In this lesson I will deal with the modeling of the elements found in the inner courtyard. To start I will create a Layer called 3D-Terrain. After that, I just need to activate it and possibly choose another color. To that end, I’m going to click on this square and select a dark green shade from the palette.

Considering that the yard is completely flat, I will try my best to model its surface as simply as possible. To begin with, I’ll draw one closed poly line, making sure it covers the entire yard. It won’t be difficult for me because there are enough elements on the model that I can use to precisely position the characteristic points. I will create the last segment with the help of the Close option because it is a guarantee that I will get a completely closed contour.

Since I need a flat surface for the yard, I will start the Plansurf function and select this contour with the Object option. If I press Enter after that, a new element will appear on the screen that pretty much matches what I wanted to achieve. In order for everything to be just as it should be, I will try to raise the middle of the yard a little and in that way ensure normal drainage of rainwater.

To achieve this, I need to select the 3D Modeling option from this menu and go to the section called Surface. After that, it won’t be difficult for me to run the Convert to NURBS function and select the surface that is in the middle of the object. If I then press Enter, AutoCAD will convert the selected element into a so-called Not a Uniform Rationally Based Spline (NURBS for short) which is really just a different way to represent a single spatial surface. In order to really be able to change some of its characteristics, it is necessary to start the Show CV function and thus display the so-called control vertex (Control Vertex). After that, small blue dots will appear in the corners, which unfortunately are not very helpful, because I need something in the middle. To finally achieve my goal, I still need to apply the Rebuild function and select the area that represents the yard. After that, a new frame will appear on the screen, so it will not be difficult for me to change the number of control points. This can be done for two directions – U and V, and I will increase both parameters from 2 to 5. That way I will get a few more control points located in the middle, so it will not be difficult for me to achieve my goal. Before that, of course, it is necessary to select the appropriate elements, and this can be achieved with the help of the mouse while simultaneously holding the Control key. I’m going to select these three control points and immediately place the cursor over the line that represents the vertical axis. If I then press the left mouse button, I will be able to move up and thus change the shape of the entire surface. This change must be very small because I would not want large deformations to occur. To successfully complete this task, I just need to press the Esc key and terminate the command. If I show the whole model from the side, you will see that there is a small bulge in the middle of the courtyard, which is exactly what I wanted to achieve. In the end, I just need to select the option Hide CV to turn off the display of control points and thus complete this lesson.