From bb35864a550b3ff0941b06316372dd8579faff71 Mon Sep 17 00:00:00 2001
From: Ibodan <->
Date: Thu, 17 Jan 2019 06:12:18 +0900
Subject: [PATCH] fix issue that palmToThumb vector which leads bad IK results
 is computed on some models

---
 CustomAvatar/VRIK/IKSolverVR.cs    | 13 +++++++------
 CustomAvatar/VRIK/IKSolverVRArm.cs |  2 +-
 2 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/CustomAvatar/VRIK/IKSolverVR.cs b/CustomAvatar/VRIK/IKSolverVR.cs
index 8d6de43..4c641fc 100644
--- a/CustomAvatar/VRIK/IKSolverVR.cs
+++ b/CustomAvatar/VRIK/IKSolverVR.cs
@@ -50,7 +50,7 @@ public void GuessHandOrientations(VRIK.References references, bool onlyIfZero) {
 			}
 			
 			if (leftArm.palmToThumbAxis == Vector3.zero || !onlyIfZero) {
-				leftArm.palmToThumbAxis = GuessPalmToThumbAxis(references.leftHand, references.leftForearm);
+				leftArm.palmToThumbAxis = GuessPalmToThumbAxis(references.leftHand, references.leftForearm, leftArm.wristToPalmAxis);
 			}
 			
 			if (rightArm.wristToPalmAxis == Vector3.zero || !onlyIfZero) {
@@ -58,7 +58,7 @@ public void GuessHandOrientations(VRIK.References references, bool onlyIfZero) {
 			}
 			
 			if (rightArm.palmToThumbAxis == Vector3.zero || !onlyIfZero) {
-				rightArm.palmToThumbAxis = GuessPalmToThumbAxis(references.rightHand, references.rightForearm);
+				rightArm.palmToThumbAxis = GuessPalmToThumbAxis(references.rightHand, references.rightForearm, rightArm.wristToPalmAxis);
 			}
 		}
 
@@ -234,7 +234,7 @@ private Vector3 GuessWristToPalmAxis(Transform hand, Transform forearm) {
 			return axis;
 		}
 
-		private Vector3 GuessPalmToThumbAxis(Transform hand, Transform forearm) {
+		private Vector3 GuessPalmToThumbAxis(Transform hand, Transform forearm, Vector3 wristToPalmAxis) {
 			if (hand.childCount == 0) {
 				Debug.LogWarning("Hand " + hand.name + " does not have any fingers, VRIK can not guess the hand bone's orientation. Please assign 'Wrist To Palm Axis' and 'Palm To Thumb Axis' manually for both arms in VRIK settings.", hand);
 				return Vector3.zero;
@@ -251,9 +251,10 @@ private Vector3 GuessPalmToThumbAxis(Transform hand, Transform forearm) {
 				}
 			}
 
-			Vector3 handNormal = Vector3.Cross(hand.position - forearm.position, hand.GetChild(thumbIndex).position - hand.position);
-			Vector3 toThumb = Vector3.Cross(handNormal, hand.position -forearm.position);
-			Vector3 axis = AxisTools.ToVector3(AxisTools.GetAxisToDirection(hand, toThumb));
+			Vector3 wristToPalm = hand.rotation * wristToPalmAxis;
+			Vector3 handNormal = Vector3.Cross(wristToPalm, (hand.GetChild(thumbIndex).position - hand.position).normalized).normalized;
+			Vector3 toThumb = Vector3.Cross(handNormal, wristToPalm).normalized;
+			Vector3 axis = Quaternion.Inverse(hand.rotation) * toThumb;
 			if (Vector3.Dot(toThumb, hand.rotation * axis) < 0f) axis = -axis;
 			return axis;
 		}
diff --git a/CustomAvatar/VRIK/IKSolverVRArm.cs b/CustomAvatar/VRIK/IKSolverVRArm.cs
index 7f68247..2f3fa74 100644
--- a/CustomAvatar/VRIK/IKSolverVRArm.cs
+++ b/CustomAvatar/VRIK/IKSolverVRArm.cs
@@ -416,7 +416,7 @@ private Vector3 GetBendNormal(Vector3 dir) {
 				b = chestRotation * b;
 
 				b = Vector3.Slerp(b, armDir, 0.5f);
-				Vector3 vectorHand = (q * wristToPalmAxis * 0.15f + q * palmToThumbAxis * 0.85f) * -1.0f;
+				Vector3 vectorHand = q * Vector3.Slerp(wristToPalmAxis, palmToThumbAxis, 0.85f) * -1.0f;
 				float handWeight = (Vector3.Dot(b, vectorHand) + 1.0f) * 0.5f * 0.75f; // to range of 0 - 0.75
 				b = Vector3.Slerp(b, vectorHand, handWeight);