I am feeling much too tired this afternoon to read the court documents, in which 3D Systems is suing Formlabs and Kickstarter. I'll just link to Joseph Flaherty's story at Wired, who does a good job of explaining issue, posting the court documents, and listing informative comments.
From my quick read of the issue, it appears that 3D Systems is upset that Formlabs is producing 3D prints for a fraction of the price of other stereolithography systems. In the comments section, readers argue that the 3D Systems law suit probably is invalid, due to the way their patent is worded.
If nothing else, 3D Systems crossed over to the dark side by launching the law suit hours before sitting down at the Thanksgiving table.