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Model Names

Plan Preparation Models

(Models appear in approx. order of creation)


Model containing a field surveyed traverse string PSSA. Traverses may be received as separate dump files (eg. RAxxxxx.SDR, RBxxxxx.SDR, etc. - where xxxxx is the project number). Individual traverses are typically combined to create a single traverse in this model. The Survey Section is responsible for closing/adjusting traverses.


Model containing existing project detail/topo strings as recorded in the field by survey data collectors. This model is created by editing then merging individual topo dump files (eg.TAxxxxx.SDR, TBxxxxx.SDR, etc. - xxxxx is the project number).


Model containing existing aerial survey detail obtained from an outside agency.


A model containing one or more boundary strings (BDRY, BY01, etc.) Boundary strings may be used in merging models or controlling creation and trimming of the triangle string (although PBRK strings have generally superseded boundary string needs in triangulation).


Model containing the triangulation string (TRIA) created by using select topo detail string information. Triangulation interrelates points on and between strings, creating a surface from which elevations can be extracted at any location.


Model containing the existing ground contour strings (0 [zero] = major, D = minor) created by surfacing (contouring) the TRIANGLES model.


Model containing reference master alignments (MCxS) created using center of road shots (CO) to establish tangents and adding approximate curves (to nearest 15'). Reference alignments are used to cut profiles and cross sections which assist in verifying the accuracy of the TOPO & CONTOURS models via a field check. Existing ground elevations are attached to the master strings by sectioning them over the TRIANGLES model. Strings in this model must be refined (drive points added, etc.) if they are to be used for design purposes.


Model containing existing ground cross sections cut referencing the master string MCxS in PPALIGN. Existing ground sections are cut over the TRIANGLES model at each point along the master string and assigned string labels beginning with 'E'. Separate section models are maintained for each unique master string.

Note: These models are record files! No modifications are to be made without the prior approval of plan prep.

Preliminary Design Models


Model for storing Legacy Alignments. Legacy alignments are used by the Bureaus of Highway Design, Maintenance and Right-of-Way to determine where the existing roadway and structures are located, to better define our ROW assets.


Model for storing all master 'MC' and geometry 'GC' strings with proposed elevations, as well as the corresponding existing ground 'LZ' strings. During early stages of a project, a large number of alignments may be created. Side road alignments are sometimes stored in a model named after the road (ex: MAPLEST).

Note: Master 'MC' and the associated existing ground 'OC' strings must reside in the same model to be drawn up or plotted together on a profile.


This model contains the master string 'MCxx' with proposed elevations (copied from PALIGN), and the associated template (created with DESIGN options) and Earthworks (INTERFACe options) strings. Separate design models are maintained for each master string.


Model for storing all driveway alignments.


Model to contain the proposed preliminary design contours.


Model containing all cross sections for master string MCxx. Section Sets are listed in Cross Section Set Labels. Separate cross section models are maintained for each master string.

For the most accurate results, existing cross sections 'E' should be cut over the TRIANGLES model.


Model intended to store sight lines and visibility envelope strings resulting from Visibility Analysis. Separate sight line models are maintained for each master string.

Note: These models are intended for preliminary use only and are technically considered 'record' files. No modifications are to be made without the approval of the preliminary design engineer.

Final Design Models

When a project is turned over, the preliminary design engineer shall provide the team with a list of the models and pertinent strings in each. The final team will copy the pertinent strings into the appropriate Final Design models where work will progress. Final work should not be done on Preliminary Design models.

Model descriptions are identical to Preliminary Design models with the exception that they are for Final Design use.


Model containing the final triangulation string (TRIP) based on the proposed design template and interface strings contained in the FDESIGN MCxx model. A PBRK or boundary string may be created to prevent contours from being generated outside the limits of the interface (slope) lines. These string(s) would be stored in the appropriate FDESIGN MCxx model.


Model to contain the final contours generated by surfacing the FTRIANGLES model.

Note: These are the most commonly encountered models on a project. When creating additional models, use names that easily and accurately reflect the information contained in the model.

Other Models


A temporary model used to store alignments transferred from MicroStation to MX. For more details, see Transferring MicroStation Alignments to MX.


Survey detail points as feature strings to be used for developing cross sections. For more information, see Adding Details to Cross Sections.

New Hampshire Department of Transportation
PO Box 483  |  7 Hazen Drive  |  
Concord, NH  |  03302-0483
Tel: 603.271.3734  |  Fax: 603.271.3914