Default Shader Config
During FBX import, no automatic shader assignment for the imported scene is performed. This means the imported nodes have no shader attachments in the node appearance, and rendering is done according to a default shader configuration as specified in the Default Shader Configuration dialog (See below image).
Same default shader configuration is applied during asset generation, for all nodes having no shader program explicitly assigned.

The default initial shader values for each 3D object type are shown in the table below.
CanvasTransShaderParamSetter
CanvasSpriteWith1Texture MeshWithNoTexture RefTransLight1_RefColor TransLightShaderParamSetter
MeshWith1Texture RefTransLight1_RefColorTex MorphingMeshWithNoTexture RefTransLight1Morph_RefColor TransMorphingMeshShaderParamSetter
MorphingMeshWith1Texture RefTransLight1Morph_RefColorTex PlanarShadow RefTrans_RefUniDiffuseMat TransUniDiffuseMatShaderParamSetter PointSprite RefTransPointSprite_RefPointSprite TransPointSpriteShaderParamSetter SkyBox RefTransCubeMap_RefCubeMapTex - CanvasText - TransLightShaderParamSetter