GM-SYS 3D Modelling

GM-SYS 3D is a gravity and magnetic modelling package that allows you to create surface-oriented 3D geological models that accurately represent subsurface variations and irregularities. It provides tools to build and refine models by comparing computed gravity and magnetic responses with observed data. Each model comprises multiple stacked surface grids, with density, susceptibility, and remanent magnetization distributions specified for the layer beneath each surface.

Calculations are performed in the wave number domain using Dr. Bill Pearson’s implementation of R. L. Parker’s 1972 algorithm. The program runs within Oasis montaj, giving you full access to familiar grid manipulation and display routines, along with specialized application-specific tools.

Working in Oasis montaj requires a project file (*.gpf). A project encompasses all items in your workspace, including:

  • Data files such as databases, grids, maps, voxels, geosurfaces, and 3D views

  • Visualization tools like histograms and scatter plots

  • Project settings, including the menus currently displayed

This structure ensures that your entire working environment is saved and easily restored.

To begin working with GM-SYS 3D, we recommend opening a new project and then loading the corresponding menus.

Open a New Project

  1. On the Project menu select New. The New Project dialog will open.

    You can also select Create new project from the startup dialog that appears when you launch Oasis montaj.

  2. In the New Project dialog, specify the name and location for your new project file (*.gpf), then click Save.

  3. The new project will open, enabling the main menus, toolbar icons, and the Project Explorer. These visual indicators confirm that the system is ready for use.

Load the Menus

  1. On the Project menu, select Manage Menus, or click the Manage Menus icon on the Project Explorer toolbar. The Manage Menus dialog will appear.

  2. Under Base Menus, expand the Interpretation node, select the GM-SYS 3D options, and click OK. The menus related to the modelling tools will now appear on the main menu bar.

The menu system is designed to provide quick access to a variety of tools and guide you through the primary interpretation and modelling workflows.

To automatically load these menus in future projects, specify them in the Default menus field of the General Settings dialog.

Accessing Help

Once the GM-SYS 3D menus are loaded, click the Help button in any dialog opened from these menu items:

  • The reference topic for the current dialog will be displayed.

  • Use the Help Topics tab to navigate to other topics of interest.

  • Use the Search tab to find specific topics by entering keywords.

*GM-SYS 3D topics are accessed through GM-SYS Modelling Help, separate from the Oasis montaj Help system.