# fracture import command

Syntax

fracture import keyword ...

Primary keywords:

Import fractures.

Note

• A model domain must be specified prior to importation, and all fractures must fall completely within the model domain unless the skip-errors or truncate keywords are given.
• The main characteristics of the DFN (e.g., center, spatial extent, etc.) can be investigated prior to loading with the fracture compute command.

Fractures can either be imported from a file (see the file keyword ) or a geometry set (see the geometry keyword). Fractures cannot be imported into existing DFNs. If a DFN is not specified then one is created with the next available ID and automatically named based either on the file name specified or the geometry set name. In addition to the fractures geometries, the DFN can be associated with a fracture generation template via a fracture generation template file (see template, fracture template create and fracture export for further details). Fracture properties can also be assigned via a property file (see property-file and fracture export for further details).

center

The DFN will be “centered,” wherein the average location of the fracture centers is aligned with the origin. This location is taken for all fractures prior to modification (e.g., truncation or omission).

clean

Specify that the geometry set, from which fractures have been imported, is to be deleted after successful importation. This keyword only applies when the from-geometry keyword has been specified.

dfn s

Specify the DFN name to be created. If a name is not specified then the DFN name is derived from the import file name or geometry set name specified.

dfn-dominance i

The DFN dominance is set to i where i ≥ 1. The dominance is used during contact model assignment when a contact intersects multiple fractures from different DFNs. The fractures from the DFN with the lowest DFN dominance will be further scrutinized by their individual dominance values to assign the appropriate contact model properties. If not specified, then the next available dominance is used. See the fracture contact-model command for further details.

dominance keyword

Specify the mode to set the fracture dominance. Should a contact intersect numerous fractures from a single DFN, then the fracture with the lowest dominance is used to assign the appropriate contact model properties. The default behavior is ordered. See the fracture contact-model command for further details.

ordered

The fracture dominance in assigned based on the order of importation, where the dominance values increase as importation continues.

random

Specify that the fracture dominance is set in a random fashion, independent of the order of fracture importation.

from-file s1 <format keyword>

Import fractures from file s1. The format can optionally be specified with the format keyword. If no format is specified, then the file extension of the name specified with the file keyword is used to determine the file format. A ‘.dat’ file extension is assumed to be in the itasca format, a ‘.flab’ file extension is assumed to be in the fishlab format, and a ‘.fab’ file extension is assumed to be in the fracman format.

itasca

The itasca format is as specified in DFN-Related File Formats, and is the default format.

fishlab (3D ONLY)

The fishlab format is the flowplane format used in FISHLab.

fracman (3D ONLY)

The fracman format follows the FracMan ASCII output format.

from-geometry s

Import fractures from the geometry set s. In 2D, the geometry edges are queried and turned into fractures. In 3D, this command attempts to import fractures as both planar polygons and disks. Planar polygon importation scans the geometry polygons. Disk importation occurs by scanning all geometry points and investigating the extra variables. If there are 3 extra variables that are doubles in extra slots 1, 2 and 3, then the point is deemed to represent a disk where the extra variables are the radius, dip (in degrees) and dip direction (in degrees), respectively.

make-disk i (3D only)

Fractures with i vertices or more are made into disks with radii equal to the average distance from the centroid to the vertices and dip/dip direction, as specified.

make-planar (3D only)

Planarity is forced for all fractures that are not disks. The fracture normal is as defined in the data file, and the fracture position is set to the average position of the vertices. The vertices are adjusted so that they fall on the plane.

offset v

Offset all fracture locations by v.

property-file s

Indicate that the properties of fractures are set via a property file. See DFN-Related File Formats for a definition of the property file format. This cannot be used with the geometry keyword.

skip-errors

Indicate that the importation will continue in spite of fractures lying outside the model domain. The offending fractures will not be imported.

template-file s

Indicate that the provided DFN has been generated according to the fracture generation template defined in the file s. The template file format is specified in DFN-Related File Formats. This cannot be used with the geometry keyword.

truncate

Indicate that fractures intersecting the model domain boundary are truncated (i.e., disk fractures in 3D can be converted to polygonal fractures).

Usage Example

The following example illustrates how the fracture import command can be used to import a DFN linked with a template and two property sets (files generated with the example in the fracture export command). The DFN here is truncated in a smaller domain than the domain of generation.

model new
model domain extent -4 4
;Import fractures from a file
fracture import from-file 'example.dat' format itasca ...
property-file 'example_prop.dat' ...
template-file 'example_temp' ...
dfn 'dfn_import' truncate
program return


The following example illustrates how the fracture import command can be used to create a DFN of disks by using geometries (3D). First, geometrical nodes are created and extras are associated to them (extra 1 is size, extra 2 is dip and extra 3 is dip direction). These nodes are transformed into disk-shaped fractures with the fracture import command. The truncate keyword is used to truncate the new fractures at the system limits.

model new

model domain extent -5 5
;Create geometry with extra variables corresponding to disks
;First us radius, then dip, then dip direction
geometry set 'disks'
geometry node create (-4,-4,-4) extra 1 1.0 extra 2 90.0 extra 3 270.0
geometry node create (-3,-3,-3) extra 1 1.5 extra 2 85.0 extra 3 250.0
geometry node create (-2,-2,-2) extra 1 2.0 extra 2 80.0 extra 3 230.0
geometry node create (1,1,1) extra 1 2.5 extra 2 75.0 extra 3 210.0
geometry node create (2,2,2) extra 1 3.0 extra 2 70.0 extra 3 190.0
geometry node create (3,3,3) extra 1 3.5 extra 2 65.0 extra 3 170.0
geometry node create (4,4,4) extra 1 4.0 extra 2 60.0 extra 3 150.0
;Import these fractures from the geometry set
fracture import from-geometry 'disks' dominance ordered ...
dfn 'from_geometry' truncate
program return


The following example illustrates how the fracture import command can be used to create a DFN of polygons by using geometries, and automatically calculate intersections. The polygons are directly created with the geometry logic, and transformed into fractures with the fracture import command. The clean keyword is used to delete the geometry once fractures are created.

model new

model domain extent -5 5
;Create geometry as polygons
geometry set 'polygons'
geometry polygon create by-positions  (-4,-4,-4) (-4,4,-4) (4,4,-4) (4,-4,-4)
geometry polygon create by-positions  (-3,-3,-3) (-3,3,-3) (3,3,-3) (3,-3,-3)
geometry polygon create by-positions  (-2,-2,-2) (-2,2,-2) (2,2,-2) (2,-2,-2)
geometry polygon create by-positions  (-1,-1,-1) (-1,1,-1) (1,1,-1) (1,-1,-1)
geometry polygon create by-positions  (-4,4,-4) (-4,4,4) (4,4,4) (4,4,-4)
geometry polygon create by-positions  (-3,3,-3) (-3,3,3) (3,3,3) (3,3,-3)
geometry polygon create by-positions  (-2,2,-2) (-2,2,2) (2,2,2) (2,2,-2)
geometry polygon create by-positions  (-1,1,-1) (-1,1,1) (1,1,1) (1,1,-1)
;Import polygons as fractures
fracture import from-geometry 'polygons' clean dominance ordered ...
dfn 'from_geometry' truncate
program return