- Frans Basson
GEM4D Version 184.108.40.206 available for download
Updated: Dec 15, 2019
The main addition to GEM4D Version 220.127.116.11 is the ability to retain data changes made to filtered data sets; as this ability enables the assignment of a default value, with subsequent changes to filtered extractions. A geotechnical or risk model can thus be easily created from a grid of data points as indicated in Discussion - Building geotechnical/risk models.
Seems everyone now transitioned to the 64-bit version of GEM4D, and the 32-bit download was removed. Let me know if you are still using a 32-bit computer and I can make a download available.
Data added or changed during filtering operations are now retained in the master data set. This is a huge improvement that allows for the quick construction of geotechnical or risk models - see Discussion: Building geotechnical/risk models.
A pick tolerance mode was added for the easy picking of points and lines under "Ribbon> Settings => Mouse interaction => Picking": "Fine" is the default setting that works well for most cases. "Coarse" is more forgiving for the picking of points and lines.
A toggle option was added to "Top toolbar => Toolbox 1 => Single Delaunay object". The default is a checked state, where all visible meshes are combined before draping of a surface. If the toggle is unchecked, an separate surface is draped to each individual object.
Ability to delete columns in a data grid by mouse right clicking and select "Delete selected columns" from the context menu.
Calculate volumes between surfaces with "Top toolbar => Toolbox 1 => Vertical volume between meshes" - thanks JV.
Ability to delete columns in data grids by mouse right clicking and selecting "Delete selected columns" from the context menu.
Ability to remove points and lines from all files by selecting all relevant objects in the lower list-box, mouse right click, and select "Delete all points and lines" from the context menu - thanks JP.
Support for the Imperial System was added to PrisVec - thanks TB.
Hide the "id" columns in data grids (as this column confused users) and brought back the "Reset grid row sorting" option in the context menu to reset data to their original order.
The "Custom menu" options for the colouring of objects were grayed out as not yet ready.
Changes to the data grid context menu layouts to make them uniform and more logical.
Various large data optimisations to the data grids.
Data selections were lost in data-grids when right-clicking with the mouse to activate the context menus - fixed.
"SHIFT" did not work on the data grid context menu option "Pick coords from scene" - fixed.
Discussion: Building a simple geotechnical/risk model
Geotechnical and risk models can be built in various ways, and one of these options will be discussed below.
Step 1: Build a regular grid of points surrounding the area of interest
Load the meshes that define the area of interest with "Ribbon => Mesh => Load and import different file formats => Load/Add DXF".
Create a regular grid on the preferred spacing with "Top toolbar => Toolbox 2 => Create grid in mesh bounding box". Make sure to add values to "Extend the data bounds" that is equal to the distance from the meshes that is of interest in all three directions (typically around 20).
The original meshes will automatically be hidden, and the created regular grid shown.
Convert the created regular DXF-grid object to a CSV data-file with "Ribbon => Mesh => Export files => Mesh info as CSV => Poly, line and point vertices". This export all visible vertice data to a CSV-file.
Delete the created regular grid DXF mesh object by right clicking on the name in the upper list box, and select "Remove selected files".
Load the save regular grid CSV-file with "Ribbon => Markers => Load files => Text (CSV)".
Make the original meshes visible again with the check-boxes to the left of the objects in the lower list-box.
Step 2: Filter out the points far away from the meshes
Subdivide the original meshes into smaller polygons "Top toolbar => Toolbox 1 => Subdivide lines/polys - split to size", which is required for two reasons: 1) Next step works best if the mesh vertices are reasonably close together. 2) A sub-divided mesh is required when colouring meshes on scalar values, as the meshes are coloured on the vertices. 3) Select a value that is significantly smaller than the value in the next point (typical value around 10). Select a reasonably value though, otherwise the file will become very large.
The data can be kept in as a rectangular block of values, although that creates a very large data set. Normally the data close to the meshes are filtered out as follows: 1) Select "Ribbon => Marker => Marker actions => Distance => Add grid distance column", which add a column with the distance the closest mesh vertice. 2) Move the mouse to the created column heading, and mouse left-click the downwards arrow (that becomes visible when the mouse is hovering over the heading). For large data-sets, this could take a while and suppress the urge to press the arrow multiple times. 3) Select "Numeric filter" down the bottom, then "is Less than" and type a distance (typical value around 20) and press "Enter" on the keyboard. Only the data closer than the selected value from mesh vertices will remain, the others will be filtered out.
Save the filtered data-set by right clicking in the data-grid and select "Save data as CSV-file" from the context menu.
Load the save CSV-file with "Ribbon => Markers => Load files => Text (CSV)", which will replace the existing file.
Step 3: Add relevant values to columns
A new column or columns can be added to the data by right-clicking in the data grid and select "Add blank grid columns". Columns can only be added when all the loaded data is shown, and the option is not shown when data is filtered. The default value in the created column will be "0".
Change the value to any number by: 1) Left clicking in a cell of the column. 2) Type the appropriate value and press "Enter" on the keyboard. 3) Right click on the cell with the new value, and select "Copy to visible column cells" from the context menu. This action will copy the selected value to all visible cells in the column.
Filter data in the data-grid as explained in Step 2, on in the scene with the vast array of options under "Ribbon => Marker => Marker filters => Manual". The "Relative to meshes" option is especially powerful to select data within, outside, close-by, above, below etc. meshes.
Change the values in the filtered data to their appropriate values as explained two points up. This can be done as many times required, as the filtering is cumulative and different filters can thus be added and values assigned.
Reset the filters with "Ribbon => Marker => Marker filters => Reset manual" or "Ribbon => Marker => Marker filters => Reset all". The values that were changed during the filtering is retained in the resulting data-set.