It is a schematic model of a hydrogenerator. Let us assume, that we have already loaded the file and connected it to the project. (Similarly to previous lesson, you can download vdr file here)

The barrel represents the separate object, and has the name object01 (you can see and change the name in the dialogue Properties of 3d object. To open the dialogue just double click the mouse on the object). Besides the shaft of the generator is also represented as the separate object (object02) and its  Y axis passes precisely on rotation axis of the barrel. Let us rotate the barrel according to the Y-axis of the curl.

For this you should add the object Rotate3d . Then link its HSpace3d with the same variable of the object Projection3D. It specifies the number (descriptor) of three-dimensional space. Now set in the variables  Rotate3d object values:

Var name value description BaseName object02 object name, in the local coordinate system of which evolution changes of the object take place. ObjectName object01 Name of the controlled object AxisY 1 Rotates according to OY axis

For rotation create a new object with the following formula:

Angle: = Angle+da.

Let us link the variable Angle of the new object with the same variable of the object Rotate3d. Let us set value da equal 0.5.

Now let the project run.

The rotated curl should be displayed on the screen.

Add the object VSlider to control the rotation rate and the  value da.

The project you have got looks like the following: