Hello,
i want to use as input for the pointcloudcombiner certain files, which i have written in different attributes (neigbor_[0-7] of one feature (eg 2671_1262). These are the neighbouring tiles of lidar data. So far I have not found a way how I can pass the attributes (complete file path + filename) or a list as input to the PCCombiner. Is there an elegant way for this in FME? 
I get the impression you're not going about this in the most efficient way, it looks like you're reading a lot of LAS files, then determine which ones you need and then combine those. This potentially means you're reading a lot of data that you don't really need.
If you have the extents of the LAS files you can perform the neighbor finding like you currently do, then use a ListExploder instead of the BulkAttributeRenamer to get 1 feature per tile and then read them through a FeatureReader.
I get the impression you're not going about this in the most efficient way, it looks like you're reading a lot of LAS files, then determine which ones you need and then combine those. This potentially means you're reading a lot of data that you don't really need.
If you have the extents of the LAS files you can perform the neighbor finding like you currently do, then use a ListExploder instead of the BulkAttributeRenamer to get 1 feature per tile and then read them through a FeatureReader.
Many thanks for your quick answer. I have now rewritten the script so that It works with the ListExploder, but I am not able to process them in the FeatureReader. In the Inspector in front of the FeatureReader I see the list elements, but after processing the list in the FeatureReader and the subsequent PointCloudCombiner I only ever get the original file played. This means that the adjacent tiles are not read in and combined. 8-(