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596 Chapter 20: Managing Scenes and Projects
Animation
B eware of large file sizes whenyou use transfor m
anim ation and coordinate-i nterpolated
animation. The VRML97 plug-in exports
transform animation (move, rotate, and scale),
and coordinate-interpolated animation. For
example, you can animate modifiers such as
Taper and Bend and you can animate changing
parameters, such as increasing or decreasing the
radius of a sphere.
When scenes using the In her it Lin ks f unct ion
areexportedtoVRML97,childobjectsalways
inher i t t heir pa rents’ t r a nsfor ms. Inverse
kinematics export correctly to VRML97 with the
exception of the Inherit Links function, which
determines whether child objects inherit the
transforms of parent objects.
Always u s e TCB cont rol le r s f or VR BL
animations. These controllers pro vide precise
control and generate the smallest possible file size.
Other kinds of controllers, such as the default
Bezier controller, create larger VRML97 files that
do not perform as well.
Ma ke sure your a nimat ions never change the
face or vertex count over t ime. VRML97 can
not add or delete faces or vertices over time.
CoordinateInterpolators support morphing a
mesh only, not changing the number of vertices
or faces.
To t r i g g e r a n a n i m a t i o n t h a t i s n o t o n a n
object at the top-level of the software’s link ing
hi er a r chy, u s e a Tim e S ens or helper object. If you
trigger an animation directly from a TouchSensor
or ProximitySensor, without a TimeSensor, you
can animate only top-level objects. Animating
from TimeSensors does not hav e this limitation.
Turn off the Generate Primitives toggle
in the Expor t dialog if you animate the
parameters of primitives (like the radius of a
sphere), and want the animation exported with
CoordinateInterpolators. This applies to box,
sphere, cylinder and cone primitives only.
Materials
You can export only standard and multi/sub-object
materials, and only the following components of
the material:
• Diffuse, ambient, and specular color
• One texture map, which must be in the Diffuse
channel
UseJPEGorPNGformatforyour
maps, because they are recognized by a ll
VRML97-compliant browsers and generally
create the s ma llest files. (Some older browsers
may recognize GIF format and not PNG.)
Multi/sub-object materials export colors and
textures. If an object has a multi/sub-object
material with textures, it exports as separate
objects in VRML97, since VRML97 does not
support more than one texture map per object.
Texture maps slow down the browser and
increase download time. Use them sparingly.
• Shininess (but not shininess strength)
•Opacity
• Wire f rame
Make sure that all large flat surfaces have enough
vertices in them that a few vertices can b e seen
from al l reasonable vantage points in your scene.
Some browsers cannot display textures on an
object where all of its vertices are outside the
cur rent viewport.
If you have severa l l ig hts in you s cene, lower t he
def ault multiplier value on all the lights in t he
scene. Lights can oversaturate the scene and make
all your geometry w ash out toward white. Always
add at least one c amera and one light to a scene
exported to VRML97.