Optional Files
If enabled, the respective objects that are hidden for rendering will also be exported in a hidden state. Alembic only recognizes visible and hidden states for the Viewport and rendering simultaneously. Therefore, both hidden settings will be set to red in the Attribute Manager upon import.
Enable this option if you want to export the particles together with any related polygonal objects (only these will be rendered). When using Thinking Particles, make sure that you assign geometry using 
TP Geometry. This will ensure that subsequent Alembic imports will work better.
If enabled, a Hair object’s Guides will be exported as Splines (curves). If the Hair object’s Type is set to Spline, the hairs can also be exported as curves.
Enable this option if you also want to export XRefs. If this option is disabled, the entire XRef hierarchy will be excluded (incl. all non-XRef objects in the hierarchy).
Use this option to define whether or not vertex Normals should be exported (even if no Normal tags exists, these will be created internally upon export).
Enable this option if UV coordinates should also be exported.
Enable this option if Vertex Colors should be exported. For multiple Vertex Color tags, make sure that they have unique names (Alembic cannot handle identical names).
Display Colors to Vertex Colors
This option can be used in conjunction with the Display Color to export colored objects as vertex colors, for example, to export colored MoGraph objects.
Enable this option if Vertex Colors should be exported.
If this option is enabled, Vertex Maps can be exported as vertex colors (Maya can, for example, import these files vis the -rcs option). Multiple Vertex Map tags can be used, which should however each have a unique name. Otherwise only the last tag will end up in the Alembic file.
Enabling this option will export a mesh as a vertex cloud (without polygons).
Vertex colors will also be exported (as long as the Vertex Color tag’s Vertex Color setting is set to Only Points).
Cache objects that are, for example, created using Generators (e.g., Cloner or Symmetry objects) can be merged into a single mesh upon import (like a Cloner object that duplicates an object 10,000 times), which can be loaded into Cinema 4D much faster and be displayed more fluidly.
Careful: Parametric primitives are also Generators and can be merged as well.
Note that if this function is used with the same Generator on various types of objects (e.g., splines and geometry), only one type can be exported.
If this option is enabled, multiple UV sets (tags) will not be supported.