+
+ if (dynamics_.size () <= 1)
+ {
+ programming_error ("(de)crescendo on items with specified volume.");
+ return ;
+ }
+
+ Real delta_v = grow_dir_ * 0.1;
+
+ Real start_v = dynamics_[0]->volume_;
+ if (dynamics_.back ()->volume_ < 0)
+ dynamics_.back ()->volume_ = max (min (start_v + grow_dir_ * 0.25, 1.0), 0.1);
+
+ delta_v = dynamics_.back ()->volume_ - dynamics_[0]->volume_;
+
+ Moment start = dynamics_[0]->get_column ()->when ();
+
+ Real total_t = moment_to_real (dynamics_.back ()->get_column ()->when () - start);
+
+ for (vsize i = 1; i < dynamics_.size (); i ++)