The Drawing Interchange Format (.dxf) is a standard file format used to transfer graphical information between a variety of different software packages. It is commonly used in drafting and solid modeling programs. AeroFoil has a limited capability to import airfoils from .dxf files.
After selection of a .dxf file, AeroFoil will examine the file for drawing entities that are formatted in either the Continuous Polyline, 2dPolyline, or Line formats. If any are found, the data is scaled to a maximum x/c of 1.0 and rotated into the x/y plane. The drawing entity must begin at the airfoil trailing edge, continue along the surface, and terminate at the trailing edge. Checks are made on the data to determine if it is a possible airfoil. The entity must conform to the basic airfoil shape as given above and it must exist in one geographic plane. Three-dimensional entities are not considered valid and will be rejected. The entity may have a maximum of 250 coordinate points.
The file may contain multiple airfoils in the Polyline or 2dPolyline formats and each valid example will be displayed in sequence. Because of the limited capability of AeroFoil to process .dxf files, it is suggested that any non-airfoil information be removed from the drawing file before importing the coordinates. Any file that contains multiple examples of airfoils (or any other drawing object) in the Line format will be rejected.
Before attempting to import in the .dxf format, it is best to remove all drawing entities except for the desired airfoil.
After the data file has been read it will be shown graphically on the main display. The coordinate data is shown in a grid table that has limited editing capability. Use the mouse and/or arrow keys to navigate in the table. The selected coordinate pair will be denoted on the airfoil by a red circle. It is NOT possible to create a data file using this table.
It is not possible to test all drawing entities from all drawing programs. If you, as a user of AeroFoil, have a .dxf file which contains a valid airfoil drawing and you would like to be able to import it into AeroFoil, contact DonReid@AeroFoilEngineering.com If the drawing format is valid and you are the first to submit it, I will incorporate it into AeroFoil and you will receive a free program upgrade.
Small Print Warning: In this case, valid means that it is able to be read by the most recent version of Informative Graphics (http://www.infograph.com) free dwg viewer. Certain other sources of airfoil coordinate data that are presented as being in the .dxf format do not conform to the AutoCad conventions. These will NOT be implemented in AeroFoil. Most notably, the .dxf file must be in a standard ACSII format and the drawing entity must be a 2-dimensional airfoil.