# Define Curves

Edit existing curves or add new curves to the current plot.

The Define Curves panel also contains HyperGraph 3D's curve calculator.

## Create and Define Curves

To edit a curve, select it from the Curve list or from the plot window.

If you select Source > Math, the X, Y, Z, U, and V vectors are displayed in the Expression = field. Under Vector, select All or an individual vector to view and modify.

New data can be selected from a source file, mathematically defined using the program's curve calculator, or entered as values. The Define Curves panel options change depending on which source is selected.

Click Apply to define the curve(s).

## Curve List

The curve list displays the names of all the curves in the active window.

Curves can be renamed, added, cut, copied, and pasted using the curve list controls.

If you select a curve from the list, its name is displayed in the text box above the list. Individual curves can be turned on or off.

The Cut, Copy, Paste, and Add buttons are used to maintain the curve list for the active window. Curves can be copied and pasted into other windows. Curves can also be added and deleted from the list.

From the Curve Type menu, select the type of curve that you want to define.
Line
Display, add or edit 3D line curves.
Surface
Display, add, or edit surface curves.
Waterfall
Display, add, or edit waterfall curves.

## Vector

Select the X, Y, Z, U, or V curve vector from the list.

Click All to display the All dialog and edit each curve vector.

## Source

Curves are comprised of X, Y, Z, U, and V data vectors. Vectors for 3D line curves can be defined from files, math expressions, or the values table. Waterfall and surface plots can only be defined from math expressions. The vectors of a curve do not have to come from the same source. For instance, the data source for the X vector of a curve can be an ASCII file and the source for the Y vector of the same curve can be defined by an expression, such as sqrt(x).
File
When selected, the file options are displayed, allowing you to select data files for the X, Y, Z, U, and V vectors.
Math
When selected, the curve calculator is displayed, allowing you to define the vector mathematically.
See Curve Calculator for more information on defining vectors mathematically and signal processing.
Values
When selected, the Values table is displayed, allowing you to directly enter data point values.

You can cut, copy, paste, and insert data point values to the table. Click the expansion button, , to view a larger dialog containing all data points.

## Referencing Curves

Expressions can reference any curve or vector in the current session. Curve vector references can be defined by picking the curve with the mouse or by using the following syntax:

pmwnco.vector

where:

m is the number of the page on which the curve resides

n is the number of the window which contains the curve

o is the number of the curve in the window

vector indicates the X, Y, or time vector of the referenced curve

For example, p2w1c3.y references the Y vector (.y) of the third curve (c3), in first window (w1), on the second page (p2).

When a referenced curve is edited or updated, the curves that reference that curve are updated as well.

The Curves dialog allows you to view the curves on a particular page within a session.