Corridor Processing - Improving Performance

Product(s):OpenRoads Designer, OpenRail Designer
Area: Corridors



When working with corridors in OpenRoads Designer, there are many options and settings that can help optimize the processing speed of the corridor.  Here are some helpful tips: 

Utilize Different Corridor Feature Definitions for Different Stages of the Product

During the various design stages of the project, to optimize speed and performance, you can create and use different Feature Definitions with settings that produce a increasingly more detailed model:

Below is a list of the settings in the Corridor Feature Definition that increase/decrease the level of detail in the 3D model:

- Template Drop Interval Multiplier (decreases number of template drops)
- Horizontal Cardinal Points (increases number of template drops) 
- Vertical Cardinal Points (increases number of template drops) 
- External Control Points (increases number of template drops) 
- Densify Horizontal (increases number of template drops) 
- Densify Vertical (increases number of template drops) 
- Enable Clipping (adds additional post processing computations in 3D model)
- Top Mesh Display (adds additional 3D elements)
- Bottom Mesh Display (adds additional 3D elements)
- Components Display (adds additional 3D elements)
- Major/Minor Contour Display (adds additional 3D elements)


Do Not Set Unnecessarily Small Template Drop Intervals

Careful consideration should be given when determining the drop interval used for a corridor. Generally, this value is equal to or less than (but still a multiple) of the desired interval for the final cross sections. For example, if the final deliverable is 25 foot cross sections, then set the template drop interval to 25'.  

Keep in mind that smaller drop intervals will result in longer processing times. Also, it is not necessary to set the interval so small that it encompasses all desired cross section stations.  Instead, these stations can be processed using critical template drops that will be added when the corridor processes (cardinal points, external control points, horizontal and vertical curve densification).

Additionally, if you are working on a small station range (i.e., an intersection), you could consider temporarily changing the template drops in other station ranges to a very large number (i.e., 1000). This would essentially disable corridor processing outside of your current area of concentration.

Avoid Point controls that use “Profile from surface” reference elements

If the reference elements for point controls are elements that have been draped to the surface, those reference elements will contain a very large number of vertical PIs. Trying to process all these vertical PIs with external controls set to “True” in the Design Stage Settings will negatively impact processing times.

Consider instead letting the template do the work of matching the existing ground elevations. Using a Project to Surface constraint on the template point will eliminate the need for a vertical point control with a vertex at every break in the terrain, and may eliminate the need for a point control altogether.

Deactivate corridor Processing to increase performance

There will be many times during design when it is not desirable to have the corridor reprocess every time an edit is made. For example, if creating numerous point controls, it is more efficient to have the corridor reprocess after adding all points controls as opposed to reprocessing after adding each individual point control. To achieve this, locate the corridor in Project Explorer > Civil Model. Right-click on the corridor name and select Lock – Deactivate Rule to lock the corridor.

With the Corridor locked, it will not automatically reprocess. Use the Process Corridor tool to reprocess the corridor and apply the edits.


You can now make edits to the corridor without the corridor processing after every change. Once editing is complete, simply follow the process above to unlock the corridor.


Use an active terrain model only as large as necessary

For optimal performance, it is recommended that the active terrain model be only as large as is necessary for the project. If you have a 10 mile long existing topo terrain model, but your project is only 2 miles, use the Create Clipped Terrain Model tool to remove portions of the terrain model that are not necessary for the project.


Additionally, consider using Clear Active Terrain Model to disable end condition processing. If you are working on an area of the project that does not involve end conditions, this will help to speed up processing times.

Limit the amount of clipping occurring along your Corridor

Clipping the 3D model is a processor intensive process.  If possible, attempt to remove components/side slopes using template drops or End Condition Exceptions, instead of Clipping References.  For example, if you are planning to clip the area behind the back of curb at an intersection, test to see if this can be done with template drops (that do not contain the back of curb components and slopes) or by adding an End Condition Exception that places the "Backbone Only" at a specific station range.

Adding additional clipping references along a corridor compounds the processing time.

Consider using Point Controls instead of the Horizontal Feature Constraint

If you want a point to follow a specific feature, consider assigning a Point Control to that point for the desired station range, instead of simply using a Horizontal Feature Constraint.  This decreases the processing time because, for point controls, the corridor only has to find one feature, however for Horizontal Feature Constraints, the corridor has to scan the entire DGN for matching features, then do a calculation to find which one is in range.

The benefit of not having to know the start and stop stations for Horizontal Feature Constraints may outweigh the increased processing time, but it is worth considering.

Other Considerations:  Detach raster images while running civil design processes

When working with designing your civil model, raster images are not necessary and they utilize a lot of memory. Detach any raster images to make sure to free as much space as possible and attach only when civil design is complete.

Additional Resources

Also see the following article regarding increasing the value of ms_memory_freelimit.  There isn't much information/detail other than the fact that it is a Windows OS user variable:

Also see this article regarding a "Lock Pages in Memory" privilege that requires the user access control be disabled or that MicroStation be run with administrator privilege:


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