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Feature editing

Object editing requires one or more objects to be selected in an Editable feature database (ensure the Editable icon is enabled in the Workspace Tree).

Enable the Edit mode button on the Feature Toolbar; all nodes/vertices on the selected objects will be displayed. Double clicking on a editable object will also enable the Edit mode for the object:

The following Editing functionality is available with the Select button enabled:

• Moving an object within the cursor plane – hold down the keyboard SHIFT

key whilst dragging the object to its new location. The object will be moved within the cursor plane. If more than one object is selected, all objects will be moved parallel to the plane of the last selected object (i.e. the object to which the cursor plane has snapped)

Offsetting an object with respect to its cursor plane – first hold down the

keyboard CTRL and SHIFT keys, then place the cursor over the selected object, ensuring that the cursor does not change to a directional cursor. Left click and drag the object to the new location. The object will be positioned and remain parallel to its initial orientation, i.e. it will be offset. If multiple objects are selected, they will be offset to the plane of the last selected object.

Deleting an object- with or without the Edit mode enabled, press the

keyboard Delete button to remove an object. Alternatively, right click on the object (not a node) and select the Delete option from the pop-up menu. Object Cut, Copy, Paste and Delete commands are also available from the

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Repositioning a node – placing the cursor over a node will change the

cursor to Move cursor. Click and drag the node to it’s new location within the cursor plane.

Add a node – placing the cursor over a polyline/polygon segment will

change to cursor to an Add Node cursor. Click to add a node at this location; this node can then be repositioned as above. Alternatively, right- click when the cursor is over the segment and choose Insert Node from the pop-up menu.

Delete a node – select a node by clicking on it (the cursor plane cross-hairs

will converge on the selected node) and press the keyboard Delete key. Alternatively, right click on the node and choose the Delete option form the pop-up menu.

Elastic movement of nodes – Moving a node whilst the Activate

Elasticity button is enabled will move its neighbouring nodes. The Radius of this options affect is set via the arrow button adjacent to the Elasticity button. This dialog also contains options controlling how the affected nodes are moved: this affect is represented graphically next to each option (Gaussian, Square, etc).

Note Feature Datasets can be exported using the Feature>Export menu option as a

number of formats, including dxf’s and ESRI shape files.

Exercise 12.3 Create a bifurcating solid

Encom Training\Training 3D\Geology

1. Import the Bifurication_Initial.dxf into a new feature database using the

Feature>Import menu option.

2. Generate a solid (no Body ID) and note the handling of the separation (bifurcation). Also note the polygon not utilized.

3. In order to handle bifurcating solids, intermediary shapes are required to guide the algorithm. Import the Bifurication_Final.dxf as a new feature database, and note the extra polygons guiding the separation of the body. 4. Generate a solid using the Bifurication_Final.fdb. Ensure that the Structure

Example Exercises 123

13 Example exercises

Exercise 13.1 Convert a series of drillhole fault intercepts into a 3D fault plane DXF.

Encom Training\Training 3D\Drilling\Project Files

1. Open the Copper Hill drillhole project into both 2D & 3D. A number of

drillholes contain a ‘Fault2’ intercept; In 3D, colour the drillholes so that only the Fault2 lithology is displayed:

- In the Drillholes Fields tab, having set the lithology field and

appropriate colour legend (created previously for this field), open the

Field Data Conditioning dialog.

- Use the Browse button to open the ‘Only_Fault2.edc’ file located in the

Project Files directory. This is a list of all lithological units in the Copper Hill project except the ‘Fault2” attribute; all units listed here will be converted to Null intercepts. Apply this null list.

We would like to create a fault plane encompassing these intercepts, but without manual digitization. Instead we will grid this data in 2D to create a grid surface

2. In 2D, desurvey the geology table (creating X, Y and X From and To

coordinates). Select out the Fault2 attributed intercepts, and save this as a new table called Fault2_points. Open this table.

3. We want to model our fault plane on the mid-point of these intercepts.

Create 3 new columns (eg X_mid, Y_mid and Z_mid) and populate these with the average of the appropriate From and To fields using Table>Update

Column, as below:

4. Make the Fault2_points table mappable using the new X_mid and Y_mid

columns (use AGD66 Zone55). These points now reflect the real world location of the fault intercepts.

5. Grid this table applying minimum curvature to the Z_mid field and a very

small cell size. Call the output table Fault2_grid.

6. This gridded fault plane can be viewed in 3D using Discover 3D>View

Surface in 3D. Note however that the fault surface extends above the DEM,

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DEM grid with the Grid Calculator, using the syntax pictured below. View this surface in 3D.

7. If desired, the depth and lateral extents of the Fault_new grid could be

clipped with a polygon using the Surfaces>Grid Utilities>Clip tool.

8. In order to build a fault dxf in 3D using the Solid Generator, we need a series

of polylines representing this surface. The easiest way to do this is to contour the grid. 25m spacings are recommended for this surface. Call the output Fault2_contours. Ensure that Contour Smoothing is enabled.

9. Import these contours into 3D as Feature objects. Within 3D, use the

Features>Import to browse for the Fault2_Contours.TAB file, saving it

either to the cosmetic layer or a new feature database. Ensure to Initialize the Z field from the ZValue.

10. Run the Solid Generator on this feature database to generate a fault plane

Movie Making 125

14 Movie Making

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