Jan Walter Schliep
The video has been recorded several years ago, still it might be useful to some of you.
This tutorial will show you how to create a clump of grass with Xfrog 3.5. You can download the tutorial files from here: wallis-eck.de/2013/wp-content/uploads/2009/02/Grass_tutorial_files.zip
And I also created a PDF describing some other possibilities: