The Complete Knuckleheads Guide to using GEOPAK

GENERATE THE PROPOSED 3D MODEL (the NEW more accurate method)

FIRST OF ALL YOU MUST HAVE THE FOLLOWING:

A .DGN file containing your existing ground and proposed elements, ie. top of pavement, ditch, cut and fill slopes etc...
A .DGN file that contains your construction limits and horizontal alignment .
A blank 3D .DGN file for displaying your 3D model.

Copy one of the 3D files listed below from the F:\Resource\Seed directory to your working directory (name it whatever you want) and get into it.

Metric_3D.dgn (metric 3D file)
English_3D.dgn (english 3D file)

Open the 3D model file and...
APPLICATIONS > GEOPAK ROAD > 3D TOOLS > 3D Modeling

This brings up the "3D Modeling Tools" dialog box. Click on User and set the 3D Model Preferences as shown. The Min rule spacing is the interpolation grid density, ie. a spacing of 1 is much finer than a spacing of 5. Key in the Job number and chain.

Press 3D Alignment...as you may have guessed, this brings up the "3D Alignments" dialog box.
Key in the chain and profile or use the selector buttons.
Key in the desired scales and plot parameters...press APPLY

Execute the MicroStation command FIT VIEW. Your alignment should now be displayed.

The next option available (back at the "3D Modeling Tools" dialog box) is SUPERELEV SURFACES. The dialog box is shown below. This option takes awhile and unless you need an absolutely perfect 3D model... I would skip this and go on to 3D CROSS SECTIONS.

Press 3D CROSS SECTIONS...

Press File and select the file that contains your cross sections.
Either key in the station range desired or go with the default station range, which should be your whole cross section file.
Key in the appropriate levels that comply with your existing ground and finished grade cross section elements. BE VERY CAREFUL HERE! As the saying goes, "garbage in...garbage out." You might want to open your cross section file and verify your cross section element criteria. When you've finished verifying and keying in the Existing Ground Line and Proposed Finish Grade fields, press APPLY.

When APPLY is pressed, GEOPAK accesses your cross section file, grabs each cross section and throws them into your 3D file as 3D cross sections. This is the basis for actually creating the 3D model. Next...

IMPORTANT!!! ATTACH THE 2D FILE THAT CONTAINS YOUR HORIZONTAL ALIGNMENT TO THIS 3D FILE ... AS A REFERENCE FILE. In most cases the only levels that you should have turned on are the ones that display the actual alignment and the construction limits.

Press INTERP BETWEEN XS...this brings up the "Interpolation Between XS" dialog box. This is the process that creates a wireframe model.

If your horizontal alignment file is, in fact, a 2D file...toggle the "Method" button to Longitudinal. If for some reason you've opted to use a 3D file for your horizontal alignment...you would toggle this to Surfaces.

The next step is to select the station range between the 3D cross sections for creating the wireframe model. This routine is really sensitive and I would recommend doing short sections at a time, unless you have really simple cross sections. Geopak tells me that this routine actually works faster if you do small sections at a time rather than doing the whole project at once. Anyway, to select the station range to be processed...

Press the first DP for the beginning station and snap to the far left most offset of the first cross section to be processed and accept it.
Press the second DP for the beginning station and snap to the far right most offset of the first cross section to be processed and accept it.
Repeat this procedure for the ending station.
For now...leave the bottom two toggles toggled off. When the dialog box is completed, press DRAW SURFACES.

As mentioned earlier...this routine is very sensitive and if you have problems with this portion come see me or read this chapter in the manual. It's explained in detail in "Pavement Definitions, Cross Sections & Earthwork", Part III, Chapter 1 in the Geopak 2001 Manuals.

When this process is complete...you're ready for actually viewing your 3D model using the Geopak tool, DRIVE THROUGH. See Drive Through.

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