DWG to Feature Class Mapping ==> Feature Class, quotes:
"You can map more than one drawing object to a single feature class."
This can be very tricky.
Lets say you have drawing object/entities categorised as A and B (either based on layer, or on Object data, or on Object Classification) and want to map them to the same SINGLE TARGET FEATURE CLASS.
In this case you need to be sure that you have for A and B the same Target attributes mapped. If not, the attributes may end up in the wrong feature class properties or even you will loose some of the info if there is a different datatype involved.
Here is an simplified example:
DRAWING ENTITIES category A => Feature Class C
DRAWING ENTITIES category B => Feature Class C
Feature Class C properties:
Mapping A to C (setting following attributes to properties mapping)
.layer => NAME
.length => LENGTH
Mapping B to C (setting following attributes to properties mapping)
.layer => NAME
ODWNER => OWNER
(Object data exmaple)
What will happen is that for the first catagory that MAP 3D selects to be exported the target properties are used. (let assume here A: NAME, LENGTH.
When category B is processed it turns out that it will not respect the target properties from B but MAP 3D will use those of the first mapping. This results in OD.OWNER ending up in LENGTH (if the datatype allows so) or set to null or 0 if the datatypes do not match.
It seems MAP 3D is using the "same single sql type statement for C" for both catagories A and B and populating the attributes just in sequence, while it should use different statements for those 2 catageories even though there going into the same target class.
Those exporting entities to FDO/rather file or DB, be ware as there are in general a lot off issues while exporting one way or the other!