Model Faults

To access this dialog:

  • Activate the Geology ribbon and select Surfaces | Faults.
  • Run the command model-faults
  • Use the quick key combination "mfa"

Fault Modelling Overview

The Model Faults tool automatically generates fault wireframes from loaded fault trace data.

A fault trace is a string that represents the profile of a fault at a landmark position. Faults can be constructed using one or more traces. Higher trace numbers tend to produce more convoluted wireframe fault data. Digitize fault traces directly into an active 3D window, and modify existing traces by extension and/or reversal.

The tool utilizes loaded trace data to form wireframe sheets through extrusion. This extrusion can be controlled either as a general value for all fault traces, or individually per fault trace, or a combination whereby individual fault trace dip and dip direction can set, whilst falling back to the default fault-level orientation if not specified.

Once fault data has been generated, edits to precursor fault traces can either be performed as a batch, then applied to regenerate all affected fault wireframe data, or wireframes will update in real time as traces are edited.

This command assumes the following:

  • A dip of 90 degrees is vertical, 0 is flat

  • A dip direction of 0 is to the north and clockwise, e.g., 90 degrees is east.

  • Faults can have a relationship to each other, where a fault terminates on another, formating a fault 'block'

  • Faults terminate at some point, they don't carry on indefinitely.

  • A fault can comprise one or more fault traces.

  • A fault trace is a distinct string entity, comprising a start and an end vertex.

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Fault/Trace Dip & Dip Direction

During fault modelling, loaded string data is appended to create fault trace data. First, a fault container object is specified, then traces are added to it. A fault object can contain one or more fault traces.

Selecting a Fault ID in the faults table automatically updates the traces tables below. A mean fault Dip and Dip Direction displays for each fault.

Trace data can also be created directly within the Model Faults tool.

Trace data will always include two attributes to represent the Dip of the trace and the Dip Direction. Where a single fault trace is extruded to form a fault sheet, the dip is 90 (vertical) by default, and the dip direction is calculated according to the average dip direction of each edge of the trace object.

Where multiple traces are linked together to form a fault sheet with more complex directional changes across its surface, the dip and dip direction of each trace edge are calculated automatically.

Note: If it is not possible to construct a fault due to the arrangement of fault trace strings or impossible fault dependencies, feedback is provided as a tooltip in the faults or traces table. Failed faults or traces are highlighted with a "!" symbol, e.g.:

Implicit Modelling Metadata

All implicit modelling commands generate or utilize input data. Data generated by animplicit modelling command is automatically appended with a _SOURCECOMMAND attribute that denotes the function from which it was created.

The _SOURCECOMMAND attribute contains one of the following valid values:

  • FaultModelling - Fault traces (strings) are updated.

  • VeinFromSamples - Boundary strings, additional points and fault wireframes are updated.

  • ContactSurface - Boundary strings, additional points and fault wireframes are updated.

  • GradeShell - Ellipsoid data is updated.

  • Categorical - Ellipsoid data and additional points are updated.

When data is used by a command to generate its output, for example, fault traces used to model faults or fault wireframes used to create fault blocks in the Create Vein Surfaces command, a value is automatically added to a _USED_BY attribute. Again, this is automatically appended to the data objects used within the implicit modelling function. The following codes are used: