Graphics Programs Reference
In-Depth Information
Figure 13.11
Figure 13.12
tab. Replay the animation and you'll see that all the particles emitted move fairly rapidly
along the
y
-axis of the scene (Figure 13.11). You have just told Blender to emit the particles
along the
y
-axis at 10 units per second instead of emitting them at 1 unit per second at 90
degrees (normal) to the face on the surface of the sphere. Note that “Emit From Faces” in
the “Emission” tab is activated (Figure 13.12).
The forgoing example has demonstrated how a particle system is instigated and can be
controlled by values in the “Particles” tab. We will leave these buttons alone for the time be-
ing and come back later. Let's now look at where and how particles are emitted from an ob-
ject. In the properties window - “Particles” buttons - “Emission” tab, note the “Emit From”
buttons: “Verts” (vertices), “Faces,” and “Volume.” The default value “Faces” is highlighted
in blue. To see the effect of these buttons, start with a new Blender scene and delete the de-
fault cube. Add a plane object and remove the 3D manipulator widget (removing the widget
will let us see more clearly what is happening when particles
are emitted). Untick the “Gravity” button in the “Scene” tab
and add a particle system to the plane. Press Alt + the A key
and play the animation showing the particle generation. You
will see the particles being generated on the face of the plane
object (Figure 13.13). The particles are being generated at an
initial velocity of 1 unit per second normal to the face of the
plane (at 90 degrees to the surface), which is in accordance
with the default values in the “Velocity” tab.
In the “Emission” tab - “Emit From” buttons, select
“Verts” and replay the animation. You will now see the
emission of particles from the four corners of the plane
(Figure 13.14). Selecting “Faces” or “Verts” depends on
what you want to see in your final render.
We will now investigate particle generation. Start over
with a new Blender scene and delete the default cube object.
Figure 13.13
