"All too often textures are overlooked as a
solution for creating effects. The tendency is to think
of textures
as simply a means for col- oring objects. The tutorials in this first chapter demonstrate some ways in which engaging visual effects can be created quickly and easily simply by taking advantage of the power that textures have to offer"
Create Animated Effects with a Ramp Texture
This first challenge involves adding
an effect to the opening shot of an animated short. Figure 1.1 shows part
of the storyboard for the opening. The camera
moves downand out to reveal a dilapidated hotel sign with some broken lights. The gag is that the lighted parts of the sign spell “Hell.” The neon vacancy sign is just barely
hanging on. The director would like to suggest that
the hotel is possessed
by demons, so as the cam- era stops, the Vacancy
sign lights up, one of the bolts gives away, and the sign swivels so that
the arrow points downward. Subtle, no?
Figure 1.1 The storyboard
shows
a neon sign
magically coming
to life.
Rather than have the sign blink
on like a real neon
sign would, the director would
like the light of the neon Vacancy
sign to start at the letter V and travel to the end over the course
of about a
second.
A particle effect should
be added to the leading end of the light.
The sign has already
been modeled, and the basic camera move, along with the animation of the broken sign, is established. For the Vacancy
sign, there
is a NURBS curve but no neon geometry as of yet.
This effect should be fairly easy to create
by extruding geometry along
the length
of the curve. A shader
can be applied to the geometry, and then an animated ramp attached to the incandescence of the shader will provide the lighted effect. Whenever you’re confronted with an effect, it’s a good
idea to design a rig with a few simple controls that
can be easily animated. Whenever possible,
the rig should be setup to anticipate changes as easily as possible
because
art directors are fussy and tend to
change their minds
a lot. This tutorial will take you through the steps of setting
up a
rig so that
one control can be used to animate the light traveling along
the length of the word
Vacancy as well as the position emitter for the particle effect.
This exercise demonstrates one way of creating the rig and introduces you to several methods for navigating the node
hierarchy in Autodesk® Maya®. Every Maya artist
has their own style of working, but once in a while it’s a good idea to explore alternative methods of navigating the Maya
interface. Doing
so will open possible workflows that
you may not be aware of, which
can increase your efficiency as well as your understanding of how Maya works.
Create the Sign Geometry
The geometry for the Vacancy
sign can be extruded along
the existing
curve in the scene. Before you start extruding geometry using NURBS geometry, I suggest you consider applying a Paint
Effects stroke to the curve and then convert
the stroke into polygons. The reason
for this is that
it’s easier to control the twisting and pinching that may occur as the geometry follows the curve. In addition, the UV texture coordinates created
by the Paint Effects geometry will be easily adapted so that the ramp that
creates the neon light can be animated without too much
work.
1. The project files for this chapter can be downloaded from from the book’s
support site.
Use your web browser to navigate
to www.sybex.com/go/mayavisualeffects2e and download the Chapter01_project. Once the files have been downloaded, unzip them to your local drive. Open Maya
and use the File menu to set the Project to Chapter01_project. Then open the signSTart.ma file located
in the Scenes directory of the Chapter01_project file directory. Once the scene is open,
switch to the Persp camera
using the View menu in the main viewport.
2. In the Outliner, expand the vacancy_sign group, and select the curve node named
vacancyNeonCurve (see Figure 1.2).
 |
| Figure 1.2 Select the vacancyNeonCurve node in the Outliner. |
3. Switch to the Rendering menu set, and choose Paint Effects c Curve
Utilities c Attach Brush To Curves (see Figure 1.3). The default stroke, which is a thick black line, is applied to the curve.
Figure 1.3 Use the
Paint Effects menu to
attach the default
brush stroke
to the curve.
4. Select the Stroke1 node
in the Outliner, and open the Attribute Editor.
5. To convert
the stroke into geometry, choose Modify
c Convert c
Paint Effects To Polygons
c Options; in the options, turn
on Quad Output and Hide
Strokes.
6. Maya creates a new node for the converted geometry and places it in a group called brush2MeshGroup. Expand
this group, and select the brush2Main node.
Press Shift+P to unparent the mesh, which moves it out of the group
brush2MeshGroup.
7. Double-click the brush2Main node
in the Outliner so it becomes
highlighted, and rename the brush2Main node
to vacancyNeonGeo. You can select and delete the brush2MeshGroup node
(see Figure 1.4).
Figure 1.4 Convert
the
Paint Effects stroke
into polygons. Ungroup
the
node,
and
name
it vacancyNeonGeo.
Make sure you do not delete the Stroke1 node
and don’t
delete the history
on the vacancyNeonGeo node.
Since the stroke is applied to the curve that is contained inside the vacancy_sign group, which is keyframed, the vacancyNeonGeo node will inherit
the animation (see the sidebar
“Construction History” for information on
how this works). The advantage of keeping the history
on the vacancyNeonGeo node
is that you can change
the width
and other
attributes of the vacancy geometry by tweaking the settings on the stroke1 node.
This is helpful if a picky art director decides changes need
to be made to the sign at some point
in the future.
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