Hello Again Everyone! This is time for ghouls, ghosts and
things that go bump in the night. So, this week I will give you
some ideas for your Halloween images. I will begin with a quick
modeling of a pumpkin and then some tips on ghost shaders. Note:
the following techniques are specifically for Alias Maya, but they
can also be applied to other applications. Creating The
Pumpkin For the pumpkin I started out with a sphere. As you can
see on the image below, it has 32 sections that will make life
easer. To create that "creasy look" I select the CVs as shown on
the second frame, and then I scaled it down until I get what you
see on the third frame. Next, squash it a little to get the pumpkin
proportions, as seen on frame four.
In the next image, you can see I have circled two groups of CVs.
Select the CVs inside the blue circle and scale down in the Y axis,
so you get something similar to what you see on the first frame on
the image below. It looks more like a pumpkin but the top section
looks too planar. To solve that, select the vertices outside the
blue circle (the outer ones), and scale up in the Y axis. Now that
the planar look is resolved, you will have a proper pumpkin shape,
like the image in frame three.
The pumpkin is finished but we have to make the stem. For that I
used a cylinder with 16 sections. To get that irregular appearance
of a real pumpkin stem; I moved the CVs in a row, then I gradually
scaled down each CV level to get the final look. As you can see the
object is hollow so I selected the edge isoparm and used the
"planar" command to cap that hole. Now put everything in position
and you are done. You can now delete the history if you want.
Ghost Effects Now, onto the ghost effect I based the look
on Casper as well as the Final Fantasy Spirits,
within phantoms. I think that look is better than just printing the
whole figure at partial opacity (setting the opacity layer in
Photoshop to something other than 100%). To get the Casper look I
used a ramp to control the opacity of the material. Create a ramp
and a sampler info node and open the Connection Editor. Use the
sampler information as input (left), and the ramp as output
(right). Next connect the facing ratio to the ramp U and V
coordinates. Just a reminder; black is fully opaque, while white is
fully transparent. I used the setting to make the object opaque at
the edges, but the gray stripe at the bottom serves to blur the
geometry edge.
For the color I used the brownian1 texture. You can use pretty
much anything you want depending on the look you are after. I stuck
to the orange color because it's a pumpkin, but if you were to
apply this to a character you could very well use a file texture
for the skin. Remember that you decide the final look of your
characters and objects, so don't be afraid to go wild when creating
your textures.
When you are happy with your shader, you can apply it to your
object, and click the render button. The next image shows the
result after layering the ghost pumpkin on top of an image. I like
to think that the final render is only half way there because I
usually like to post-process my images. To get a better ghost
effect, you could use different blending modes until you are
satisfied with the result. As you can see, the left pumpkin looks
horrible when you put it on top of the background. However, the one
on the right looks more ethereal, which is what we are striving
for.
This is the end of the five-minute pumpkin if you create an image
using the above tips and tricks, please post a link to your gallery
images in the comment section below. Wishing everyone a happy
Halloween! Check back for future seasonal mini-tutorials. Keep
Animating! Sergio
 Animation Alley is a regular featured
column with Renderosity Staff Writer Sergio Rosa [nemirc].
October 17, 2005 |
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