Many times your design files will be provided to you in 2D. The topography in these is illustrated through contour lines and other elevation information. Importing that file into Virtual Surveyor will not directly create a triangulated design surface that can be used for further analysis. Nevertheless it is possible to import that 2D plan and convert it into a design surface ready for advanced calculation in Virtual Surveyor.
This article will take you through a step by step guide to use 2D CAD file to generate design surface.
- Create a new terrain state.
- Drag and drop the 2D file in the projet view.
- Turn all layers off except project contours and elevation annotations.
- Set the Z value for each design item.
- Click on triangulate All (Method : 3D).
- Click on Modify terrain.
2D data import
Create a new terrain state and rename it with something like "Design" or "Project". Drag and drop the 2D plan within the project view. Virtual surveyor supports .dxf, .xml and .shp CAD file import. It's also possible to import point files as .csv or .txt.
Design items selection
2D plans usually contain a lot of information. You have to focus on design items that show the projected topography like contour lines, elevation points or any other elevation annotations. Click on those items and note their layers. In the project view, turn off all layers and then activate those specific layers only.
Hints : If relevant design items are mixed with non relevant items in the same layers. Create a new layer, select all the relevant items and move them to the new layer to easily isolate them.
Design Items elevation
As these are 2D, design items have to be edited to add an elevation. Select a polyline and in the TOOLS tab click on Edit Z. Select all (Ctrl + A) vertices and enter the elevation value in the box within the Edit group. Usually you find the elevation values as text annotations along the contours. Repeat this process for all the design items (you can edit points z values in the same way).
Design Surface creation
Once all the design items have been edited, deselect everything by pressing Esc. Go to Toposurface group in the HOME tab and make sure that Method is set on 3D. Click on Triangulate All to generate the design surface. Select this surface and in the TOOLS tab click on Modify Terrain.
Your Design Surface is now ready to be used as reference in Cut/Fill maps calculations.
Notes for 3D CAD files
If you get a 3D CAD file from the design office, the 3D TIN surface can be imported directly into Virtual Surveyor. Nevertheless, don't forget to modify the terrain according to that surface to generate a design surface ready for Virtual Surveyor.