Solids create sections
This function allows you to extract horizontal, vertical or inclined slices through an object (DTM / 3DM).
To run this function: Choose Solids > Solids tools > Create sections, or...
The plane of intersection of the slices is defined by entering the Y,X,Z coordinates at each end of a three dimensional axis line and by specifying the interval along that axis at which slices are to be taken. The first slice is taken at the start of the axis and then slices are taken at the specified intervals along the axis until the length of the axis is exceeded.
There are two results produced by the Slice Object function. The first result is a range of string files which contain the extracted sections in section coordinates. These files are saved to disk. The second result is a file which contains the extracted sections in real world coordinates. These sections are automatically displayed on the screen in a different layer. You may then activate this layer and save this file to disk.
The segments produced from the Slice Object function will have the same string number as the object number from which they were extracted. The segments produced may be open or closed segments. Closed objects will always produce closed segments when they are sliced. Open objects may produce open or closed segments when sliced. Closed objects are significant, because the slices generated from slicing a closed object can automatically be used for further processing where closed segments are required.
For each segment that is created as a closed segment, the direction of the segment will be clockwise if the solid from which it is being extracted is solid, anticlockwise if the solid from which it is being extracted is void and if the solid has no direction explicitly set then they will be made clockwise also. Solids which are not closed produce open segments sometimes and closed segments sometimes. The result is data dependent. In these cases, if the segment is closed then it is made clockwise and if the segment is open then it is left as it is.
One reason to slice a 3DM is to show one section at a time through a geological model along with the drill holes for that section posted to it. Each of these sections is represented by a single string file where the ID number of the string file created by the slicing function represents the section Northing, Easting or Elevation.
Define an axis line form
Section orientation
Perpendicular to axis
This option extracts the sections along the planes which are perpendicular to the axis.
Parallel to axis
This option extracts the sections along the planes which are parallel to the section line that has been defined using the mouse. To completely define the orientation of the section planes the dip, see below, of the section planes must also be defined. The position of each of the subsequent section planes is calculated by using the coordinates of the section end points, the section dip and the spacing between the sections.
Dip
This is the dip of the section plane. It is required to be defined when the section plane is parallel to the axis. It's value ranges from -90 to +90 with -90 or +90 being vertical and 0 being horizontal. The dip units are decimal degrees.
Digitise the axis
This button gives us an opportunity to digitise the axis in the graphics canvas using mouse.
Axis start
Enter the coordinates for the starting point of the axis line. The first slice is extracted at the axis starting point.
Axis end
Enter the coordinates for the ending point of the axis line. Slices are extracted either perpendicular or parallel to the axis line defined by the axis start and axis end points. Slices will not be extracted past the axis end point.
Choose Apply from the DEFINE AN AXIS LINE form to display the EXTRACT SLICES THROUGH OBJECTS form.
Extract slices through objects form
Layer name
Display only. The name of the active layer is displayed. The objects to be sliced must be in the active layer.
Define the objects to be sliced and the new layer name
Slice Layer
Enter a name for the layer which will be created to display the sections in real world coordinates. This layer name can be any combination of alphanumeric characters up to 32 characters in length.
Object Range
Enter the range of object numbers you wish to slice as a valid range identifier. Leaving this field blank causes all objects to be sliced.
Define the files to be created which contains the slices
Enter the Location of the file to be created and saved on disk which will contain the slices in section coordinates.
If you leave this field blank, the slices are drawn on the screen but are not saved to a file.
Section definition method
- Range specification
Select this radio button when the section range is required to be entered manually in the data entry field. - Interactive slider controls
Select this radio button when the section range is required to be specified interactively using the three sliders on the panel. The section's plane can be seen in the graphics canvas before actually extracting the sections along those planes based on the range specified using either of the two section definition methods. You can flip between the two section definition methods and the slice range will be modified to be consistent with the slider positions.
Define the slices required by a distance range
Enter the Range of slices to be extracted as a valid range identifier. A default range is supplied. The default specifies a range from the start axis point to the end axis point in one metre/foot intervals. One file is created for each ID number in the range.
Enter the Output file IDs of the string files to produce as a range specification. The number of items in the range should correspond to the number of slices to produce. If this field is left blank then the slices will be written to string files with IDs matching the slice offsets.
Select the section start, end and interval
Start distance
Use this slider control to set the section start position. The slider position value is displayed in the data entry field next to it. This data entry field also accepts direct input via keyboard and then the slider position is adjusted automatically.
End distance
Use this slider control to set the section end position. The slider position value is displayed in the data entry field next to it. This data entry field also accepts direct input via keyboard and then the slider position is adjusted automatically.
Section spacing
Use this slider control to set the section spacing. The slider position value is displayed in the data entry field next to it. This data entry field also accepts direct input via keyboard and then the slider position is adjusted automatically.
Messages
Slice found at aaa
Slice found at bbb
Slice found at ccc
No slice found at distance ddd
xxx points written to file yyyzzzzz.str
Result
The string files containing the slices in section coordinates is written to disk. The slices in real world coordinates are automatically displayed on the screen in the specified new layer. The message window confirms the processing.
Warning
No slices extracted from the model
No slices were found to extract. This could be due to:
- incorrectly specified axis points
- incorrectly specified object numbers
- no objects being in the active layer