 3, called Clip_plane. This is a slice in the X direction of the 3D domain.
Now, select this new part in the part list, right-click and select Scalars). You will see that now the part shows the distribution of this variable, but no new parts are created in the part list.
→ . In the pop up menu that appears, select the variable pressure (under
You can right-click again on part 3 and set it this time to be colored by the vector variable velocity.
Note: Notice how, also this time, a new part was not created. This is because the color-by is considered an attribute to a part, not a new part.

The min. and max. of the velocity palette are automatically set to the min. and max. of the variable at the current timestep on the entire model. Right-click on the velocity legend in the Viewport → → . This will change the min. and max. values to create a better visualization.
Finally, we can create a Contour part and see what this is in EnSight. Right-click on the Clip_plane part in the part list and select → . In the editor that opens, set as the Variable velocity, and hit the button at the bottom of the widget.
Note: A new part will appear on the part list: the Contour part.
Right-click on the Contour part and select → . Some black lines will appear on the clip. These lines represent the path along which the velocity has a constant value. If you hide the Clip_plane part (right-click on it and select ), you can see that the Contour part is only these lines.
