Preparation of Government Furnished Information from Model
Projects with earthwork, grading, and staking require 3D design data provided for contracting purposes and for WFL project personnel.
Purpose: Provide instructions to produce the following design data;
- Convert horizontal alignment and profile grade data to LandXML format
- Convert and validate TIN file to LandXML format
- Create 3D break line drawing in DGN format
- Best practices for digital files
Convert horizontal alignment and profile grade data to LandXML format
To begin open the HA dgn file in the working directory containing the project gpk file. Next check out gpk file. Next, Open the Coordinate Geometry menu. To start go to Applications > GEOPAK > Road > Geometry > Coordinate Geometry. Or use the COGO icon on the Classic Geometry task menu.
Next, select the gpk file (Job) using spyglass and enter the users initials in the Operator Code field.
If the the Project manager is being used, this step will be skipped automatically.
The Coordinate Geometry menu (COGO) will appear. To export the horizontal alignment (chain) and profile grade, go to File > Export > LandXML 1.2 Geometry.
The Export LandXML menu appears. Fill out all fields on the menu according to below:
Project Name: Use P6 project name.
Description: Use description for the chain and profile exported.
LandXML File: Use the spyglass to create a file in ProjectWise using No Wizard. This creates a path and link for proper export.
Output Mode: select Create.
English Units: International Feet or US Survey Feet. Select the units that correspond to design units.
Element Type: select Chains.
Export All Chains: generally do not check box. Since gpk files usually contain many chains, only export the necessary project chains such as center line alignments, approach roads, and wall alignments.
Chain: select from pull down the chain to be exported.
Export Profile(s): generally check box. Select corresponding profiles that are associated (stationed) with the chain to be exported. Hold shift key to select multiple profiles.
After all fields have been carefully filled out. select Export
An Alert menu will appear, this is standard and is writing to the linked file created earlier. Select Yes.
Close the Export LandXML 1.2 menu after operation.
To continue exporting other chains and profiles, it is best to check in the newly created Land XML file. When checking in the LandXML (.xml) in ProjectWise, there will be warning return. Make sure export menu is closed and then select continue.
To export more chains and profiles. Re invoke the File > Export > LandXML 1.2 Geometry command on the COGO menu. For best results, first clear LandXML File field, then press tab, and then select spyglass to create file and path for a new file.
Open the created LandXMl (xml) files with UltraEdit and the file should look similar to this image. Study the file. The chain data and profile data, at the end of file, will look familiar compared to the GEOPAK chain and profile description. Note the GEOPAK chain name is contained in the XML file and is highlighted below.
Convert and validate TIN file to LandXML format
Currently Corridor Modeling/Roadway Designer produces two engineered 3D models of the design surface. The two models are produces as the DTM and TIN files. The TIN file represents a surface only. This surface file can be used in construction operations but must be converted to a LandXML file in order to be universally used by other software and hardware. Roadway Designer has the ability to create "Alternative" surfaces identified within templates. Alternative surfaces will be created at the same time the (top) designed surface is created. The TIN export and check process is the same for all TIN's produced by Roadway Designer.
Export TIN to LandXMLTo export TIN file to LandXML, go to the DTM tools on the Civil Workflow task menu, Then select Export LandXML icon.
The DTM Export LandXML menu will appear. Load the design TIN file using the spyglass and fill out Project Name and Description.
Next, Select the proper English Unit. Be sure to confirm working units.
Next select LandXML File: Create a destination file. For best results, first clear LandXML File field, then press tab, and then select spyglass to create file and path for a new file.
Create LandXML File. Use naming convention prefix and good descriptors. Next select Save.
The DTM Export LandXML menu will reappear after the destination file has been created. Now select Export.
Select OK. This is overwriting the file created earlier.
Afterwards, Close the DTM Export LandXML menu.
Validate LandXML file
Since the exported LandXML file cannot be visually inspected to validate a proper export, it is necessary to import a TIN from the LandXML for comparison.
To start the validation process, go to the DTM tools, then select Import LandXML icon.
The DTM Import LandXML 1.2 menu appears. Load the LandXML (XML) file and fill out DAT/TIN Prefix field for the comparison TIN file. Then select Import. The DAT/TIN Prefix is a prefix added to a new file in order to keep track of newly imported file. For instance the example below will create two files named Check-mf07901_A1-001.dat and Check-mf07901_A1-001.tin. The imported TIN file will be validated in the next steps.
Compare TIN's to validate the LandXML file
Next in the validation process is to visualize and compare the TIN created from importing the LandXML to original design TIN, this will validate the LandXML was a proper export.
Visualize TIN. The first step in validation is to visualize the TIN imported from the LandXML.
Go to the DTM tools, then select Load DTM Features icon.
On the Load DTM Features Menu, first select File > Open
The Open Preference File menu appears. Navigate to; \Documents\PW_ Resources\Bentley\GEOPAK\Bin\. There are four (4) configured preference files to choose from. For this exercise select WFL_DTM_Features_Alternate.lpf. The contours visualized will be deleted after the validation exercise.
After opening the preference file, most of the settings are configured except the following:
- Use the spy glass to select the TIN file imported from LandXML;
- Select Contours leaf then;
- Select the Read button. This will load the data from the TIN file;
- In the Range area, manually round the Minimum Z: value DOWN to a whole unit;
- Round the Maximum Z: value UP to a whole unit;
- Then select Load.
A visualized TIN should appear. Inspect for any obvious errors and abnormalities.
The method below uses a volume calculation method to compare surfaces. If two surfaces are identical then there should be no difference in volumes. In the convert, export, and import process there is sure to be algorithmic differences along the process producing minute differences, so a reading of zero (0) should not be attainable. The check process is to assure there was a complete and proper LandXML file produced and it is representative of the design TIN.
Next step is to compare TINs. Go to the DTM tools, select Volumes.
In the Volume Calculations menu, Load the two TIN file for calculation comparison. The comparison is between a TIN file created from the LandXML file and the design TIN file that was the source of the LandXML. An Optional ASCII output file can be created for documenting. Then, select Process.
The volume calculations are displayed after processing.
The Cut and Fill Volumes should be very small. What is this data conveying? The cut volume value should be interpreted that throughout the entire surface there are differences in areas that are calculated to be 16.72 cubic yards in total and is where the Imported TIN falls below the Designed TIN. The converse would be true for the Fill Volumes. The Balance is the Cut Volume minus (-) Fill Volume. A delta of 2.6 cubic yards in 36 acres is 0.07 CY/acre or is less than 2 cubic feet per acre. A very small difference and would be considered a valid exported LandXML file.
Another method of validation would be to compare the overall Cut and Fill volumes in the project. The project total volume results can be obtained from the Earthwork input file OR comparing the subgrade surface (TIN) to the original ground surface (TIN). Below is a capture of these two TINs being compared using the Volumes Calculation tool.
On this project there is more excavation than embankment and the pay item is base in excavation so an error calculations will be based on excavation (cut) value. The project plan quantity is 127,172.0 CY and represents the total amount of cut to reach the designed subgrade. Next, the difference in cut volumes of the the two final TIN's was 16.72 CY. The percentage of this quantity compared to the over all cut for this project is very small. 16.72/127,172 = 0.00013 OR 0.13%. This falls well within any project allowances and any measurable quantities.
Create 3D break line drawing in DGN format
Roadway Designer is also capable of visualizing the 3D engineered model a 2D or 3D DGN. It is helpful to visualize the model during the design process to check design intent and quality control. Other software can make use of drawing containing the 3D break lines for construction operations.
Once the design has been finalized, a final DTM and TIN are created and used to create cross sections that are in turn used in earthwork volume calculations and construction note reporting. A final 3D break line drawing must be created during the model creation operations.
First create a 3D DGN file using standard FLH seed file.
Next, in the 3D DGN, open the Corridor Modeling menu and then load the project (.rdp).
Next, open Roadway Designer menu, and then open the project corridor (.ird). Check project setting before creating surfaces. Next, select the Create Surfaces icon.
The Create Surface menu appears. Use the naming convention prefix when creating the surface files and use the setting below. The Display in Plan View: Features is the setting that draws the 3D break lines. Then select Apply.
Once the surface creation process is complete close the Create Surface menu.
Zoom to fit view then navigate and rotate the view for a closer view of the 3D break lines. The break lines are formed from each point in a template. Be sure only the 3D break lines are in the drawing model and the DGN file.
Best practices for digital files
Use of best practices to ensure design data is organized and will be included in the procurement process.
Best practices include:
- Naming conventions
- Storage locations
- Transmittal information using the WFLHD-2, PS&E Assembly and Review form
Use the project prefix and the chain name as the name string for LandXML file names. Alternatively the project prefix and a road name would make a good LandXML file name as well.
A sample of a naming scenario:
Project Name: Jojo Creek Road 79(1) Reconstruction
Project Number: MT PFH 79(1)
WFLHD File Name Prefix: mf07901
In the above case the designer generated several chains and used a chain name convention such as RD79_A1, ...A2, A3, etc. Profile names should reflect the chain name such as Pro_RD79_A1. Other chains used in the project were RD201_A1, RD_2561 and WALL_RT_1356. As a reminder it is a best practice to maintain good descriptive chain names in GEOPAK that are 14 characters and less, contain no spaces, contain no special characters, and use only underscores.
Given above, appropriate LandXML file names would be:
mf07901_RD79_A1.xml for the project alignment,
mf07901_RD201_A1.xml and mf07001_RD2561.xml for the approach roads, and
mf07901_WALL_RT_1356.xml for the wall alignment.
Keep in mind that the profile is exported to the LandXML file along with the chain and caries the GEOPAK profile name into the file as shown in partial example LandXML file below.
All files to be provided to acquisitions should be stored in the following location; pw:\Documents\state\corridor\project number\Acquisitions\PS and E\Physical Data\.
Coordinate with acquisitions and the Contracts Liaison Engineer (PS&E signoff) when providing reports, listings and digital files.
Use the WFLHD-2, PS&E Assembly and Review form to provide a listing of files being provided as Government furnished information. In the Design Data listing area best practice is to provide a listing of each file name, the file format, file contents and description:
mf07901_RD79_A1.xml - LandXML file format - RD79_A1 Chain and PRO_RD79_A1 profile, Primary design alignment chain and profile.
mf07901_RD79_A1_BlueTops.csv - CSV file format - RD79_A1 Blue Tops in XYZ style