Robotic Rigging and Bone Constraints Problem

I’m trying to get two bones to attach to a single object in a way that keeps the transformation of the red line static.

I’ve tried restricting the movement of the bone within the IK chain (pictures show that there are no restrictions, but I did try) to allow zero rotational movement, but the “Neck Base” still rotates weirdly and not smoothly. It reacts the same way without any of said rotational restrictions, if that helps.

I do have a Bone Constraint on both “Neck Rod Front” and “Neck Rod Back” to share the same rotation angle in only one axis as shown.

Is there a way to connect “Neck Rod Back” to the “Neck Base” to maintain that angle?

Is there a better way to complete this method of movement?

Here’s a link for the file for testing.

Pictures and GIF:






Gif https://imgur.com/izsHB5I
https://imgur.com/izsHB5I

So, five things to start with:

  1. Welcome to BA! :slight_smile:

  2. Please don’t double post - you are on moderation meaning your first ten posts have to be approved by a Mod before they appear, so please be patient and wait for them to show, it all depends on how busy the Mods are.

  3. Please don’t use Upload sites that want money for their services, use pasteall.org/blend - its free, run by the same guys as this website and doesn’t bombard me with adverts…

  4. Your cannot bone parent one object to two bones - you need to add a bone to do the job, linked to other bones to keep it in place.

  5. I don’t have time before I go on my hols to explain everything that is wrong with your armature… :slight_smile:

But this is how you do a parallelogram rig in Blender:


Blend File: para.blend (434 KB)

Just rotate bone “crank-1” to operate it.

Try to make your IK chains connected, not with gaps everywhere - put the bone connections at the centre of rotation of the joint, also your chain lengths for the arms are different, not good practice! The “Root” bone should be on the floor between the feet, or tracks in your case, parent major bones and IK targets to them. Don’t have limb bones floating in mid air - connect them to the major “spine” type bones - makes for a much easier life.

DON’T Scale or rotate object meshes, or armatures for that matter in Object Mode!!! That is what Edit mode is for, do all edits in Edit mode: :ba:


Just one example of many - if you must scale/rotate in object mode Apply the scale/rotation afterwards by keying CTRL+A => “Rotation and Scale”.

I am sure others will help you in my absence, if not I will be back early Feb. I would advise you read the manual for IK chains and look at Nathan Vegdahl’s “Humane Rigging” tutorials to get a good start in rigging.

Cheers, Clock. :slight_smile:

I forgot to ask where you got the meshes from - Tris (three sided polygons) are not preferred for Blender, you should model in Quads (four sided polygons). Also there are loads of ugly tris on a flat plane in places where a simple Quad would be a much better solution, here’s several examples:


Yuck!!! - (where’s the “puke” emoji?)

Now I really must get on with the packing…

Cheers, Clock.