DXF: Difference between revisions
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Shapes within a layer can be subtracted from each other, without the requirement of hatching the shape. For example, multiple line rings are drawn within each other. By subtracting these correctly, multi-polygons can be created with the expected inside and outside. | Shapes within a layer can be subtracted from each other, without the requirement of hatching the shape. For example, multiple line rings are drawn within each other. By subtracting these correctly, multi-polygons can be created with the expected inside and outside. | ||
[[File:DXF_subtracting_shapes.png]] | [[File:DXF_subtracting_shapes.png|thumb|right|200px]] | ||
==Colors== | ==Colors== | ||
Revision as of 12:49, 28 November 2022
DXF is a file format to exchange CAD data from Autodesk. It is the "open" equivalent of DWG files.
DXF file data
A DXF file is subdivided in several sections. The sections in this file that we inspect are:
- HEADER: contains location and scaling information
- GEODATA: contains geo-location information
- TABLES: containing definitions of layers
- ENTITIES: containing 2 and 3 dimensional shapes
- BLOCKS: containing 2 and 3 dimension shapes, reusable using INSERTS in ENTITIES.
Entities
Currently, the following Autodesk CAD entity types are supported:
- LWPOLYLINES (2 dimensional line strings), including bulges.[1]
- LINE (single lines).[2]
- POLYLINE (3 dimensional line strings), currently only interpreted as 2 dimensional. The z-coordinate is ignored.[3]
- HATCH (polygonal data constructed using other boundary entities).[4]
- CIRCLE: full and partial circles, given a center point, radius and start and end angle.[5]
- ELLIPSE: full and partial ellipses, given a center point, major and minor axis, rotation and start and end angle.[6]
- ARC: curved lines given a center point and a radius.[7]
- VERTEX: 2 dimensional point.[8]
- POINT: Same as vertex, but 3 dimensional. Currently only interpreted as 2 dimensional. The z-coordinate is ignored.[9]
- SPLINE: 2 dimensional Control point splines are currently supported.[10] Fit point splines are currently not supported.
- INSERT: Predefined BLOCKS inserted at a point and with a rotation and a scale.[11]
Blocks
Blocks (BLOCKS) are parts in a CAD drawing that can be reused multiple times by inserting them at different locations with optional alternative rotations and scales. The usage of blocks in a DXF is supported.[12]
Blocks can consist of shapes similar as to those definable in entities, including the insertion (INSERT) of other blocks. Each of these shapes can belong to a different layer. BLOCKS can also have attribute defined (ATTDEF) for them. These attributes can contain any string value.
Each block is converted to one or more unique feature(s). Features within a block are kept separate when they belong to different layers.
Layers
In the DXF file, entities are always assigned to one particular layer. In AutoCAD, layers can be turned on and off. This visibility does not influence whether or not the entities in this layer can be imported.
Shapes within a layer can be subtracted from each other, without the requirement of hatching the shape. For example, multiple line rings are drawn within each other. By subtracting these correctly, multi-polygons can be created with the expected inside and outside.
Colors
Colors are stored by index[13].
Notes
- Fit point splines are currently not supported.
How-to's
References
- ↑ LWPOLYLINES ∙ Found at: https://knowledge.autodesk.com/support/autocad/learn-explore/caas/CloudHelp/cloudhelp/2022/ENU/AutoCAD-Core/files/GUID-392BF13C-D9E7-47A8-8E07-435296332279-htm.html ∙ (last visited: 26-9-2022)
- ↑ LINE ∙ Found at: https://knowledge.autodesk.com/support/autocad/learn-explore/caas/CloudHelp/cloudhelp/2022/ENU/AutoCAD-Core/files/GUID-DB0FA734-8F5C-4000-92FF-89BA2D42CA21-htm.html ∙ (last visited: 26-9-2022)
- ↑ POLYLINE ∙ Found at: https://knowledge.autodesk.com/support/autocad/learn-explore/caas/CloudHelp/cloudhelp/2022/ENU/AutoCAD-Core/files/GUID-392BF13C-D9E7-47A8-8E07-435296332279-htm.html ∙ (last visited: 26-9-2022)
- ↑ HATCH ∙ Found at: https://knowledge.autodesk.com/support/autocad/learn-explore/caas/CloudHelp/cloudhelp/2023/ENU/AutoCAD-Core/files/GUID-27C104F2-B687-4025-B50B-A58E37329832-htm.html?us_oa=akn-us&us_si=8126699c-9f97-4fa3-9b23-fa556e058edb&us_st=Hatch ∙ (last visited: 26-9-2022)
- ↑ CIRCLE ∙ Found at: https://knowledge.autodesk.com/support/autocad/learn-explore/caas/CloudHelp/cloudhelp/2022/ENU/AutoCAD-Core/files/GUID-EDC69C38-6651-46DA-AFCC-56F2EB0A6AC6-htm.html ∙ (last visited: 26-9-2022)
- ↑ ELLIPSE ∙ Found at: https://knowledge.autodesk.com/support/autocad/learn-explore/caas/CloudHelp/cloudhelp/2022/ENU/AutoCAD-Core/files/GUID-2461D382-B7E5-44B3-A34C-735CE0089C8D-htm.html ∙ (last visited: 26-9-2022)
- ↑ ARC ∙ Found at: https://knowledge.autodesk.com/support/autocad/learn-explore/caas/CloudHelp/cloudhelp/2022/ENU/AutoCAD-Core/files/GUID-C78378FD-4704-4D0A-9D86-82FCBB118097-htm.html ∙ (last visited: 26-9-2022)
- ↑ VERTEX ∙ Found at: https://knowledge.autodesk.com/support/autocad/learn-explore/caas/CloudHelp/cloudhelp/2023/ENU/AutoCAD-Core/files/GUID-84591B48-71B9-4258-B287-CD2391C946D2-htm.html ∙ (last visited: 26-9-2022)
- ↑ POINT ∙ Found at: https://knowledge.autodesk.com/support/autocad/learn-explore/caas/CloudHelp/cloudhelp/2023/ENU/AutoCAD-Core/files/GUID-3F5861A1-9A63-42A6-8F12-3395771BAA6D-htm.html?us_oa=akn-us&us_si=cd548ae9-dde6-4a75-bb71-c74923034ef2&us_st=Point ∙ (last visited: 26-9-2022)
- ↑ SPLINE ∙ Found at: https://knowledge.autodesk.com/support/autocad/learn-explore/caas/CloudHelp/cloudhelp/2023/ENU/AutoCAD-Core/files/GUID-58316136-30EB-499C-ACAD-31D0C653B2B2-htm.html ∙ (last visited: 26-9-2022)
- ↑ INSERT ∙ Found at: https://knowledge.autodesk.com/support/autocad/learn-explore/caas/CloudHelp/cloudhelp/2023/ENU/AutoCAD-Core/files/GUID-BC0FD3C1-3BFC-4C5D-AB9A-BF480D5084BE-htm.html ∙ (last visited: 26-9-2022)
- ↑ BLOCKS ∙ Found at: https://knowledge.autodesk.com/support/autocad/learn-explore/caas/CloudHelp/cloudhelp/2023/ENU/AutoCAD-Core/files/GUID-7410E7FB-3E0D-4411-B8F6-DBD59C71E87D-htm.html ∙ (last visited: 26-9-2022)
- ↑ AutoCAD Color Index (ACI) RGB equivalents ∙ Found at: https://gohtx.com/acadcolors.php ∙ (last visited: 26-9-2022)