Luxo Lamp Armature

Support Animation and Rigging
1

http://www.premdesign.com/rel_tuts/lamp_overview.jpg
lamp_overview.jpg659×655

Having set up bikes and I am surprised am struggling with this lamp rig.

Anybody has a tip how to setup this dual arm rig? The solution is probably
simple and I am not seeing the forest because of all the trees …

here is an attempt. All works somewhat fine, the center and tip mesh triangular bases
are stable. This is done with parenting them to those triangular bone structures
which all do not inherent the rotation from the parent bone.

But what I would like to be able is to make the lamp bone IK.

but than this happens

The problem is that those triangular bone rings which help to stabilize
the second arm, are of course only parented to one bone and not both bone
which explains why it opens.

Any idea about how to do that?

Here is the Blend file: http://www.pasteall.org/blend/2391

2

ouch it making my head hurt. I’m thinking some track to and copy loc constraints could be used.

3

You don’t need to model all those triangular structuers with bones. The lamp articulation structure is made to keep the lamp head always orient the same no mater how the arm is folded. You just need two main articulation bones, say the two lower bones in each segment, and then constraint the two other bones (thus the upper bones in each segment) to orient like the two corresponding lower bones. Then, add a bone that is always oriented up for the two trianglular pieces. That’s all. This should be a very simple rig.

4

YPOISSANT

I tried to understand your direction but maybe I am lost in translation here.

So you talk about each a pair of bones for the dual struts
plus each a bone for the two articulation structures.

I am not sure how I have to understand your contraint direction the bones for the opper struts
are orientated the same way as the bones of the lower struts. I must misunderstand something here.

In addition to throw in each a bone for the triangular join parts - which than makes me ask myself
what you mean with articulation structures. Aren’t those the same?

http://www.pasteall.org/pic/show.php?id=2459

5

I tried a more simpler approach with a single bone structure
and trying to address you suggestions with those bones for the
triangular structures.

The mesh structure now uses just track to constraints and the bones
are moving the triangular structures only.

but again in FK it works in IK it does not. I added an orange ball
to show where the tip of the blue bone (first triangular joint) should be.

Tried some constraints but it does not work.

http://www.pasteall.org/pic/show.php?id=2460

6

Hi.
Here is my setup and I hope it helps you a bit.
Rig setup needs some rotation limit constraints to prevent struts overlaping.

http://img545.imageshack.us/img545/9640/luxorig.png

Attachments

LuxoRig.blend (87.1 KB)

7

Stiff IK solvers - brilliant. Well that takes care of the stiffness!

BTW the upper strut bone needs the inherent rotation deactivated.

8

Oups! I missed the IK requirement. Sorry. Then, of course. my simple setup will not work.

9

@ ypoissant

ah no I dont feel so silly anymore. Yah the IK requirement was a nut I was not able to crack on my own.
Jawra’s IK Solver trick is fully doing the job, stil surprised how many steps you need to take to make this work. besides the IK solver you also need to activate a lot of x,y,z restrictions.