Programs used :
pIllusion from Wondertouch : http://www.wondertouch.com/
( free demo available )
ComPath from Trionix : http://www.tpp.le-site-web.com/
(Screenshots are Compath version2)
In this program, we will create the path by adding a bouncing
path to a spiral trajectory.
By default, ComPath opens with the "Screen"
tab and a proposed resolution of 320/240 pixels.
Accept this. ( or change the resolution if you want.)
We will work with negative value, so set the margin to 60 to see
what's happend "outside" the screen area.
Margin=60
The resolution and margin do not affect the path you will create.
They are only a visualisation help.
Click on the "Rotation" tab. A blue circle
appears on the screen.
This circle is the first of the four preset.
We will start with the "Spiral" preset , click
the corresponding button in the preset panel.
You can see a lot of parameters in this tab.
Now i will explain some values
Distance : this is the common radius (in pixels) of the circle,
or the distance between the center and the first point of the
spiral (or curve).
Distance factor : each frame, the distance grows by this value
( in about 1/100 of per cent ). Set this value for logarithmic
spirals.
Distance /360degres : the distance gros by this value each 360
degres. Set this value for arithmetic spirals.
Rotation : each frame, the point turn by this value (in degres).
Rotation factor : each frame, the distance grows by this value
( in about 1/100 of per cent ).
Position : the position of the center of the circle or spiral.
Ratio : an aspect ration of the curve, between x and y.
Ratio Factor : the ratio is modified bye this value.
But first, we will set the number of frames of our animation.
In the small frame panel, at the right side of the tab, enter
300.
Frames=300
Now we will change this curve.
We wish that the emmitter begins with a high speed, and then,
slow down.
So, we will set a high value to the "Rotation" and tell
it to decrease.
Rotation=6
Rotation factor=0.9
Now, we will set the ratio to simulate perspective
Ratio=0.7
The curve go outside our frame, we must adjust the distance.
Distance=100
Now we have our trajectory.
To keep these trajectory in memory, click the "Apply"
button . (the radiobutton set to Replace, this is the default).
Click on the "Gravity" Tab.
Now, you can see the path made in #3 in black an the preview path
of the gravity tab in blue.
For now, you can hide the black path by unchecking the "Path"
checkbox at the bottom of the application.
Very important : now, we will create a "bouncing" curve.
This curve will be added to the trajectory created in #3.
"Bounce" means a variation on the Yaxis only. In the
final curve, the x value is the value of the trajectory created
in #3
(Each point of the trajectory created in #3 could be seen as the
ground level ..)
Enter now these values :
Position X=0
Position Y=-40
Ground=0
Speed X=1
Speed Y=0
Friction X=0
Friction Y=0
Gravity X=0
Gravity Y=0.3
Now you see a nice bouncing curve at the 'top' of the screen.
You can increase the number of bounces by increasing the Gravity
Y and the FrictionY values.
In order to add this curve to the trajectory, the Position X value
must always be 0, so the speed along x-axis must be set to 0.
Speed X=0
The curve looks like a little vertical segment.
Now Check the "Add" checkbox.
You can see now, the prewiev of the final path.
If you think it looks good, then click on the "Apply"
button.
( If not, choose the replace button, and set the Position X to
a value in order to see what you will change.
You can also change directly in "add" mode. But sometimes,
it is hard to do.)
When you click the "Apply" button, the final path is
added, and a new blue path appears on the screen.
This new path is the path you will get if you push the "Apply"
button again, and so on...
To see your path, check the "Path" checkbox,
and uncheck the "Preview" checkbox at the bottom
of the screen.
To visualise a particular position of the path, check the "Markers"
checkbox, at the bottom of the screen and choose a frame number
with the slider.
A small colored point will appear on the curve. It represents
the position of the emitter at that frame.
Click on the "Load / Save" Tab.
Choose the frame number of the first path position. I leave it
on 1.
Click on the "Save as" button. Type a filename...
Quit ComPath.
Run pIllusion.
Add an emitter to the stage. I suggest the "Shooting
Stars Trails"
Set the zoom value of the emitter to 10
In the hierarchy window, select the emmiter, right-click on it
and select "Import" and "Position data"
from the menu.
Choose "Tab-delimited text (from file)" and select
the right file.
Your path is now on the stage.
Push the "Play" button to see the effect.
download the .ipf here : bouncing.ipf
That's all.
If you find that your emitters move too slow :
-Run ComPath
-Load the path you created. ("Load/Save" tab)
-Choose the "Transform" Tab
-Set the "Frames" value to 150 and click on "Stretch"
button
-Save your path ("Load/Save" tab)
-Import it again in pIllusion. The emitter will fly two times
faster.