Adding polygons
For this tutorial we are going to create a very simple fish. This is a convenient 3D model
to produce from scratch because it is relatively flat and much of the time we will be working
in 2D.
We will add polygons one by one using the Add Polygon function. Load 3DMatrix and ensure that
the 'XY Orthogonal View' window is open (shortcut 'z'). Use the '3DMatrix' window to control
which other windows are opened. Next open the Polygon Properties window (shortcut 'p') and
press the 'Add polygon' button to add our first polygon. It is worth remembering the keyboard
shortcut 'a' for adding polygons.
While adding polygon, as you move the mouse cursor over any of the Orthogonal View windows you
will see the vertex cursor appear as a small red square. You can click in three different
places to define the three vertexes and create the first polygon.

Note that because windows are 2-dimensional they can only define two axis positions. The
third axis position is determined by the position of the yellow Locator in one of the
other two Orthogonal View windows.
Let's say that we want to place the vertex near Z = 3. This can be done by pressing the mouse
button over the horizontal yellow Locator line and dragging it upwards within the XZ Orthogonal
View window.

Alternatively you can open the Locator window (shortcut 'o')
and type '3' into the Z input box.
Now click three positions within the XY Orthogonal View window to produce our first polygon. Notice
as you click each new vertex the previous vertexes remain shown. You can cancel the Add Polygon
operation by pressing ESC.

After selecting the third vertex the polygon appears filled in light gray. Repeat the process for the
second and third polygons, specifying the first two vertexes over the top of vertexes within previously
produced polygon. The red vertex cursors will jump to the precise position of other vertexes that
are close in all three dimensions.

To delete a polygon, first select it by clicking near its center. You can select multiple polygons in
this way by holding 'Shift'. Then press the 'Delete' key to delete all selected polygons. An alternative
way to select polygons is to hold the 'CTRL' key (or choose 'Select Polygons' from the 'Selection' window)
and press and hold the mouse button over an Orthogonal View window and drag the blue selection box
to completely surround the polygons that you want to select.

Polygons are selected for the purpose of deleting or coloring them. If you want to
move or transform polygons you need to select their vertexes. Vertexes are selected by first checking
that 'Select Vertexes' is chosen from the 'Selection' window. Then press and hold the mouse button over an
Orthogonal View window and drag the green selection box around the vertexes that you wish to select. Selected
vertexes appear surrounded with small green boxes. You can hold 'Shift' to accumulate multiple selections.

When vertexes are selected they can be dragged to new positions by pressing the mouse button over
one of the green boxes and dragging it. All selected vertexes will be dragged at once. Positions
can be entered precisely using the Vertex Mover window (shortcut 'm').
Now we may proceed to draw many polygons for one of the fish's sides.

It is necessary to define polygons throughout the fish so that we can give it a depth. Select
polygons in the middle and drag their Z value upwards within the XZ Orthogonal View window. Make
sure that you don't change the Z value for polygons that lie on the edge of the fish. In our case
there are only three vertexes that provide the fish's depth.

You can move the left-most selected vertex that defines the fish's tail thickness downwards so that
the tail is thinner than the body.

Now is a good time to save your work. Open the 'File' window (shortcut 'f')
and enter a filename into the input box and press 'Save'. 3DMatrix 1.3 does not have an undo feature so
it is useful to save your work regularly.
Next we create the fish's opposite side. Open the 'Component'
window (short-cut 'c') and select 'Copy'. Then select all the vertexes belonging to the copied
component by pressing the lower 'Sel' button within the 'Component' window. We are going to flip
the fish's second side against Z plane that cuts the fish in half.
Open the 'Transform window' (shortcut 't') and make sure that Transform about 'Locator'
is selected. Next make sure that the Locator's Z value is through the middle of the fish as
shown below in the XZ Orthogonal View window. (If you are not sure, select an individual
vertex on the outer edge of the fish, open the 'Vertex Mover' window (shortcut 'm') and observe
the 'Z' co-ordinate. Enter the same Z value within the 'Locator' window).

Now the component can be flipped by pressing the 'Z' button in the Transform window's 'Flip' section.

Understanding polygon surfaces
We will see how the fish looks from the Perspective View window. Open the 'Camera' control
window (shortcut 'r'). If you are familiar with flight simulator games then the camera can
be handled easily using the arrow keys along with ',' and '.' to move the camera forwards and
backwards.
The easiest way to navigate the camera is to use the Pos (Position), Dir (Direction) and
Rot (Rotation) buttons within the 'Camera' window. These 'Pad' buttons allow you to change
two parameters at once by holding the mouse button over the button and moving the mouse
up and down, left and right to vary the parameters. It is worth practicing with these three
Pad buttons for a while until you can move the camera around quite effectively. After only
few minutes you will be an expert.
As we move close to the fish we can observe that some of the polygons are dark and other
polygons are light. This is because polygons are single-sided; some are facing away
from the camera and some are facing towards the camera (their direction was actually
determined by whether the vertexes were added in clockwise or anticlockwise order). Light
is only reflected from polygons that face towards the camera.

We want all polygons to point outwards from the center of the fish. You may firstly
select all polygons by clicking both 'Sel' buttons within the 'Component' window while
holding 'Shift'. To point the selected polygons outwards from the center of the fish
you can open the Polygon Properties window (shortcut 'p') and click the 'Face polygons
against Locator' button. Make sure that the Locator is positioned at the very center
of the fish within each Orthogonal View window. To show clearly which direction the
polygons are pointing, open the 'Light' window (shortcut 'l') and select 'Highlight reverse
side of polygons'. Polygons facing away from the camera will now be shown in bright
green.

A polygon at the tail is shown still facing the wrong direction. Selecting just this
polygon and clicking 'Reverse direction of polygons' from the 'Polygon Properties' window
will correct this. Polygons can also be selected from the Perspective View
window by clicking them, which makes identifying and flipping green polygons very
convenient.
Now fly the camera right through the fish and out the other side and select 'flip' from
the 'Camera' window to face the opposite direction. We are now looking at the other side of
the fish, but it appears dark because the light source is on the other side. There is also
another polygon that is facing the wrong direction, shown in green, which needs to be
selected and reversed using the 'Reverse direction of polygons' button.

In making refinements to the fish we can fly to the front and observe that our fish appears
too fat. This can be adjusted by selecting the outer vertexes from the XZ Orthogonal View
window as illustrated below and dragging the vertexes inwards. If you have selected too many
vertexes then you can deselect vertexes by holding 'ALT' while dragging the selection box
(which now appears red) around the vertexes you wish to deselect.
(NB: To ensure you are only working with vertexes from one side of the fish you can hide one
of the sides by toggling the component visibility check-boxes within the 'Component' window).

The fish's mouth can be opened and closed by selecting the two polygons at the front of the
fish and using the 'Transform' window's '+' and '-' Scale buttons to bring these two vertexes
closer together and further apart. Remember to make sure that 'Transform about center'
is selected at the bottom of the 'Transform' window.

To finally give the fish some color we can use the Polygon Properties window. You need to
select all polygons by shift-clicking the two 'Sel' buttons within the Component
window. Enter the red, green and blue color range values of your preference within the
Polygon Properties window. Click the 'Apply' button until you find a set of colors
that appeals to you, altering the color range values as necessary. That's it! A simple
3D fish model.
