Tech Tips

Increasing the speed when using Large Data Sets

This Tech Tip will explain various was to speed up Civil Designer when using large data sets.


Display Generated Contours instead of Quick Contours

Despite the name, quick contours is slower than generated contours, quick contours are calculated as you work, i.e. they are live, generated contours read the contour details from a contour file and therefore the redraw speed is faster. If you use generated contours remember any changes made to the dtm will not be shown in the contours unless you re-generate them.

To create Generated Contours, Terrain Mode Terrain Menu Generate Contours

Once the contours have been generated, the Generated Contours may be switched on in the display settings.

Remove Duplicates/Automatic Screen

Deleting unnecessary points from the dtm will increase redraw speeds, there are 2 methods to do this:

Remove Duplicates:

This function will remove duplicated points from all or selected surfaces. Duplicate points are defined as points where the horizontal and vertical ordinates are identical to other points in the model. Depending on selections made in this function, heights can also be selected as a factor when determining whether a point is duplicated or not.

This function is faster to process than the Automatic and Manual Screen functions as no searching for points in other blocks is required, only points within an index block are scanned to detect duplicates..

Survey Mode: Editing Menu Remove Duplicates

The Output Manager dialog will appear (if the Output manager has not been disabled), make your selections and

Use height in comparison Check this option in order to remove points which are duplicated in horizontal, vertical AND height ordinates as opposed to the standard of horizontal and vertical ordinates only.
Retain line information Check this option to transfer the line information from deleted points to points being retained.
Use filter Check this option in order to apply a point filter by name and/or surface.
Use fence Check this option and select a predefined fenced area in which to limit the calculation.

Automatic Screen:

This function is used for rapidly eliminating duplicated data or any points that fall within a certain radius of each other.

Points that are on top of one another, or even very close together, can present severe problems in forming terrain models. This is particularly true if their Z values differ and they should be eliminated whenever possible.

After setting the screen details you will be shown a point filter dialog. The program will make its own selection as to which points will be removed and therefore the careful selection of a name filter is critical. Points with no names will be first choice for deletion, followed by lower case descriptors and, finally, points with upper case letters and numbers (like NRB142) will be the least likely candidates for removal.

Rescale Survey:

This function re-scales the current Terrain database and resets the data structure.

You are prompted with the calculated centre point coordinates and site diameter, which may be changed. A constant may also be added or multiplied to the points at the same time.

If the block structure of the database becomes unbalanced (typically as a result of adding large amounts of data outside the original site limits) efficiency can degrade. This routine actually resets the block structure by performing an automatic ASCII export and re-import

Switching off Proxy Graphics:

File Menu Option Settings

Under General, switch off "Save proxy graphics"

When saving a drawing in Civil Designer, you can opt to save Proxy Graphics. The proxy graphics store a visual representation of each Civil Designer entity, which enables you to view the DTM, Roads, Sewer, Storm or Water pipes when you open the drawing in AllyCAD.

Civil Designer entities (Roads, Pipes and DTM) will be loaded as Proxy Entities in AllyCAD. You will be able to view the proxy graphics of these entities, but you will not be able to edit them.

Switch off the Interactive Roads Expert:

If working in Roads Mode, and you are working on very long roads, the Interactive Roads Expert (which is on by default), can slow down the system performance while you are designing/editing your road.

To disable the wizard, Roads Mode, File Menu Option Settings

Switch off the smoothing of roads lines:

Smoothing the road display lines on long roads will also slow down performance.

To switch off the smoothing, Roads Mode, Settings Menu Display Settings

Make sure to select No under the Smth column.

General Considerations:
  1. Make sure you have all the latest Windows and Civil Designer updates installed.
  2. When running large projects makes sure you have no unnecessary programs running in the back ground.
  3. Make sure the computer you are using is at least the minimum recommended specs:
Core 2 Duo processor (2GHz)


SXGA (1280x1024) display

240MB free hard

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