9

Importing AutoCAD Drawing Files 537
bounding box in tools like AutoCAD, the 3ds Max
viewports and transform tools do not respond
properly. When you use them, the cursor does not
move smoothly.
For example, if you have a file that is a mile wide,
but your system units are millimeters, you have a
scene width of 1.6 million units, which is too great
a value. If you change your system unit to feet, this
is less taxin g on the system.
If any side of the scene’s bounding box measures
larger than ± 1,000,000 system units, you will see
the following dia log:
Su ppor t of M ulti ple Ma ter ial s on
Imported ACIS Solids
3dsMaxsupportsmultiplematerialsperobject
in DWG files exported as ACIS solids from Revit
Architecture/Structure/MEP 2008 and later, as
well as solid primitives created in A u toCAD
Architecture 2008 (formerly ADT) and later.
Imported solids can have Multi/Sub-Object
materials (page 2–1594) that you can view and
manipulate in the Material Editor.
Note: Previous versions of 3ds Max supported
multiple materials for polymeshes but only one
material ID for each ACIS solid when impor ting
a DWG file, regardless of how many material IDs
had been assigned to the s olid.
Note: Legacy AutoCAD DWG import does not
support multiple materials on ACIS solids.
Process
When3dsMaximportsaDWGfilefromAutoCAD
or Revit Architecture (version 2008 and later)
w ith either the Layer, Blocks as Node Hierarchy,
Split by Material” or the Entity, Blocks as Node
Hierarchy derivation methods, multiple material
IDs are readable and editable as Multi/Sub-Object
materials in the Material Editor.
3dsMaxreadseachfaceofanimported
AutoCAD/Revit solid to determine if it contains
any material IDs that can be imported. If the
program reads more than one material ID from a
solid, it tr anslates each material ID on import and
re-assigns it to the object.
The program creates Multi/Sub-Objec t materials
only if it finds more than one material ID; if an
ACIS solid contains only one mater ial ID, 3ds Max
creates and assigns a standard/architectural
material instead.
Note: 3ds Max first evaluates the imported file to
find any Revit material IDs, and then looks for
AutoCAD material IDs.
Note: If you import a DWG file with the Layer,
Blocks as Node Hierarchy, Split by Materials
derivationmethod,itdoesnotsplitthesolidto
reflect its materials set.
Multi/Sub-Object Material Nam in g
In earlier versions, 3ds Max read the material
ID information fro m the color ID of the
AutoCAD/Revit material ID’s face. Now, it creates
a Multi/Sub object material for every translated
per face material ID each time you import a DWG
file that contains an AutoCAD/Revit solid.
When the program finds multiple materials
assigned to an ACIS solid and creates a
M ulti/Sub-Object material, the Multi/Sub-Object
material consists of instances of standard
architectural scene materials.
Naming Conflic ts
Material IDs are unique within one DWG file.
However,thesamematerialIDmayappearin