exposedField SFNode material NULL
exposedField SFNode texture NULL
exposedField SFNode textureTransform NULL
The Appearance node specifies the visual properties of geometry by
defining the Material and texture nodes. The value for each of the fields
in this node can be NULL. However, if the field is non-NULL, it shall
contain one node of the appropriate type.
The material field, if specified, shall contain a Material node. If the material field is NULL or
unspecified, lighting is off (all lights are ignored during rendering
of the object that references this Appearance) and the unlit object
colour is (1, 1, 1). Details of the VRML lighting model are
in "2.14 Lighting model."
The texture field, if specified, shall contain one of the various
types of texture nodes (ImageTexture, MovieTexture, or PixelTexture).
If the texture node is NULL or the texture field is unspecified,
the object that references this Appearance is not textured.
The textureTransform field, if specified, shall
contain a TextureTransform node. If the texture field is
NULL or unspecified, or if the textureTransform is NULL or unspecified,
the textureTransform field has no effect.