68 votes
Date Updated: 
Author Name: 
Matthew Dicks


 Joint Bend Rig Elbow Setup PreviewJOINT BEND RIG Shoulder Setup Preview

A Tool to greatly speed up and simplify the process of skinning the joints of characters,especially shoulders and hips which are notoriously difficult to skin. THE NEW VERSION 2 OF THE JOINT BEND RIG HAS A BIAS CONTROL TO CONTROL THE AMOUNT OF TWIST IN THE JOINT


Additional Info: 

The joint bend-rig is designed to quickly set up skinning for bending and twisting motions.
Just merge the bend rig in the max file with your current scene making sure to get all of its parts. ( i recommend grouping it before merging to ensure a clean merge ). Or use it as part of a new rig that is being set up.


There are now 2 new beta versions of the bend rig available that improve on the old versions in several ways. I am calling them version 3 and version 3.5 optimized.


-Version 3 fixes an issue with the bias control that was occuring with the old version 2. The bias controls in version 3 now work perfectly at all angles and bias values. It also has 2 new types of bias controls that allows you to control the twist and tilt from the center of the bend in addition to bias controls for both ends of the cross sections. This gives a great deal more control over the type of twist and bend that is happening in the joint.

Version 3 also has been completely rebuilt and now has a more streamlined design for better performance than version 2. There are a couple of setups in the bend rig 3 file that allow you to see how the bend rig can be set up and the effects of the new bias controls can be seen by playing around with the values at different bend angles. The setup for a hip joint can still be seen in the file for version 2 but i recommend using version 3 for serious projects.


-version 3.5 optimized is a stripped down optimized version of version 3 that uses about 85 percent scripted wiring to acheive the bending and twisting. The idea behind version 3.5 is to optimize and improve the performance of the bend rig when using multiple bend rigs on a character by using mostly scripted wiring to acheive the bending and twisting motion as opposed to mostly position and orientation constraints that are used by version 3. It can be used when the advanced level of control given by version 3 of the bend rig is not needed.

-It differs from version 3 in that it only has one bend arm rather than 2 and also it only has one bias control. This will be enough for many rigging situations.

-To use the bend rig in the opposite direction one just has to mirror it while grouped.

Version 3.5 optimized also has several other features that allow even greater control over its performance.

First any cross section ( except for cross sections 1 , 5 , and 9 ) can be deleted from the rig without affecting the proper bending and twisting of the rig. This means less objects being calculated in the bending motion. In many cases skinning to just 5 cross sections ( 1, 3 , 5 , 7 , and 9 ) will be enough to create good deformation or even 3 ( 1 , 5 , and 9 ).

As long as cross sections 1 , 5 , and 9 are not deleted or altered the bend rig will still function properly.

The bias cross section and bias control can also be deleted if they are not needed. ( to delete the bias cross sections i recomend first deleting the 2nd one then the 1st then the 3rd)
The bias control will still work if the bias cross sections are not there but if the bias control is not needed it can also be deleted. An example of the bend rig 3.5 with deleted cross sections is included in the max file.

I have fully tested both of these versions and have encountered no issues, but i recommend testing them out fully yourself before using them for serious projects.

I am keeping bend rig 2 file available for now because it still has the example setups for shoulders and legs. You can still use that to test out the bend rig but i reccomend using version 3 and 3.5 for serious projects. I may do a few extra example setups that show the bend rig being used for all joints on the body including one that shows the optimized bend rig being used to skin all of the joints of a hand.

Looking at the video tutorial for the fast setup of a shoulder joint will give you a good idea of how it can be set up.

The bias controls have custom attributes in there modifier stacks that give a great deal of control of twisting and tilting of the bend cross sections. The effect of changing the bias settings can be viewed by changing the bias settings at different angles in the animation on the shoulder and pelvis that are already set up in the max file.

This bias custom attribute can also be wired to a reaction with joints enabling different bias settings at different angles much like biped twist poses. There is a specific technique that i have found is necessary to do this though. I discuss this in a document included with the file.

The bend rig has two types of cross sections. A set that creates the bending motion and an extra set of cross sections that can be skinned to, too distribute the twist further into the limb itself which constitutes it's own twist links system for effects like upper arm twist, wrist twist, thigh twist, etc. The length of the cross sections can be adjusted by moving the bias control in and out.

This can also be used in conjunction with twist links that are already set up on your rig, say if a bend arm were linked to a twist link of your rig the twist links of the bend rig can be used to blend between them.

For examples of the bend rig used to setup a hip joint see the older versions zip file which i have still made available only so that the example setups in the max file can still be accessed.

Note: most joint bend rig parts have explanations in the object properties user defined area. Also the text in the viewports have explanations in there object user defined properties.

Just merge the bend rig in the max file with your current scene making sure to get all of its parts. ( i recommend grouping it before merging to ensure a clean merge but I also reccomemd ungrouping it after the merge). Or use it as part of a new rig that is being set up.

The bend rig has two rectangle bend arms and a com joint ( which is dark blue in the max file). The bend arms are what control the bending motion of the cross sections and these are what should be linked to your rig parts ( example: clavicle and upper arm) the com joint controls the center of the bend and you will most likely want to link it to the parent joint ( example: clavicle) the cross sections are not meant to be moved themselves but only controlled by the bend arms and com. You will also notice that if you move the bend arms the bend rig cross sections will stretch, good for stretchy joints ( version 3 only ) . Initially the bend arms are linked to the com joint and the whole bend rig can be moved by moving just the com joint.

To resize it position it and clone it , group all of its parts and scale it uniformly (i recommend ungrouping it afterwards , note: also when cloning it do not move it far or use edit clone. If it is moved to far when cloning some of the parts may be left behind, I thnk this is some kind of cloning issue in max.

If you move it only slightly when using shift copy it will clone fine. Then you can move it to where it needs to be). Another note about grouping: remember that if any part of what you are trying to group is linked to something outside of the group the grouping will not be allowed so if you have linked the bend rig arms and com to something (i.E parts of your rig) already you will not be able to group the whole bend rig as one group)

The cross sections are what are meant to be skinned to and are what create the bending of the joints. Skinning to the bend arms is optional since you will probably just skin to your original rig for these joints (example upper arm and chest)

Skinning elbows, knees or any kind of joint with the bend rig, is fast and easy. Easily create deformations with nice creasing at any angle. The joint bend-rig is a series of objects that create an accordion like bending and twisting motion that is constant and even. It enables the maintaing of volume throughout a twisting and bending motion when a mesh is skinned to it. Thus even with little or no adjusting of envelopes or vertex weighting, when the bend rig is properly positioned in a joint, good deformations can be obtained. And when manual adjustment of weights is necessary the process is much more intuitive. Unlike spline ik which can give udesired random rotations around its links at different angles, the bend rigs bending and twisting motion at any angle is always constant and even. Also unlike spline ik, the bend rig can stretch. The joint bend-rig can be linked to any rig that has already been set up such as a biped or any rig that has already been set up for a character. Or it can be used as part of a new rig that is being created.

The file includes a max file with the bend rig with brief notes in the veiwport on how to set it up(basically what parts to link to what) it also includes some skinning examples showing the basic skinning. Just start rotatiing and moving the arms of the bend rig and you can get an idea of how it should be used. The cross sections of the bend rig are what create the bending motion and what should be skinned to. They are not meant to be moved themselves but are controlled by the rotating and moving of the bend arms and com (both marked with text in the viewport). The center of the bending motion can be changed by moving the com or bend arms ( version 3 only ) .

One more note: good creasing can be acheived using the bend rig alone but add to this the power of the relax and push modifiers and creases are even easier to control. An example of using the relax and push modifier with the bend rig is given in the max file.

I will try to be posting some more imfo and tutorials shortly. This has been tested on a character that i have recently set up but please let me know about any issues that are found.

The example setups from the older version of the bend rig can still be accessed here:

Also if anyone would like a version of this for an earlier version of max please let me know and i will see if i can produce one.



You may have to press the button a few times to view the third link. Also the maximize button might not work. You should be able to download the video tutorial with real player or any flash player that can download from the web. Still working on a better solution but at least those who cannot access veoh or youtube will be able to view it.

Version Requirement: 
max 8 and up
Video URL: 
BEND_RIG_VS_Standard_BONES_1.avi1.17 MB
BEND_RIGGED_Shoulder.avi1.32 MB
char_joint_motion_bnd_rig_tst1.mov2.01 MB
Bend_Rig_in_Shldr_demo_smllst_3.avi4.69 MB
Shoulder_Viewport_preview.avi1.87 MB
Pelvis_Bend_Rigged_avi.avi987 KB
BEND RIG 3 AND 3.5.zip768.59 KB


Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.
MAlice0409's picture

Refine it a bit and it will become a MUST for rigging

Just test your BendRig a little bit for one of my stick-man character, it works WONDERFULLY. I can't believed that I skinned it's knee within 30 seconds.

However, since a stupid like me don't know about the infrastructure of your rig are, all I see is a great module contains many unused things. No offense. It will haunt me pretty seriously when I have like a team of characters in the field. I think those unknown helix rings can made of splines instead of polygons so you can filter them out. You won't need to skin them anyway.

And I can't figure how to scale the Cross-sections to fit the "joint". I can only group them in order to scale them as a whole, until the Cross-sections fit the joiny, then I have to ungroup and readjusting those two controllers in their original place. It will be much more efficient if you can make those Cross-sections position themselves evenly when I move the "Arm" Controller, like some boxs hang on a path constraint.

You did a really amazing job to save our lives. Keep up the good work. :)

LisaF's picture

THANK YOU!!! This is my first

THANK YOU!!! This is my first time to rig a character, and I didn't make it easy on myself (she really realistic). She is also higher poly than she should be because I lost the low poly version in a crash! So her shoulder has been giving me a tremendous amount of trouble! This looks like it should work tho, THANKS and wish me luck

kenmac's picture

where is the script?

where is the script?


Glad It Helped.

Glad It Helped.

Bobbonkers's picture

If you need a character with

If you need a character with his shirt off this tool is fantastic, it will save you hours of work, hassle and headaches.
Matscrptart, I can't thank you enough.


This is a tool and technique

This is a tool and technique that I have found to be very powerful and save me a lot of time and headache. I am happy to share it with all and hope others find it to be useful.

mhdmhd's picture

I thought this a script but

I thought this a script but it is not, but can it be a script and apply it to a normal rig.

Did you see this similar function in xsi, it is wonderful.

But in general, it is some great work you have achieved.

Mahmoud ElAshry

Antigollos's picture

Hi all, (sorry for my bad

Hi all,

(sorry for my bad english)

i also did not find a script. I finally found out that there is no script - its a method which matthew is showing us. you can find his workaround in the "BEND RIG 3 AND" as a usual max file.

the thing is just - i can't see through this (for me) very complex method. i am a noob and i thought i get a nice rollout with some new buttons or so xD

but in that case it's a big misterious workaround from a pro... "nothing" for us noobs :-(

if there would be a step-by-step tutorial, THAT would be sooo great *crying* xD

filled with humbleness,

antigollos *-*

cbaker9552's picture

I Can't find the script!

I Can't find the script!


That would be great. I have

That would be great. I have been trying to redesign this post to be a more pleasant design for a while. I would have changed all that a little while ago. But recently I have been hesitant to alter parts of this post because I have had some problems with the post updating properly. Sometimes I will try to change something and press the post button, and the post will not update at all. Perhaps I just am not trying to update it properly.


Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.