Data Type: Analytic Scalar Field ()

Description:

This data class represents a user-defined 3D scalar field based on an arithmetic expression. It provides a port Expression by which an arithmetic expression depending on Cartesian coordinates x, y, z can be entered that defines the value for each point in space. The range of values with respect to the unit cube (default) domain is indicated as Component Range. A data object of type AnnaSccalarField3 has three additional input ports that can be connected to other data objects representing 3D fields, e.g., to image data objects. The predefined variables a, b and c are available for referencing such connected data objects in the arithmetic expression, this way a scalar field depending on other fields can be defined. Whenever an expression evaluation is triggered to compute the value for a point (x,y,z), the variables a, b and/or c will be be substituted by the corresponding input values at the same point (x,y,z). For instance the value at a single point may be obtained by attaching a Point Probe module to the Analytic Scalar Field data object and entering the point's coordinates by the Coord port of that module.

If inputs contain undefined values, each of them will be used during the expression evaluation. If an undefined value is found, 0 will be used during this evaluation instead of the real undefined value. Therefore, the undefined value isn't propagated to the result.

An expression consists of variables and mathematical and logical operators, the syntax is basically the same as for C expressions. The following variables are always defined:

• x: the x-coordinate of the current point
• y: the y-coordinate of the current point
• z: the z-coordinate of the current point

If data objects Field A, Field B or Field C are connected to port InputA, InputB and InputC respectively, the following variables are also defined:

• a: the values of input object A
• b: the values of input object B
• c: the values of input object C

The same C style mathematical and logical operators as well as built-in functions that are available for arithmetic expressions can be used here, see Arithmetic module description.

Connections:

InputA [optional]
Optional scalar field.

InputB [optional]
Optional second scalar field.

Ports:

Shared colormap

In case a colormap is connected to the scalar field, this colormap will be shown here. If no colormap is connected, only the Edit menu is visible. To connect, disconnect or change the colormap, use the Edit menu or, equivalently, the popup menu under the right mouse button. See also Colormap and PortSharedColormap.

Expr

Input field for arithmetic expression defining the scalar field values.

Domain

This port is only visible if other fields are connected as input a, b or c. These input fields might not be defined everywhere. If set to unrestricted the field can be evaluated everywhere, a value of 0 is used for the input fields of a, b or c if evaluated outside their domain. If set to dependent field, the field is only evaluated inside all domains of the dependent fields a,b and c.