What are you going to use the descriptor for? I'm mostly familiar with descriptors useful as features for keypoints for cloud to cloud registration. Here are links I found useful when I was playing with PCL registration algorithms:
- http://www.di.ubi.pt/~lfbaa/pubs/iros2012.pdf
- http://www-oldurls.inf.ethz.ch/personal/zeislb/publications/aldoma_2012jram_PCLTutorial.pdf
- presentations in http://www.pointclouds.org/media/ especially those in links on top of the page: RSS2011 IROS2011 ICCV2011 ICRA2012 CRV2012 CVPR2012 IROS2012 ICRA2013 CGLIBS13
- PCL code
- google :-)