Here is a list of frequent errors we can see some new GDTF authors are making, together with description on how to eliminate these issues. By following this advice you will be creating GDTF files of much better quality.   Custom GDTF Attributes Do not define custom attributes. If you think that the attribute you are needing is not in the GDTF Builder, look more closely. In 99%, the needed attribute is already defined in GDTF and thus it allows all software utilizing GDTF to know w