Special characters in significant names (like layer name, material name, property name)

Based on          IFC2x3

Initiator            ISG Meeting-Dijon

Effects              Extended Coordination View

Date                    2006 11 24


It has to be acknowledged that existing applications have various restrictions on what are legal characters, and what is the maximum string length for certain names, e.g. for a layer name, for an object property name, for a material name, etc. These restrictions are very different and cannot be unified.

Therefore the following was agreed: There are no restrictions on export, beside not using LF, FF and other characters in a single string. Special characters, like white space "", various special characters "&", "5", "[", "(", etc. are allowed for export.

On import, each receiving application is required to parse the name string prior to assigning it. While parsing, not allowed characters have to be replaces by an underscore "_". Additional effort have to be made to avoid that two distinct names become equal by e.g. truncating it to the maximal length.

NOTE: It should be recommended to deal with this issue in BIM modeling guidelines to avoid using such names. This is however outside of this agreement and the certification requirement.

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