The evil autodesk uses its own way of operation and the format, according to statistics, 70% of the drawings in the world are DWG format. So everyone has to ponder this DWG. If the company said to launch his own format counter DWG, you will be a dream. After all, Lin Zi is very big. . :)
OpenDesign has been cracking in the DWG format, making the most successful one. It should be said to be the only one. This organizational three times invitation Autodesk joined them, and the results were ignored.
Of course, we use OpenDWG to resolve DWG is best. OpenDWG's early versions have ODT and ODV, new seems to be DWG DRICT, many people can display DWG directly with ODV. But this kind of demand is not much. I want to query the property? I want to measure distance? I want to be simple to edit, I have to have a complex editor after all, don't say it. ODV is of course not ... So I have to table ODT, ODT full name Opendwg Tool Kit .. It provides a function to resolve 2002 previous versions of DWG.
Some companies have thought that they bought Opendwg, which is not. ODT can help you resolve DWG files, but what is the solution that is discovered? You have mline, there is polyline, there is mtext, there is Hatch, XDATA, DIMStyle. . . ? Is there a PowerCAD in Germany not supported SPLINE?
The DWG contains model space and drawings space, don't say you don't know these two spaces. Then, record several style linked lists, font style linked lists, text style linches, size style linked lists, View Links, ViewPort Links, Frozen Links, Blocks, Tabletline Lines, Line Lines, Mline Style Links, etc .; Save the system variables in the drawings, bothering as cattle, downing the entity in the true model space. . . Different fonts and text style, we can discuss this in the future. The so-called font is .SHP.SHX font. Each text style may be used in the SHX font, or it may be a TTF font. TEXT is created and drawn to check your text style, text style and find related SHX fonts.
Six or seventy options in the dimension pattern are controlled, these options are not only the same in the influence of the size, because the size is saved, and it is faster for painting. Is it disgusting? So you must have a rebuilding mechanism to serve these guys.
The View Link list is used to record the display location.
The ViewPort link is mainly used to adjust the printing effect in the drawing space.
Frozen linked list? In DWG, some layers are hidden, and these hidden layers are rarely used, and the result is frozen. In order to improve the speed, don't read it.
The block list contains the block information, each block has its own Entity Link. Some internal blocks should pay attention. For example, "* D" is the size block. There is also model space and drawings space also managed by block mechanisms. I found that AutoCAD likes to use blocks to simplify some operations, this should be drawn.
The cross-sectional line and the linear linked list record their respective shape definitions. Strange it? The definition of cross-sectional line and line type is actually saved in the file. Yes, this benefit is that this DWG file can be opened on any other ACAD, I have my own line type definition, don't your system line style. If the line type and cross-sectional line defined by the user is more resursors. . In addition, the shape definition of the line type and section line does not account for too much space, and a few lines of Text text.
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