Date: March 31, 2010
To:
Technical Exercise for FDOT ECSO Interview
FDOT Engineering Community
From: Vern Danforth, Application Support Specialist, Engineering CADD Services
Re:
CADD Driveway design help files provided with FDOT2010 software.
Background: With the implementation of the latest version of GEOPAK and the new Corridor
Modeler features, our office was tasked with creating help files to assist our users in the design
of urban type driveways on plan cross sections.
The 3 Methods discussed below each have the specific uses based on the level of design detail
that is desired for the plans.
1. Use the “model” driveway template component and selection set graphics from the
design file to target the driveway along template interval. These will semi-model the
driveway on the main template.
a. This is a tedious workflow because of all of the targeting, ranges and
troubleshooting when things are not working.
1. Target alignments must be imported for:
1. Drop curb gutter
2. Outer edge of first pad
3. Front and Back of sidewalk
4. Driveway tie to ground location(target)
2. The driveway slope can be entered from the design standards as a
parametric constraint for the component.
b. Although, it will slope the driveway to the surface at a defined target graphic
distance, it is up to the designer to define this distance.
c. It is the best scenario for when the main cross section interval happens
through a drive.
d. Does not apply when the driveway is skewed from perpendicular to centerline.
2. Use the “open” driveway template components and then add and edit the key stations
where the driveway centerline is located.
a. Good for one instance thru driveway.
b. Does not give an accurate model.
c. Easiest to use / apply.
d. Assists with the driveway design and tie slope determination.
e. Typically this is what is shown in the cross sections.
3. Create a 3d graphics to accurately model the proposed driveway;
a. Export a 3d file from the 2d display of the driveway.
b. Calculate the 18 elevations in a spreadsheet from the 2 eop tie points, assuming
driveway is on a vertical tangent, not curve. Figure 3a.
c. Using accudraw and modify element command in MicroStation to move the
vertices to the correct elevation, Z- Value.
d. Use GEOPAK DTM tools to extract 3d graphics to .dat, load and build a tin from
the dat file. Figure 3b.
e. Merge into the model and cut section as necessary..
Figure 3a
Figure 3b
This method when merged with the proposed roadway design model will most accurately model
what is to be built in construction.
It is the best for the following 3 scenarios:
a.) Provides most realistic presentation for rendering images of the proposed
design
b.) Best for animations of the project
c.) Most accurate model for Automated Machine Control file.