Read AutoCAD data: Read elements from AutoCAD or DXF-Files
With this command, elements can be read directly from a distinct or from multiple AutoCAD layers or from a DXF-File.
Chapter “Definition of macro elements within AutoCAD” describes which types of AutoCAD entities can be read. Only individual entities can be read, nested entities such as blocks and regions or polylines composed out of lines and arcs must be divided into individual entity’s first, using AutoCAD command “xplode”. If some entities cannot be interpreted as makro elements (e.g. only two corner nodes with a curved surface element), these entities are left out. Read elements will be appended to the prior read structure, except option "Delete old elements" is selected. After invocation of the command the following dialog box pops up. After checking and setting up the proper options the button "Read" will start reading.
The list shows all available layers currently defined within AutoCAD or contained in the DXF file. Select the layers to read entities from. One or more layers can be selected. The button „Select all“ selects all layers and the button „New“ deselects all layers. With button „Update layer list“ the available layers are new checked, this could be necessary after new AutoCAD layers have been generated or a new DXF file is selected.
The AutoCAD layers are continuously numbered and this number is stored as a layer ID with the elements.
All: All AutoCAD entities of the given layers will be read and converted to macro elements. The interpretation of the entities is discussed within chapter “Definition of macro elements within AutoCAD”.
Select graphically: Only these entities will be read, which are contained within a following selection with AutoCAD commands. Only elements from one marked layer can be selected. Pressing Return ends selections. Start the AutoCAD selection after pressing button „Read“ and after you have confirmed that you will select graphically in a pop up dialog.
Only following type: If this option is selected, an entity type (POLYLINE, LINE, CIRCLE, ARC, SOLID, 3DFACE, TRACE, POINT) must be selected in the list. In this case only entities of the given type are read from the selected layers.
If the option „DXF-File“ is marked, the title of a DXF-File must be selected in a file selection window. The layers contained in the file are shown in the layer list. You can select individual layers and entity types that should be read from the file. Button „New file“ shows a file selection window where a new file can be selected.
Delete old elements: All previously read elements will be deleted.
Append new elements: Newly read elements are appended to previously read elements.
Group ID: You can specify a group ID for the new elements. Default is the highest group ID + 1.
Mechanical type ID: You can specify a mechanical type ID for the new elements. Default is the highest type ID + 1.
T105: With this option selected, closed polylines with more than 4 corner nodes (vertices with an inner angle less than the given value) are stored as type 105 elements.
T400: With this option selected, closed polylines with more than 5 vertices are stored as type 400 elements with straight edges. If some edges should be circular, the intermediated nodes on these edges must later be marked with a – sign using command “Element definition”.
T45: With this option selected, polylines with more than 4 corner nodes (vertices with an inner angle less than the given value) are stored as type 45 elements, where only the 3 smallest corners and the first are considered as element corners.
Corner angle: Within this input field you may enter an angle value for the interpretation of polylines. All polyline vertices with inner angles lower than this value are considered as element corner nodes while remaining vertices in this case are considered as intermediate nodes on element edges. This is not applied by elements that are defined using successive polyline vertices with equal coordinates (double vertices).
Dmax/dmin: This input field may contain the ratio m. All vertices within a distance lower than dmax/m will be considered as double vertices. dmax stands for the maximum distance between 2 vertices.
Eps: After reading from AutoCAD all nodes with distance lower than this value (eps) will be merged into a single node. If no value > 0 is given, the value of eps will be set automatically in relation to the smallest edge length of all elements. Providing a value for eps would be useful to prevent merging of closely related nodes.
Element type: For polygon meshes it is possible to generate elements of type 40, 42 and 45. Default is saving each mesh as an individual 4-node element. With element type 42 2*2 neighbored meshes are saved as an element with one intermediate node on the edges. For element type 45 4*4 meshes are converted as an element with 3 intermediate nodes on the edges.
Number: Within this field it is possible to specify the number of elements to be generated for x and y direction. This means that not all edges of the polygon mesh will be used for element generation. If, for example, the polygon mesh consists of 128 segments in one direction and only every second edge should be used for generating type 45 elements, the number should be given as 16.