Creating subgrade surfaces
Click in the CrossSection window, and navigate to CrossSection > Surface > Add.
A dialog box will appear.
Type a material name, and select the surface type Subgrade radio button.
![](https://mytopcon.topconpositioning.com/sites/default/files/styles/totalcare_article_side_image/public/totalcare_article/content_images/creating_subgrade_surfaces.png?itok=PnCuajrF)
Navigate to CrossSection > Surface > Sequence to open the dialog box as shown.
The surfaces should always be entered from the top down sequentially, that is, below the design surface.
![](https://mytopcon.topconpositioning.com/sites/default/files/styles/totalcare_article_side_image/public/totalcare_article/content_images/subgrade_sequence_0.png?itok=rD_6bgV2)
Assigning surface thicknesses
Navigate to Design > Subgrade Selection > Pavement Parameters.
In this dialog box, define the surface from the top down with a start station, thickness (project units), and the extent across the template that you want them to run, such as LEP REP.
Repeat for each surface.
![](https://mytopcon.topconpositioning.com/sites/default/files/styles/totalcare_article_full_image/public/totalcare_article/content_images/pavement_parameters_0.png?itok=rBCaXuYo)
Creating subgrade surfaces
Navigate to Design > Compute Design.
The subgrade surfaces will now be generated.
They can be edited by selecting on the active surface as highlighted in the image and changing the surface color. Note: The Property toolbar must be enabled.
The design is now ready to be transferred to the survey view.
![](https://mytopcon.topconpositioning.com/sites/default/files/styles/totalcare_article_full_image/public/totalcare_article/content_images/subgrade_surfaces_compute_design_0.png?itok=c6FcRW55)