What does “importing” a file actually mean? Does opening a file always imply that a file is imported?

Generally speaking, each program stores its data in its own format. This means that, besides saving data, which can generally be used, it can also save attributes specific to this data.

The same applies with Arbortext IsoDraw. Besides storing pure geometrical data, e.g. the start and end points of a line, other additional information, which is important for Arbortext IsoDraw, is also stored. This not only includes such things as the attributes of an element, e.g. pen, style or halo, but also data, which is only relevant for Arbortext IsoDraw, e.g. the depth of a thread. Since the Thread element does not exist in this form in any other program, Arbortext IsoDraw must write its own format in order to be able to recognize this element as a thread again later.

When Arbortext IsoDraw opens one of its files in the way described above, no import procedure takes place. The information contained in the file is available in the exact form required by Arbortext IsoDraw.

The situation is different when you open a file from another program, e.g. Adobe Illustrator. The same applies, of course, to this program as for Arbortext IsoDraw: It stores its data in accordance with its own structure. Adobe Illustrator does not use ellipses or threads as elements, but Bézier paths instead. Consequently, an Illustrator file only contains information about Bézier paths, which Adobe Illustrator is naturally able to read with ease.

This very simplified description should help to illustrate that Arbortext IsoDraw and Adobe Illustrator files are fundamentally different from each other. Nevertheless, if Arbortext IsoDraw can read an Illustrator file, it must be converted into Arbortext IsoDraw format: Therefore, it is imported.

Importing a file thus implies nothing more than a translation process. This process is not too dissimilar to that of translating a text into another language. Also in this case it is often not possible to convey all the details without losing some aspects of the language, e.g. idiomatic expressions. However, the translator mostly finds a way of expressing the sense of idiomatic expression using other words.

Importing illustration data functions in a similar way. Most data can be transferred completely, although there is almost always an amount left over which contains program-specific details. This data can only be translated by conveying its “sense”.

This type of translation, however, always results in some information being lost. This may mean that attributes of an object are lost during the transfer procedure. For example, a thread converted from Arbortext IsoDraw into Adobe Illustrator format can only be depicted as a group of Bézier paths. It is no longer possible to set the thread depth or diameter in Adobe Illustrator in the same way as in Arbortext IsoDraw.

The differences between the two programs become even more acute when an element cannot be converted properly. HPGL format, for example, contains no commands for displaying curves, meaning that each curve has to be converted into a series of short, straight-line segments.

The same naturally applies when a drawing is exported into another format. Arbortext IsoDraw contains a large number of elements and attributes which are not supported in other programs. In which case, you will need to choose the “least of all evils” when converting a file.

It is possible to measure the quality of a filter by how carefully the individual attributes are converted. In many instances, just the pure geometrical data is translated, but it is generally possible to do more. However, you should keep in mind: the filter is not always to blame if information is lost.