• The "Ball" tool deforms the surface as though a sphere is pushed into the surface. If the ball is smaller than the Freehand object, then only part of the surface will be affected, as though the surface was easily stretchable.

 
• The "Knife" tool affects the whole surface, but the effect on a particular point in the surface reduces with the reciprocal of the distance of that point from the centre of the tool.

1. In "select" mode, select the Freehand component. There must be only one component selected, and this must be a Freehand object.
2. Change the mode to "model" and select the desired tool with the optionmenu.
3. Click and drag M1. An ellipsoid opens up. The ellipsoid has a different meaning depending on the type of tool:
• For the "ball" tool, the ellipsoid represents the surface of the ball.
• For the "knife" tool, the ellipsoid represents the distance from the centre of the tool at which a point on the surface moves by half the amount of the modelling handle. Recalling that other points are affected in proportion to the reciprocal of their distance from the centre of the tool, a point half-way between the centre and the ellipsoid will move by two-thirds of amount of movement of the modelling handle.
4. On releasing M1, a modeling handle, depicted as a red dot will appear. This can be dragged with M1. On releasing M1, the surface will be deformed.

In the examples above, both the creation of the Freehand object and the definition of the modelling tool were done in the same view. But it is often useful to define the modelling tool at right angles to the surface. The surface is then modelled identically in one dimension, as illustrated in the following example.

Resolution

Freehands are Single Sided

As surfaces are deformed, this assignment can change. If a Freehand component refuses to render correctly, the user is advised to check first of all whether the problem is that it is only visible from the other side. This can be determined by moving the StdCamera to verify this hypothesis. In the following example, the main wing was created in the Side view and pulled outwards with the ball tool. It was found necessary to rotated it through 180 degrees in the side view before doing this however. As another example, a common use of a Freehand object is to represent the sky over the scene. Note that you cannot simply enclose the scene inside a large ellipsoid - these are not visible from inside! However, a Freehand object may be created in the Plan View, rotated through 180 degrees in the Front View, and the "Ball" tool used to form a hemisphere.

Freehand objects are much more difficult to use than the simple objects such as Cuboids, Cylinders and Cones. One problem is speed. Each transformation of a Freehand object, and even selecting and deselecting it can take a long time, particularly if large resolutions are being used. This is in part due to the sophisticated datastructure used to represent the network of Polygons, which was originally designed to allow the user to edit any single vertex, while keeping the polygons comprising the Freehand object joined at their common edges.