Examples of the General Extrusion Operator


The General Extrusion operator maps expressions defined on a source to an expression that can be evaluated on any destination geometry where the destination map expressions are valid. It can be used for a variety of different purposes, examples of which are presented here.

Extruding Data Along a Direction

Given an expression defined on a plane, e.g., the xy-plane, it is desired to map this data along the z direction.

To implement, define a General Extrusion operator on a boundary parallel to the xy-plane, with the z-expression blank for both the Source Map and a Destination Map. The General Extrusion operator will map data from the boundary into the volume, along the z direction, as shown in the following screenshots.

A transparent cube with one side visualizing simulation results in a rainbow color table, next to a cube with the same data mapped onto each side. Mapping of data defined on a boundary (left) along the direction normal to the plane and into a volume (right).

A screenshot of the Settings window for the General Extrusion operator, with the Source Selection, Destination Map, and Source sections expanded.
Settings used to map data from a boundary parallel to the xy-plane along the z direction.

It is also possible to define the mapping in terms of coordinate systems. For example, to map data from a boundary around a centerline, introduce a cylindrical system, and use those coordinate system variables to define the source and destination map.

A transparent, curved cylindrical model with simulation results on one boundary, next to the same cylinder with the data mapped on all boundaries. Mapping of data defined on a cross section (left) around an axis of symmetry and into a volume (right).

A screenshot of the Settings window for the General Extrusion operator used to revolve data about an azimuthal axis of a cylindrical model.
Settings used to revolve data about the azimuthal axis of a cylindrical coordinate system.

Transforms: Translate, Rotate, Mirror, Scale

A visualization of sample data defined on the xy-plane, plotted with a rainbow color table.
Sample data defined on the xy-plane, centered at the origin.

Considering a variable defined on the xy-plane within a unit square centered at the origin, as shown above, it is possible to implement a variety of transforms simply via different destination maps, and leaving the source map unchanged. Several cases are illustrated in the table below. The same transforms can be implemented in three dimensions.

Type of Transform Destination Map Result
Translate x-expression: x-0.3
y-expression: y-0.15
An image of sample data on the xy-plane after undergoing the Translate transform, with a black arrow in the bottom-left corner.
Rotate x-expression: x*cos(30[deg])-y*sin(30[deg])
y-expression: x*sin(30[deg])+y*cos(30[deg])
An image of sample data on the xy-plane after using the Rotate transform.
Mirror x-expression: x
y-expression: -y
Sample data plotted on the xy-plane after undergoing the Mirror transform, plotted with a rainbow color table.
Scale x-expression: x*2
y-expression: y*3
A small square of rainbow sample data on a larger white background.

Other Uses of the General Extrusion Operator


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