Thank you SOOOOO MUCH!!!!!

This tool is amazing! However, I encountered some error with the follow push/pull.
When I tried to use follow push/pull, the following error occurred:

undefined method `angle_between' for nil:NilClass

Ruby File Line Method

JointPushPullAlgo.rb 1339 vertex_average_factor
JointPushPullAlgo.rb 1089 follow_compute_direction
JointPushPullAlgo.rb 1056 block in block_prepare_vertices_F
JointPushPullAlgo.rb 1056 each
JointPushPullAlgo.rb 1056 block_prepare_vertices_F
JointPushPullAlgo.rb 890 block in block_prepare_vertices_all
JointPushPullAlgo.rb 890 each
JointPushPullAlgo.rb 890 block_prepare_vertices_all
JointPushPullAlgo.rb 500 algo_prepare_calculation_exec
JointPushPullAlgo.rb 477 algo_prepare_calculation
JointPushPullTool.rb 692 dragging_start
JointPushPullTool.rb 1190 onMouseMove
22-Feb-15 14:56:56

Does anyone know why?? I followed exactly what the video showed, push/pull the top of a cone shaped object.

Would love some help! Thank you!!