I'd like to build off of hand_interaction in mit_ros_pkg in order to recognize a form of sign language with the Kinect. I installed electric this morning and then checked out mit_ros_pkg/trunk . After I checked out motion_planning_common/trunk, everything compiled fine. I ran roslaunch hand_interaction finger_detector.launch and the hands (but !fingers) are detected successfully for a bit but then I get > detectskelhands: /usr/include/eigen3/Eigen/src/Core/Block.h:278: > Eigen::Block true>::Block(XprType&, typename > Eigen::internal::traits InnerPanel, true> >::Index) [with XprType = Eigen::Matrix 3>, int BlockRows = 3, int BlockCols = 1, bool InnerPanel = true]: Assertion > `(i>=0) && ( ((BlockRows==1) && (BlockCols==XprType::ColsAtCompileTime) && > i && i got hand -0.34, -0.482697, 1.026878 [handdetector-7] process has died [pid > 10192, exit code -6]. I got this with the debug compile flag and launch-prefix="xterm -e gdb" added to the .launch file I see other people have had similar errors that were attributed their pcl version. But electric has pcl 1.1 right? So is it my .launch file? Or because mit_ros_pkg isn't compatible with electric yet? Or some other reason entirely? Should I just go read up on linear algebra? Thanks in advance!