DWG Reader
DWG is the AutoCAD file format; it’s used to save CAD data in 2D and 3D. Both 2D and 3D may be present in the same file.
Please note, our DWG reader is currently only available on Windows and Linux.
A file does not need to have a particular extension to be read correctly by HOOPS Exchange; however, the file extension of DWG files that you can expect to be loaded by HOOPS Exchange is:
.DWG
.DXF
Our readers are updated to the latest released version within 90 days of the release of the authoring software. You can see the Our readers are updated to the latest released version within 90 days of the release of the authoring software. You can see the exact version supported in the current release here.
Drawings – 2D
2D drawings consist of one or several sheets. Each sheet can have blocks, tables, text, dimensions, images, OLE objects (like Excel spreadsheets), filled areas and any wireframe types (lines, arcs, polylines, etc.).
A block is a subpart of a sheet that can also contain any of the items described above.
Each item may belong to a layer and can have a line pattern, color, and line width.
Filled areas may be filled with hatches or a solid color.
Units
For 3D models, units are defined by the INSUNITS variable. There is a specific treatment for DXF file: MEASUREMENT variable is used if it is defined and if INSUNITS is not defined. In this case if MEASUREMENT is set to English (0), the unit will be set as kA3DUnitInch , and it MEASUREMENT is set to metric (1), the unit will be set as kA3DUnitMillimeter.
Sheets
Sheets are supported.
DWG files can contain several sheets. Each sheet is saved in A3DDrawingModelData.m_ppDrwSheets.
Sheets contain drawing blocks, views, and wireframes.
Wireframes are converted into polylines.
Limitation: Exchange does not support sheet sets.
### Drawing Views
There are two spaces in which a drawing can be created. These are represented by the Model and Layout tabs. Typically, a model composed of geometric objects is created in a three-dimensional space called model space. A final layout of specific views and annotations of this model is created in a two-dimensional space called paper space. After the model is created in model space, it’s then prepared for plotting in the Layout tab in paper space.
Multiple-View Drawing Layouts (paper space) are supported
Single-View Drawings – (model space) are also supported
Blocks
Each sheet can have blocks, tables, texts, dimensions, images, OLE objects (such as Excel spreadsheets), filled areas, and any wireframe type (lines, arcs, polylines, etc.). (Please note, OLE objects are not supported.)
A block is a subpart of the sheet that can also contain any of the items described above.
Each item may belong to a layer and can have a line pattern, color, and line width.
Filled areas may be filled by hatches or completely colored.
Limitation: Exchange does not support block attributes or block behaviors.
Layers
Layers are used to group data and change graphical attributes. This includes: * Colors * Line Type * Line Weight * Transparency All of these attributes are supported by HOOPS Exchange.
Layers have names and properties.
Limitation: Exchange does not support Layer properties.
Geometry
Geometry includes lines, polylines, arcs, circles, tori, ellipses, splines, helices, and construction/reference geometry. Limitations: All entities are converted to polylines. Geometry constraints are not supported.
Annotations
Hatches, Fills, and Wipeouts, Notes and Labels, Table, Dimension and Tolerance are all displayed.
3D Models
Polysolids, B-rep, and meshes are supported.
Exchange also supports trimmed/untrimmed surfaces, NURBS, and procedural surfaces.
Miscellaneous
Sections in 2D drawings are tessellated.
For materials, Exchange supports transparency and specular, ambient and diffuse color.
Xrefs are supported: If a DWG file has references to external DWG files, they will be loaded.
The following entities are not supported:
Lighting
Textures
Password-protected files and encrypted files
Embedded Data (OLE) are not supported
