AutoCAD Drawing Object

Use

You can import and view AutoCAD Drawing Object (.dwg) files. You can also save files to this format.

AutoCAD Drawing Object is a binary format only and is the principle data exchange format used by AutoCAD. It contains a complete description of the AutoCAD drawing, including the model and layouts, viewports and layers. A .dwg file contains a number of entities representing the model geometry such as curves, lines, solids, polygons, and blocks that form a model hierarchy. All this information is read from the file and used to construct a scene that matches the original drawing as closely as possible.

Supported

Layouts imported as portfolios
- Each layout contains at least one model view - the master view
- Empty paper-space layouts are ignored
Named views, for both model- and paper-space layouts, imported as extra model views in the layout portfolio
Block hierarchy imported as nodes
Block attributes imported as node metadata
Drawing attributes imported as scene metadata
Layers can be seen in the Layers panel
- Frozen layers are ignored
Cameras
XRefs
Parts data
2D and 3D entities and geometry
- Geometry representation of entities read as meshes or 3D polylines
- Solids imported as meshes
- Dimensions and leaders imported as 3D polylines
- Text imported as either native text primitives or geometry. If text is imported as geometry, type (mesh or 3D polyline) depends on the type of the font being used.
Colors and materials
- Entities can use indexed or true color
- Entities can have materials assigned with various attributes such as specular highlight, reflection, and opacity
- Materials can be either attached to entities or attached to layers. For example, if a material called WOOD is attached to entity A, entity A has the WOOD material. Or, if the WOOD material is attached to Layer 1, all the entities under Layer 1 have that WOOD material.

Limitations

Animation
BoM support based on part names
Configurations
NURBS and Solids
Tessellation control
Textures
UV coordinates

Features

This format contains both import and export options. You can use them to customize the way in which your file is opened and saved.

Import Interface

Field	Functional Description
General	Defines the common settings Import Layouts: Defines the layouts to import All: Imports all layouts (both model- and paper-space), and makes the last used one active Active Only: Imports last used layout only Model Only: Imports only the model-space layout (Model) Paper Only: Imports only the paper-space layouts Specified Only: Imports only the layouts specified in the Layout Name Filter field Layout Name Filter: Defines a list of layouts to include during import. List items are separated by commas. Note This field is only available when Import Layouts is set to `Specified Only`. Import Named Views: Imports named views defined in any of the layouts in addition to the master view of the layout. Import Layers: Defines the layers to import All: Imports all layers Visible Only: Imports only the visible layers in each layout Note Entities on invisible layers are not available using this option. Specified Only: Imports only the layers specified in the Layer Name Filter field Unspecified Only: Imports all the layers except the ones specified in the Layer Name Filter field Layer Name Filter: Defines a list of layers to include or exclude during import. List items are separated by commas. Note This field is only available when Import Layers is set to `Specified Only` or `Unpecified Only`. Import Metadata: Defines the attributes to import None: No attribute is imported All: All attributes are imported Specified Only: Imports only attributes with the tags specified in the Metadata Name Filter field Metadata Name Filter: Defines a list of attributes with the specified tags to include during import. List items are separated by whitespaces. Import Text As: Determines the way in which text is imported Automatic: Conversion provides best quality depending on type of font. For more information, see Font Conversion Rules. Geometry: Imports text either as polyline or polygon mesh, depending on the type of the font. This option increases import time and memory usage. Note This option does not allow editing of imported text. Character Primitives: Imports text as native text primitives Import Line Patterns As: Determines the way in which noncontinuous lines are imported Line Material: Attempts to load lines with simple styles; for example, dashed, as polylines with the style attributes stored in their associated material. Lines with complex styles are imported as geometry. Note This option is less accurate but assists in reducing memory usage and import time. Geometry: Imports all lines as polylines without storing style attributes. This setting includes lines with simple styles in addition to the more complex styles. Note This option more accurately represents the original data, however, it increases memory usage and import time. Allow Font Substitution: If enabled, missing SHX fonts are substituted with matching TrueType fonts. Font substitution reduces overall CGM file size, but in some cases, substitution may not be an exact match. Collapse Objects: Groups similar objects together based on their type and associated layer Note This option can simplify the model hierarchy as well as reducing memory usage, but may increase import time. In addition, the individual members of a group cannot be edited separately. Normalize Scene: Scales small objects to reduce the display of geometric artifacts and minimize floating point errors. Normalizing is helpful when a model is tiny or huge, or when the polygon reduction process is slow. Use Geometry Primitives: If this option is set to Yes, the fields Import Line Patterns and Geometry Import Preference are disabled and Import Line Patterns is by default, Prefer Line Material. Geometry Import Preference defaults to As Saved.
Model Layout	Determines the way in which objects are imported and displayed in a model-space layout Geometry Import Preference: Determines the way in which the geometry of solid or surface mesh objects is displayed in model-space layouts. Note that this option does not affect the way in which wireframe geometry is displayed. As Saved: Uses the original display style Prefer Outlines: Displays objects with their outline only Prefer Solids: Displays objects as solids or surfaces Prefer Solids with Outlines: Displays objects as solids or surfaces with their outlines highlighted Initial Zoom: Sets how the model is initially displayed after import As Saved: Uses original camera position and zoom factor To Model Extents: Positions the model to the middle of the viewport and zooms the current model to its extents in the viewport so that it fully fills it Fit to Page: Positions the model to the middle of the viewport and zooms to fit the page Background Color Preference: Uses a different color palette for displaying entities with indexed colors, depending on whether the background is dark or light Note This option is available only for entities that use indexed colors, and does not affect entities with true colors. These entities always retain their color regardless of the color of the background. Prefer Dark: Displays the model with a dark (black) background and light foreground colors Prefer Light: Displays the model with a light (white) background and dark foreground colors Use Custom: Displays the model with a user-defined background color. The color of foreground entities depends on the shade of the background color Custom Background Color: Sets a user-defined background color. This option only functions if the option Use Custom is effective
Paper Layouts	Determines the way in which objects are imported and displayed in paper-space layouts Geometry Import Preference: Determines the way in which the geometry of solid or surface mesh objects is displayed in paper-space layouts. Note that this option does not affect the way in which wireframe geometry is displayed. As Saved: Uses the original display style Prefer Outlines: Displays objects with their outline only Prefer Solids: Displays objects as solids or surfaces Prefer Solids with Outlines: Displays objects as solids or surfaces with their outlines highlighted
Geometry Transformation	Transforms (rotate, position, and scale) the scene along the X, Y, and Z axes: Rotation: Sets the degrees of rotation around each axis from 0 degrees to 360 degrees. The rotation values can be entered with up to 6 decimal places. Scale: Scales the object along the X, Y, and Z axes Position: Sets the position of the scene along the X, Y, and Z axes
Floor Plan Conversion	Defines the settings for floor plan conversion Enable Floor Plan Conversion: If this information is present in the file, Floor Plan Conversion converts rooms, on the active (last used) layout into hotspots. Room attributes are assigned as hotspot metadata. If set to `Yes`, Floor Plan Conversion is enabled. Note The following fields are available only if Floor Plan Conversion is enabled. The Room Outline Layers field is mandatory, and the others are optional. If none of the named layers (optional or mandatory) exists in the file, loading stops with an error. Caution Floor Plan Conversion only converts rooms on the active layout, so you must ensure that the active layout is not excluded during import. For more information, see Import Layouts. As a best practice, for the Floor Plan Conversion workflow, set Import Layouts to `Active Only` to ensure that the active layout is loaded and other layouts are excluded. If the active layout is filtered out, loading stops with an error. Room Outline Layers: Defines a list of layers from which to collect room outlines. List items are separated by commas. Note This field is required if Floor Plan Conversion is enabled. Note Layer filter settings defined for regular drawing layers in the Import Layers option are not applicable to room outline layers defined in this field. Room outline layers are always imported regardless of any filtering, provided that they are present in the input file. Defined but missing layers are ignored. Room outline layers are also imported even when marked as frozen in the drawing. Load Room Attributes from: Defines from where to load room attributes. If set to `Specified Layers`, room attributes are loaded from the layers specified in the following field. Otherwise room attributes are collected from the same room drawing block or AEC space object that defines the room outline. Room Attribute Layers: Defines a list of layers from which to collect room attributes. List items are separated by commas. Note This field is only available when Load Room Attributes from is set to `Specified Layers`. Note This field is used only when room outlines and their corresponding attributes are defined on separate layers in the drawing. The field is not used when: the drawing is an architectural drawing and rooms are defined as AEC space objects the same drawing blocks contain both the outlines and the attributes for the rooms Display Room Attributes: Imports and displays room attributes additionally as text. Note By default, room attributes are imported as hotspot metadata only and prevented from being imported as text to reduce memory usage and import time. Title Block Layer: Defines the optional layer from which to collect title block information. Attributes from the title block are imported as scene metadata. Room Area Unit: Controls the unit in which the room area for hotspots is calculated. The calculated room area and the room area unit are stored as metadata, with the keys VE_AREA and VE_AREA_UNIT respectively, for each converted hotspot. As Saved: If the file is an architectural drawing, uses the area unit set up in the drawing. Otherwise, calculates room area unit automatically derived from the drawing unit. If the derived area unit is not any of the following units, the best matching area unit is used, honoring metric or imperial settings. Square meters [sq m]: Calculates room area in square meters. Square feet [sq ft]: Calculates room area in square feet. Square millimeters [sq mm]: Calculates room area in square millimeters. Square centimeters [sq cm]: Calculates room area in square centimeters. Square decimeters [sq dm]: Calculates room area in square decimeters. Square kilometers [sq km]: Calculates room area in square kilometers. Square inches [sq in]: Calculates room area in square inches. Square yards [sq yd]: Calculates room area in square yards. Square miles [sq mi]: Calculates room area in square miles. Ares [a]: Calculates room area in ares. Hectares [ha]: Calculates room area in hectares. Acres [acre]: Calculates room area in acres.

Export Interface

Field	Functional Description
Output Version	Establishes the version of AutoCAD in which to export the file

SHX Font Conversion Rules for AutoCAD Drawings

If SHX fonts are found on the local machine, the following conversion rules are applied:

If all the characters found in SHX font, use specified SHX font and vectorize to polylines
If there are missing characters in local SHX font, use the following rules:
- If font substitution is disallowed (default), use specified SHX font and vectorize to polylines. Note that there are surrogate characters.
- If font substitution is allowed, use fallback TrueType font and create text primitive

If SHX fonts are not found on the local machine, the system uses the corresponding TrueType font and the following conversion rules are applied:

If corresponding TrueType font found, use corresponding TrueType font and create text primitive
If corresponding TrueType font not found, use SHX fallback font and vectorize to polylines. Note that there may be surrogate chars.

TrueType Font Conversion Rules for AutoCAD Drawings

If an AutoCAD drawing contains a TrueType font, use the specified TrueType font and create a text primitive.