[Bf-blender-cvs] [1b32ac9] alembic: Disabled the goal spring that is supposed to stabilize roots.

[Lukas Tönne]

Commit: 1b32ac9779c709918c3bf9d46e9e4bb1892dd8bc
Author: Lukas Tönne
Date:   Mon May 11 19:46:41 2015 +0200
Branches: alembic
https://developer.blender.org/rB1b32ac9779c709918c3bf9d46e9e4bb1892dd8bc

Disabled the goal spring that is supposed to stabilize roots.

There are larger bugs still roaming free which need to be solved first.
Goal springs also are inherently unstable because the solver can not
properly estimate their Jacobian.

===================================================================

M	source/blender/physics/intern/BPH_mass_spring.cpp

===================================================================

diff --git a/source/blender/physics/intern/BPH_mass_spring.cpp b/source/blender/physics/intern/BPH_mass_spring.cpp
index ce5585e..5b49314 100644
--- a/source/blender/physics/intern/BPH_mass_spring.cpp
+++ b/source/blender/physics/intern/BPH_mass_spring.cpp
@@ -1310,6 +1310,7 @@ static void strands_calc_curve_bending_forces(Strands *strands, float space[4][4
 //		mul_m3_m3m3(Mstate, rot, Mrest);
 	}
 	
+#if 0
 	{ /* apply force */
 		/* Note: applying forces to the first segment is necessary to equalize forces on the root,
 		 * otherwise energy gets introduced at the root and can destabilize the simulation.
@@ -1331,6 +1332,7 @@ static void strands_calc_curve_bending_forces(Strands *strands, float space[4][4
 		BPH_mass_spring_get_velocity(data, vroot, rootvel);
 		BPH_mass_spring_force_spring_goal(data, vj, goal, rootvel, stiffness, damping, NULL, NULL, NULL);
 	}
+#endif
 	
 	do {
 		float restlen = len_v3v3(it_bend.vertex1->co, it_bend.vertex0->co);