I am new to fme. I have a citygml file of buildings with attribute codes such as 2100, 3400. The definition of this code is in another XML file so how do I setup the workbench so that the citygml file can access the attribute values from the XML f

Use the FeatureMerger transformer to merge the attribute values from XML to your citygml data.

Use the buildings codes from citygml as a requestor and the attribute that contains those codes in xml as a supplier.

Hi @dennis​ ,

an alternative way to the one suggested by caracadrian could be use a FeatureJoiner (which performs faster on simple attribute based joins). If you want to lear more on Joins, see this article.

Hope that helps!