Fix LookAtModifier3D / AimModifier3D forward vector

TokageItLab · TokageItLab · commit 381ad1e4b549 · 2026-02-02T22:38:47.000+09:00
diff --git a/doc/classes/LookAtModifier3D.xml b/doc/classes/LookAtModifier3D.xml
@@ -91,8 +91,9 @@
 		<member name="primary_rotation_axis" type="int" setter="set_primary_rotation_axis" getter="get_primary_rotation_axis" enum="Vector3.Axis" default="1">
 			The axis of the first rotation. This [SkeletonModifier3D] works by compositing the rotation by Euler angles to prevent to rotate the [member forward_axis].
 		</member>
-		<member name="relative" type="bool" setter="set_relative" getter="is_relative" default="true">
+		<member name="relative" type="bool" setter="set_relative" getter="is_relative" default="false">
 			The relative option. If [code]true[/code], the rotation is applied relative to the pose. If [code]false[/code], the rotation is applied relative to the rest. It means to replace the current pose with the [LookAtModifier3D]'s result.
+			[b]Note:[/b] This option affects the base angle for [member use_angle_limitation] unlike [IterateIK3D]'s [JointLimitation3D]. Since the [LookAtModifier3D] relies strongly on Euler rotation, the axis that determines the limitation and the actual rotation are strongly tied together.
 		</member>
 		<member name="secondary_damp_threshold" type="float" setter="set_secondary_damp_threshold" getter="get_secondary_damp_threshold">
 			The threshold to start damping for [member secondary_limit_angle].
@@ -124,7 +125,7 @@
 		</member>
 		<member name="use_angle_limitation" type="bool" setter="set_use_angle_limitation" getter="is_using_angle_limitation" default="false">
 			If [code]true[/code], limits the amount of rotation. For example, this helps to prevent a character's neck from rotating 360 degrees.
-			[b]Note:[/b] As with [AnimationTree] blending, interpolation is provided that favors [method Skeleton3D.get_bone_rest]. This means that interpolation does not select the shortest path in some cases.
+			[b]Note:[/b] As with [AnimationTree] blending, interpolation is provided that favors [method Skeleton3D.get_bone_rest] or [method Skeleton3D.get_bone_pose] depends on the [member relative] option. This means that interpolation does not select the shortest path in some cases.
 			[b]Note:[/b] Some values for [member transition_type] (such as [constant Tween.TRANS_BACK], [constant Tween.TRANS_ELASTIC], and [constant Tween.TRANS_SPRING]) may exceed the limitations. If interpolation occurs while overshooting the limitations, the result might not respect the bone rest.
 		</member>
 		<member name="use_secondary_rotation" type="bool" setter="set_use_secondary_rotation" getter="is_using_secondary_rotation" default="true">
diff --git a/scene/3d/aim_modifier_3d.cpp b/scene/3d/aim_modifier_3d.cpp
@@ -204,8 +204,9 @@ void AimModifier3D::_process_constraint_by_node(int p_index, Skeleton3D *p_skele
 	if (!nd) {
 		return;
 	}
-	Vector3 reference_origin = nd->get_global_transform_interpolated().origin - p_skeleton->get_global_transform_interpolated().origin;
-	_process_aim(p_index, p_skeleton, p_apply_bone, reference_origin, p_amount);
+	Transform3D skel_tr = p_skeleton->get_global_transform_interpolated();
+	Vector3 reference_origin = nd->get_global_transform_interpolated().origin - skel_tr.origin;
+	_process_aim(p_index, p_skeleton, p_apply_bone, skel_tr.basis.get_rotation_quaternion().xform_inv(reference_origin), p_amount);
 }
 
 void AimModifier3D::_process_aim(int p_index, Skeleton3D *p_skeleton, int p_apply_bone, Vector3 p_target, float p_amount) {
diff --git a/scene/3d/look_at_modifier_3d.cpp b/scene/3d/look_at_modifier_3d.cpp
@@ -559,6 +559,7 @@ void LookAtModifier3D::_process_modification(double p_delta) {
 			forward_vector = Vector3(0, 0, 0); // The zero-vector to be used for checking in the line immediately below to avoid animation glitch.
 		} else {
 			destination = look_at_with_axes(bone_rest).basis.get_rotation_quaternion();
+			forward_vector = bone_rest.basis.xform_inv(forward_vector_nrm); // Forward vector in the "current" bone rest.
 		}
 	}
 
@@ -574,18 +575,17 @@ void LookAtModifier3D::_process_modification(double p_delta) {
 		init_transition();
 	} else if (is_flippable && std::signbit(prev_forward_vector[secondary_rotation_axis]) != std::signbit(forward_vector[secondary_rotation_axis])) {
 		// Flipping by angle_limitation can be detected by sign of secondary rotation axes during forward_vector is rotated more than 90 degree from forward_axis (means dot production is negative).
-		Vector3 prev_forward_vector_nrm = forward_vector.normalized();
 		Vector3 rest_forward_vector = get_vector_from_bone_axis(forward_axis);
 		if (symmetry_limitation) {
 			if ((is_not_max_influence || !Math::is_equal_approx(primary_limit_angle, (float)Math::TAU)) &&
-					prev_forward_vector_nrm.dot(rest_forward_vector) < 0 &&
-					forward_vector_nrm.dot(rest_forward_vector) < 0) {
+					prev_forward_vector.dot(rest_forward_vector) < 0 &&
+					forward_vector.dot(rest_forward_vector) < 0) {
 				init_transition();
 			}
 		} else {
 			if ((is_not_max_influence || !Math::is_equal_approx(primary_positive_limit_angle + primary_negative_limit_angle, (float)Math::TAU)) &&
-					prev_forward_vector_nrm.dot(rest_forward_vector) < 0 &&
-					forward_vector_nrm.dot(rest_forward_vector) < 0) {
+					prev_forward_vector.dot(rest_forward_vector) < 0 &&
+					forward_vector.dot(rest_forward_vector) < 0) {
 				init_transition();
 			}
 		}
@@ -596,7 +596,7 @@ void LookAtModifier3D::_process_modification(double p_delta) {
 		remaining = MAX(0, remaining - time_step * p_delta);
 		if (is_flippable) {
 			// Interpolate through the rest same as AnimationTree blending for preventing to penetrate the bone into the body.
-			Quaternion rest = skeleton->get_bone_rest(bone).basis.get_rotation_quaternion();
+			Quaternion rest = bone_rest.basis.get_rotation_quaternion();
 			float weight = Tween::run_equation(transition_type, ease_type, 1 - remaining, 0.0, 1.0, 1.0);
 			destination = Animation::interpolate_via_rest(Animation::interpolate_via_rest(rest, from_q, 1 - weight, rest), destination, weight, rest);
 		} else {
diff --git a/scene/3d/look_at_modifier_3d.h b/scene/3d/look_at_modifier_3d.h
@@ -53,7 +53,7 @@ class LookAtModifier3D : public SkeletonModifier3D {
 	Vector3::Axis primary_rotation_axis = Vector3::AXIS_Y;
 	Vector3::Axis secondary_rotation_axis = Vector3::AXIS_X;
 	bool use_secondary_rotation = true;
-	bool relative = true;
+	bool relative = false;
 
 	OriginFrom origin_from = ORIGIN_FROM_SELF;
 	String origin_bone_name;

Original file line number	Diff line number	Diff line change
`@@ -204,8 +204,9 @@ void AimModifier3D::_process_constraint_by_node(int p_index, Skeleton3D *p_skele`
`204`	`204`	`if (!nd) {`
`205`	`205`	`return;`
`206`	`206`	`}`
`207`		`- Vector3 reference_origin = nd->get_global_transform_interpolated().origin - p_skeleton->get_global_transform_interpolated().origin;`
`208`		`- _process_aim(p_index, p_skeleton, p_apply_bone, reference_origin, p_amount);`
	`207`	`+ Transform3D skel_tr = p_skeleton->get_global_transform_interpolated();`
	`208`	`+ Vector3 reference_origin = nd->get_global_transform_interpolated().origin - skel_tr.origin;`
	`209`	`+ _process_aim(p_index, p_skeleton, p_apply_bone, skel_tr.basis.get_rotation_quaternion().xform_inv(reference_origin), p_amount);`
`209`	`210`	`}`
`210`	`211`
`211`	`212`	`void AimModifier3D::_process_aim(int p_index, Skeleton3D *p_skeleton, int p_apply_bone, Vector3 p_target, float p_amount) {`