How do I assing a copy_transform constraint to bones stored in different lists?

Question

So, I am writing a set of scripts to help me out with manual rigging in Blender. But I came across a problem when trying to assign constraints to 2 different groups of bones that I store in separate lists.

I store my deform and target bones in two separate lists using these lines of code:

def get_selected_pose_bones(self):
    """Get selected pose bones and store them in the list"""
    selection = bpy.context.selected_pose_bones
    self.pose_bones = []
    for bone in selection:
        self.pose_bones.append(bone)
    return self.pose_bones

#in rest of my functions I use:

def_bones = self.get_selected_pose_bones()
tgt_bones = self.get_selected_pose_bones()

and do all the necessary operations with those. But when it comes to assigning copy_transforms constraints I get stuck.

Basically, in pose mode I need to make the first bone in the list active and while it being active assign a copy_transform constraint, then I will need to assign a first bone from the second list as a target of the first bone's copy transform constraint. I have zero clue how to do that.

If someone dealt with something like this I would appreciate your help.

Answer 1

So, I have solved the problem I was facing.

To do that you will have to use the several operators in conjunction with some of your own logic. I used operators for selecting the object and then making it active. The use of following operators helped:

For selection and making objects active: bpy.ops.object.select_pattern()

if you use it in a for loop with bone's name list you can select every bone one by one.

Then to make a bone active you would use something like:

bpy.context.object.data.bones.active = bone_to_make_active
bone_to_make_active.select = True. 

The solution how to make bones active is available here on stackexchange, search for "how to make selected bone active".

Then you would use operators like:

bpy.ops.pose.constaint_add()

and then you would need to access constraints and edit it through context module:

bpy.context.object.pose.bones[bone.name].constraints["Copy Transforms"].target = bpy.data.objects['Armature']

And then you would need to access the subtarget value through context module again:

bpy.context.object.pose.bones[bone.name].constraints["Copy Transforms"].subtarget = bone_to_constraint[0].name

I know, it's not a copy and run kind of solution, but unfortunately I have my code split into separate classes and methods, it will be really time consuming to write one long method.