3D Modeling

[cropawrafr]

Hi,

we have some questions regarding the history stream.
We have read through the documentation, but this is not fully covered by the the documentation.

We assume, all bulletin boards during modeling operations are created in the default history stream.
I also assume in most applications the default history stream and the history stream of the
part are identical.
Operations on the part's history stream (roll operations) modify all entities whose bulletins
are in this history stream.

For a certain reason we wanted to have entities which are not Freeware added to the part and should not
be touched by history operations. But although they are not added to the part rolling the part's
history stream also rolls the entities which are not in the part. This is likely the case because
the part's history stream and the default history stream are identical.

Our solution idea was to create individual history streams for the part and for the default
history stream. When we did that, when adding a created body into the part gave us an error:
"distribute entity to stream it was not created in" and the entity is not added to the part.
Although I don't understand the problem behind this error I assume I have to move the states
of creating the entitity from the default stream to the part stream, right?

What I can read from the documentation is, that there is a way to distribute states from the
default stream to a different stream. But we do not understand how this is supposed to be used
in a situation like the above?
Do the states of the creation of the body have to be moved from the default stream to the part
stream and then the body be put in the part? If yes, apparently this had to be done for each
modeling operations?
If the answer is: Switch the default history stream to the part stream where to entities under
operations are in, what happens if operations include entities from different parts?

The analysis of this brought us to the question if it is possible to have an application with
multiple parts and individual history streams per part and do modeling operations between bodies
that reside in different parts. E.g. an assembly modeling application where each assembly part
is held in individual Acis PARTs and operations (boolean, intersection) between those parts may happen.
I think I remember some texts from Spatial where this was one of the ideas behind the Acis PART.

Can you shed some ligth on this?