Vector Controls Reference

Line Integral Convolution Properties

Line integral convolution produces better-looking results, but is computationally more expensive.

Color Transparency

The contribution of the LIC image when blending with the surface color. Ranges are from 0 to 1: 0 for surface color only, 0.5 at which surface color begins to decrease, and 1 for LIC only (grayscale image). This property can be set with a slider. See Refining a Vector Display.

Line Thickness

Controls the granularity of the noise texture. Increasing line thickness beyond a certain point may not have an effect.

Line Length

Number of integration steps to perform during the LIC image generation. This property can be set with a slider. See Using a Slider.

Glyph Node Properties

The relationships among these properties and the relative or absolute length of the vector glyphs are outlined in the table following the property descriptions.

Vector Spacing

Defines how the vectors are distributed. Geometric spacing places a vector glyph at the vertex or at the centroid of each cell face in the mesh. This type of spacing is well suited to cases where there is little variation in mesh cell size. Uniform spacing places a vector glyph at each intersection in a user-specified uniform grid that lies in the plane of the screen, and is particularly useful when the mesh has a large variation in cell size.

• Geometric—vectors are placed on cell faces, and the density of the vectors can be controlled by changing the On Ratio and Randomize properties.
• Uniform Screen—vectors are placed at each grid point on a uniform grid that lies in the plane of the screen. The density of the vectors can be controlled by changing the grid dimensions with the N Grid Points property.

Vector Scale

Defines how to scale the vectors.

• Absolute—scales the vectors based on a specified length in the Glyph Length property of the Absolute Length node.
• Parts Size—scales the vectors relative to the size of the parts in the Glyph Length property of the Relative Length node.
• Screen Size—scales the vectors relative to the display size in the Glyph Length property of the Relative Length node.
• Direct—scales the vectors based on a proportion specified in the Glyph Length property of the Direct Length node.

  The Direct Length feature allows you to define a vector scale as a function of velocity. In this manner you can create animations where the vector length is consistent between frames, and also compare similar simulations with different maximum velocities.

Vector Length

Choose between relative and constant.

• Vector Magnitude—uses relative vector magnitude, that is, the scales of all vectors are fractions of the largest one.
• Constant Length—lets you scale vectors on the order of the model rather than on the data.

Vector Style

Defines how the vector are displayed.

• 2D Wireframe—a simple line.
• 2D Filled—a line with finite diameter.
• 3D Head, 2D Tail—conical head.
• 3D Head, 3D Tail—conical head and tail with finite diameter.
• Cone—cone only.
• Sphere—sphere only.

Glyph Tip Scale

Sets the scale of the glyph heads.

Constant Tip Size

When activated, causes the head of the arrow in the vector displayer to be scaled equally for all arrows independent of the underlying velocity function.

Although the Relative Length, Absolute Length and Direct Length nodes seem to have the same Glyph Length property, entries are retained separately for each combination of settings that are listed in the table above. For example, if your entry for Glyph Length with an Absolute vector scale causes the glyph to appear visibly longer than it did with a Parts Size (relative) vector scale, and then you switch back to Parts Size, you see the glyphs revert to their earlier size.

Relative Length Properties

Glyph Length (%)

Specifies the length of the largest glyph or all of them as a percentage of parts size or screen size. (See preceding table.)

Properties of Absolute Length and Direct Length

Glyph Length

Specifies the length of the largest glyph or all of them as a specific value or a proportion of a unit. (See preceding table.)

Units

Selects the type of units to use.

Geometric Spacing Properties

Randomize

Determines whether the pattern of vector glyphs is defined by the mesh grid. When activated, ignores the structure of the model, including differences in density of the grid. This can result in a better distribution of vectors if the mesh is highly unstructured or has great variation in cell surface area.

On Ratio

The number of cells that display a single vector quantity. You can use this function to control the density of vectors, and thereby study broader or narrower patterns. At the default setting of 1, every cell displays a vector. Higher settings cause fewer vectors to be displayed. The value must be an integer.

Glyph Location

Sets the location of the vector glyphs. By default, the location of glyphs is the same as their native data location, but you can reposition the glyphs with this property. The native data location can be the cell face centroid or the vertex, depending on the type of field function and the part that is assigned to the displayer. For example, Position is a natively vertex-based field function, while Vorticity is cell-centroid based.

• Cell—sets the glyph location at the cell face centroid.
• Vertex—sets the glyph location at the cell vertex.
• Native—automatically uses the native data location, which depends on the assigned field function and the displayer part.

Vector glyphs are cell-centroid based by default when their native data location cannot be determined, due to either of the following causes:

• The input parts of a derived part exhibit conflicting native data locations.
• The internal field function definition is ambiguous or undefined.

Note	Certain parts only allow vertex-based vector glyphs: feature lines, streamlines, and isosurfaces.

Uniform Spacing Properties

N Grid Points

Specifies the u and v values of the grid, where u is the number of grid points in the horizontal direction and v is the number of grid points in the vertical direction.

Zooming in does not affect the grid size.

The uniform grid is linked to the size of the scene display, so shrinking the window increases the glyph density, and enlarging the window decreases the glyph density.