Amiga Format CD 28/amigaformatcd28.iso/-in_the_mag-/workbench/tornado3ddemo/tutorial.txt

Text File | 1998-05-13 | 6KB | 110 lines

Loading pre-made objects/scenes.

Some sample scenes are provided. In order to open a project, start Tornado3D, use the Open... menu item in Projects
menu and when the project has loaded switch to CAMERA mode pressing the 'e' key.

Tutorial 0
Let's see something in no-time.

Particles are often used in animation by means of the so-called Particle Systems that allow a coherent and
realistic movement tied to physical laws.

By the means of the particle systems many effects otherwise impossible to model --like fire or smoke-- can be
simulated in a convincing way.

Starting with a new, empty project, we add a particle system with the Objects/ Particles/ System... menu item.

This opens the Particle Panel, leave everything at its defaults, so that an "Explosion" particle system will
be created. Accept the panel and redraw the screen with Amiga-r.

Now press the TAB key or click on the cycle gadget Modeling/ Animation to enter animation mode. Then click on
the Play Forward gadget of the VCR bar to see a preview of the effect. Hey, who said that to use particle
effects you had to be a rocket scientist? :)

Now press '3' to switch to a shaded preview mode and click with the mouse the Play Backward VCR button. You'll
enjoy a color preview running from last to first frame.

Now return in modeling mode pressing TAB again and select the particle system with Amiga-A. Then, delete it
with the DEL key.

Tutorial 1
First steps with the editor

Interacting

Start Tornado3D or open a new project replacing the existing one with Project/New.

We are now in Tornado3D's main editor. With Objects/ Polygonal/ Pyramid we add to the workspace a new object.
This is a polygonal object, that is, one composed of vertices and faces.

Press the key '3' or use Workspace/ Preview/ Flat Shaded to immediately show a color representation of the
object.

The pyramid looks like a white triangle, and this is due to the camera angle we are using. Let's look at it
from another point of view, but before let's move the mouse --without clicking-- over the perspective view.
Nothing should happen.

Press the 'r' key on the keyboard now or we use the menuitem Modify/ Transform/ Rotate. This way we have
entered rotation mode. Let's move again the mouse over the perspective area, as before. Now a yellow circle
appears. This yellow circle is the reference mark of the "Arcball" rotational controller. It really is very
simple to use and learn.

Now click with the left button in the perspective view, just outside of the circle and then drag, holding down
the mousebutton. We should try to keep the mouse pointer outside of the yellow circle, in practice rotating it
around the object. We will see that the object follows our movements and that a brighter yellow line provides
a graphical representation of our actions.

Now we release the mousebutton. The object will stop moving. If we look at the other --non perspective--
views, we notice that the pyramid has not been modified. What has changed is our point of view. Now we repeat
the operation, but this time we click inside the yellow circle.

A line now appears, departing from the point where we have clicked. This time the line follows our movements
and is not confined anymore to the circle. This allows us to freely rotate the object. If we trace back our
steps, moving the mouse up to the point in which the curved line originates, the object will return exactly to
the position of departure. This fact, apparently not very important, is really an unique characteristic of the
Arcball rotation controller that allows to rotate the objects in three dimensions using a device, the mouse,
that is two-dimensional.

All the other rotation systems, and Tornado3D is the only Amiga software to implement ArcBall, manifest a
behavior, the so-called Hysteresis, that makes impossible to trace back the movements and this leads to a
counter- intuitive user interaction. With Arcball, everything is like in the real world. Moving the mouse to
the left, rotates the object to the left. Moving it in circles around the object, rotates the object.

In order to understand better the idea behind the Arcball, let's try to imagine that the yellow circle is the
profile of a sphere (the sphere of a trackball) and that the mouse acts like our hand. The curved line that
appears when we click inside the circle is curved because it depicts the movement of the hand on the surface
of this virtual Trackball.

Modifying

Now restore the perspective view to its original values with the menuitem Workspace/Set View and we are ready
to discover how to modify objects.

Let's click on the center of the object's axis, that is on the small square from which three lines depart
marked with the X, Y and Z letters. The object will become white, to signal it is selected and ready to be
acted upon.

Press 'm' on the keyboard to return to movement mode (remember that we switched to rotate mode before, to try
out Arcball).

Now click and drag with the left mouse button, but not over the object axis! As a general rule, we must always
click on an empty spot to start an interactive operation.

The object will move along with our movements, following the mouse. If we release the mousebutton, the object
will remain where we placed it. Now the modification is permanent, but it can be undone with the Edit/Undo
(Amiga-Z) command.

We will now repeat the same actions but first press Shift-X to force the movement to happen only on the X
axis. We have activated a constraint. Now the object will move only along the X axis.

Now try to resize the object with the scaling function. Press 's' to switch to Scaling mode. The constraints
are automatically reset. We do the same thing we did before, clicking and dragging. This time the object will
not move, but will be magnified or shrunk according to the mouse movements.

We are already familiar with rotation, having tried it in the perspective window. Now try to rotate the
objects instead of the viewpoint. So press 'r' again to go back to rotate mode, and proceed as usual, clicking
in an empty spot of the non perspective-views. The object will rotate on the selected axis. Repeat the
operation with other axes, for instance Z axis. Now our object is not aligned with the world axes anymore.