Fix #27891: IK stretch gives inaccurate results. Tweaked translation segment

convergence weight a bit to match angles better at typical scales.

3 files changed, 13 insertions, 9 deletions

diff --git a/intern/iksolver/intern/IK_QJacobian.cpp b/intern/iksolver/intern/IK_QJacobian.cpp
index 6cc73e9c808..5a216309cee 100644
--- a/intern/iksolver/intern/IK_QJacobian.cpp
+++ b/intern/iksolver/intern/IK_QJacobian.cpp
@@ -59,6 +59,7 @@ void IK_QJacobian::ArmMatrices(int dof, int task_size)
 
 	m_d_theta.newsize(dof);
 	m_d_theta_tmp.newsize(dof);
+	m_d_norm_weight.newsize(dof);
 
 	m_norm.newsize(dof);
 	m_norm = 0.0;
@@ -111,11 +112,13 @@ void IK_QJacobian::SetBetas(int id, int, const MT_Vector3& v)
 	m_beta[id+2] = v.z();
 }
 
-void IK_QJacobian::SetDerivatives(int id, int dof_id, const MT_Vector3& v)
+void IK_QJacobian::SetDerivatives(int id, int dof_id, const MT_Vector3& v, MT_Scalar norm_weight)
 {
 	m_jacobian[id][dof_id] = v.x()*m_weight_sqrt[dof_id];
 	m_jacobian[id+1][dof_id] = v.y()*m_weight_sqrt[dof_id];
 	m_jacobian[id+2][dof_id] = v.z()*m_weight_sqrt[dof_id];
+
+	m_d_norm_weight[dof_id] = norm_weight;
 }
 
 void IK_QJacobian::Invert()
@@ -429,7 +432,7 @@ MT_Scalar IK_QJacobian::AngleUpdateNorm() const
 	MT_Scalar mx = 0.0, dtheta_abs;
 
 	for (i = 0; i < m_d_theta.size(); i++) {
-		dtheta_abs = MT_abs(m_d_theta[i]);
+		dtheta_abs = MT_abs(m_d_theta[i]*m_d_norm_weight[i]);
 		if (dtheta_abs > mx)
 			mx = dtheta_abs;
 	}
diff --git a/intern/iksolver/intern/IK_QJacobian.h b/intern/iksolver/intern/IK_QJacobian.h
index 438b9a02c67..ecfaee5ff97 100644
--- a/intern/iksolver/intern/IK_QJacobian.h
+++ b/intern/iksolver/intern/IK_QJacobian.h
@@ -56,7 +56,7 @@ public:
 
 	// Iteratively called
 	void SetBetas(int id, int size, const MT_Vector3& v);
-	void SetDerivatives(int id, int dof_id, const MT_Vector3& v);
+	void SetDerivatives(int id, int dof_id, const MT_Vector3& v, MT_Scalar norm_weight);
 
 	void Invert();
 
@@ -89,6 +89,7 @@ private:
 
 	/// the vector of computed angle changes
 	TVector m_d_theta;
+	TVector m_d_norm_weight;
 
 	/// space required for SVD computation
 
diff --git a/intern/iksolver/intern/IK_QTask.cpp b/intern/iksolver/intern/IK_QTask.cpp
index 32ecb833899..32143518533 100644
--- a/intern/iksolver/intern/IK_QTask.cpp
+++ b/intern/iksolver/intern/IK_QTask.cpp
@@ -95,10 +95,10 @@ void IK_QPositionTask::ComputeJacobian(IK_QJacobian& jacobian)
 			MT_Vector3 axis = seg->Axis(i)*m_weight;
 
 			if (seg->Translational())
-				jacobian.SetDerivatives(m_id, seg->DoFId()+i, axis);
+				jacobian.SetDerivatives(m_id, seg->DoFId()+i, axis, 1e2);
 			else {
 				MT_Vector3 pa = p.cross(axis);
-				jacobian.SetDerivatives(m_id, seg->DoFId()+i, pa);
+				jacobian.SetDerivatives(m_id, seg->DoFId()+i, pa, 1e0);
 			}
 		}
 	}
@@ -147,10 +147,10 @@ void IK_QOrientationTask::ComputeJacobian(IK_QJacobian& jacobian)
 		for (i = 0; i < seg->NumberOfDoF(); i++) {
 
 			if (seg->Translational())
-				jacobian.SetDerivatives(m_id, seg->DoFId()+i, MT_Vector3(0, 0, 0));
+				jacobian.SetDerivatives(m_id, seg->DoFId()+i, MT_Vector3(0, 0, 0), 1e2);
 			else {
 				MT_Vector3 axis = seg->Axis(i)*m_weight;
-				jacobian.SetDerivatives(m_id, seg->DoFId()+i, axis);
+				jacobian.SetDerivatives(m_id, seg->DoFId()+i, axis, 1e0);
 			}
 		}
 }
@@ -202,10 +202,10 @@ void IK_QCenterOfMassTask::JacobianSegment(IK_QJacobian& jacobian, MT_Vector3& c
 		axis *= /*segment->Mass()**/m_total_mass_inv;
 		
 		if (segment->Translational())
-			jacobian.SetDerivatives(m_id, segment->DoFId()+i, axis);
+			jacobian.SetDerivatives(m_id, segment->DoFId()+i, axis, 1e2);
 		else {
 			MT_Vector3 pa = axis.cross(p);
-			jacobian.SetDerivatives(m_id, segment->DoFId()+i, pa);
+			jacobian.SetDerivatives(m_id, segment->DoFId()+i, pa, 1e0);
 		}
 	}