Making an "octopus" emitter -- by accident 23 Jul 00
(or "How I make most of my emitters")
Page 2
Continuing with the cool worm emitter theme, I tried another snake image:

I created an alpha channel (by hand) again, but this time I didn't make it round -- I left the
whole snake body intact. This was not because I knew exactly what it would do, but was just
how I did it. No real thought behind it, but it was an important choice (as I would find out later).

Using this image for the particle shape of the "big fat worm" emitter, I ended up with another
big fat worm, but with what looked a little like "tentacles" in one part of its body, and a big
fat "belly" on the other side.

This one really creeped me out, but again I could NOT stop dragging it around the preview window. So cool and flowing,
plus the use of the snake image added a lot of "texture" to it. After ten minutes of playing in the
preview window, I started scrambling for more snake images. I needed MORE. I made about 3 more different
"worm" emitters. One of them had a "notch" so that you could actually see "inside" the worm.

Wow! That got me thinking again. What was making the "tentacles" of the previous emitter, and what was
making this "notch"? I started doing a lot of experimenting with the brown snake image -- removing various
parts (with an alpha channel) and seeing what would happen. I really went through a lot of iterations on this, and
came up with this special "test" shape to prove it to myself:

This resulted in the following emitter which allowed me to clearly see what was going on (and was
pretty cool to look at too):

It was at this point that I realized that I already knew how to make tentacles -- I had made them in the
"Space Jellyfish" emitter. Why didn't I think of that sooner? I guess I was too excited by the look of
the new "worm" emitters to think straight. =) Anyway, after some more tweaking, I modified the snake
image to look like this:

Which resulted in my "octopus" emitter:

There is one last "trick" that I came upon when playing around with the various snake images. It involves
the particle colors. All of these examples had the color start black then go to white (so the "head" of the
worm is black and the rest is the color of the shape images). By setting the color "repeat" slider to
3 or 4 clicks up and making the particle color go from black to white more slowly, then white to black slowly
at the end of the particle life, I thought it looked a lot like the "octopus" had shadows playing over it.

That was the final touch to make the octopus appear even more creepy.
So you now have an idea of how I went from one idea for an emitter to something completely different,
but exceptionally cool! Is there a lesson to be learned here? Yes: Next time I say I just come up with
emitters by accident, believe me! No, the real lesson is: don't be afraid to experiment. Change parameters, change shapes,
change colors. Do all of that, and have fun with Illusion!
(Note: Notice how all of my particle images have a little white "halo" around them? It adds
a neat little "edge glow" to the tentacles, but if anybody knows how to avoid this, please
let me know. I don't want that glow all the time, and I'm not the best with paint apps and alpha channels.)
Back to Page 1
The project and image files:
(238 KB)
(These project files CAN be loaded by the demo version of Illusion.)
Alan Lorence 23 Jul 00