XMarkerSamplePattern

MLModule

genre	Marker
author	Ola Friman
package	FMEwork/ReleaseMeVis
dll	MLXMarkerUtils
definition	MLXMarkerUtils.def
keywords	xmarker, pattern, resample, sphere, circle, mpr, vessel, centerline, points

Purpose

The module XMarkerSamplePattern samples a circle or sphere pattern in 3D around an input position given by an XMarker.

The samples are returned as XMarkers in an XMarkerList. The module was originally written to sample the cross-sections and regions around a vessel.

Usage

The minimal input to the module is an XMarkerList with one XMarker.

When the input XMarkerList contains more than one XMarker, an Input XMarker Index to Use must be chosen.

Details

For calculating the normal vector of the circle, a Neighbor Difference mode is available. In this mode, the normal vector is calculated as the forward difference, i.e., n_i = x_i+1 - x_i, of the input XMarkers. For the last XMarker in the input list, a backward difference is used.

For the sphere pattern, predefined sample directions are defined. These directions were obtained using tessellations (0-, 1-, 2-, 3- and 4-fold) of an icosahedron. If v is a direction in this set, -v is also a direction. The mirrored directions are stored interleaved in the output XMarkerList, i.e, if v is stored at index 0, -v is stored at index 1.

Windows

Default Panel

Input Fields

inputXMarkerList

name: inputXMarkerList, type: MLBase

Output Fields

outputXMarkerList

name: outputXMarkerList, type: MLBase

Parameter Fields

Field Index

Auto update: Bool	Samples for Circle Pattern: Integer
End Angle: Double	Samples for Sphere Pattern: Enum
Input XMarker Index to Use: Integer	Start Angle: Double
Message: String	Update: Trigger
Normal Calculation: Enum
Output Representation: Enum
Pattern Type: Enum
Radius: Float

Visible Fields

Samples for Circle Pattern

name: nbrOfCircleSamples, type: Integer, default: 20

Sets the number of samples when the pattern is a circle.

Samples for Sphere Pattern

name: nbrOfSphereSamples, type: Enum, default: 42

Defines the number of samples to generate for a sphere pattern.

Only a predefined number of directions is available.

Values:

Title	Name
12	12
42	42
162	162
642	642

Output Representation

name: representation, type: Enum, default: Points

Defines how the sampled pattern is represented in the output XMarkers.

Values:

Title	Name	Description
Points	Points	The samples are represented using the point positions in the XMarkers.
Vectors	Vectors	The vectors from the middle point to the samples on the patterns are stored in the XMarkers. See the image below for an illustration. Note that the circle pattern in general is in 3D; the examples below were created with a normal direction of (x,y,z) = (0,0,1).

Radius

name: radius, type: Float, default: 5

Sets the radius of the pattern.

Start Angle

name: startAngle, type: Double, default: 0

Sets a starting angle for the pattern.

End Angle

name: endAngle, type: Double, default: 3.14159265358979

Sets an ending angle for the pattern.

Pattern Type

name: patternType, type: Enum, default: Circle

Defines the pattern type.

Values:

Title	Name
Circle	Circle
Sphere	Sphere
Circle Sector	Circle Sector

Normal Calculation

name: normalCalculation, type: Enum, default: NeighborDifference

Defines how the normals should be calculated.

Values:

Title	Name	Description
Neighbor Difference	NeighborDifference	The normal to the circle plane is calculated as the difference between successive input XMarkers.
Internal Vector	InternalVector	The vector in each XMarker is used as normal (the vector must exist).

Input XMarker Index to Use

name: inputXMarkerIndex, type: Integer, default: 0

Sets the index of the input marker to use if more than one marker is present.

Message

name: messageString, type: String

Shows a message about the state of the module.

Update

name: updateButton, type: Trigger

If pressed, the module computes anew.

Auto update

name: autoUpdateToggle, type: Bool, default: TRUE

If checked, the module computes anew on any parameter or input change.