Freehand Components

The freehand object is an arbitrary three dimensional shape that you can place in your drawing. Freehand objects may be redimensioned, scaled and rotated, and coloured with the different shader types provided in the same way as Cones and Cylinders. On creation, it is a flat surface, but the TSIPPwb allows you to mould it to the desired shape with the mouse using one of two Modelling tools:
For both tools, the procedure for using them is the same:
  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:
  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.


The resolution of the Freehand components may be specified on the Edit page in terms of the number of rows and columns of interlocking hexagons used. However, changes to these entryfield values only affect the resolution of Freehand components created subsequently: once a Freehand object has been created, the resolution cannot be changed. Note that increasing the resolution slows down the program dramatically. Even with a 1700 MHz AMD Athlon processor, 16 * 16 is the largest practical resolution.

Freehands are Single Sided

Freehand surfaces are rendered on one side only as specified in the following table:
View Surface initially
visible from ...
Front in front
Plan above
Side the left

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.