Working with MotionBuilder in 3ds Max - Part 5 - CAT Rigs

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  • Games
  • Animation
  • 2011
  • Character Animation
  • 3ds Max
Skill Level
  • Advanced
6 min

Working with MotionBuilder in 3ds Max - Part 5 - CAT Rigs

Once you have characterized your CAT rig and animated it in MotionBuilder, you import the animation back to 3ds Max for rendering. The process is a bit different from what you have learned earlier but easy enough once you understand the workflow.


  • Recorded in: Motionbuilder 2011, 3ds Max 2011
  • This tutorial is intended for use with 3ds Max version 2011 or higher.


00:00:00 --> 00:00:06
Now that you have exported your animation from Motionbuilder,
you will import it to use on your CAT rig in 3ds Max.

00:00:07 --> 00:00:10
Reopen the original file in 3ds Max. You will start with a clean file.

00:00:11 --> 00:00:16
The process of importing a Motionbuilder animation onto a CAT rig
is different from what you have seen before.

00:00:16 --> 00:00:22
It is not enough to "update" the skeleton elements as you have done
with bones and biped skeletons.

00:00:22 --> 00:00:28
You need to add the animated skeleton to the scene and then "capture"
that animation onto the CAT skeleton.

00:00:28 --> 00:00:31
Furthermore, there is a very important rule to take into account:

00:00:32 --> 00:00:37
CAT spines, like back spines and necks, are based on procedural controllers.

00:00:37 --> 00:00:41
These will not work when using a capture animation workflow.

00:00:41 --> 00:00:46
For spines to react to FK animated bones, they need to be keyframable.

00:00:46 --> 00:00:54
If you select a back spine element on your superhero skeleton,
you will notice in the Modify panel that the control is set to Procedural.

00:00:54 --> 00:00:59
Change that option to Keyframed and then click Yes to dismiss the Warning.

00:01:00 --> 00:01:07
Select a Neck bone and do the same. If you had additional spines
to your character, you would need to adjust those as well.

00:01:07 --> 00:01:11
You are now ready to import the animated punch you saved in Motionbuilder.

00:01:12 --> 00:01:16
Insert the fbx file but do not dismiss the FBX Import dialog just yet.

00:01:16 --> 00:01:20
So far, you have mostly accepted the defaults when using this tool.

00:01:21 --> 00:01:28
However, in this case, it is not enough to update the scene elements.
You need to choose the Add to scene option this time around.

00:01:28 --> 00:01:34
This brings in an additional bones character that contains
the animation data of the punch motion.

00:01:37 --> 00:01:42
The trick is to retarget your CAT rig
to the Motionbuilder-based bones skeleton.

00:01:42 --> 00:01:47
This is done by using the CAT Capture Animation tool found
in the Animation menu.

00:01:48 --> 00:01:53
In the Capture Animation dialog, expand the CATRig Mapping rollout.

00:01:53 --> 00:01:58
In order to retarget your CAT rig to the skeleton, you need to use it
as a Target object.

00:01:58 --> 00:02:01
The bones skeleton is your source.

00:02:02 --> 00:02:08
Click the Source Objects button and select the bones skeleton's pelvis.

00:02:13 --> 00:02:17
Select the Target Rig button and choose the pelvis on your CAT rig.

00:02:18 --> 00:02:23
To map the two together, you can try using Auto Map, but you will
probably need to help it a bit.

00:02:24 --> 00:02:29
Select unassigned Source Nodes and drag them as Target Nodes
in the right pane.

00:02:50 --> 00:02:53
Do NOT dismiss the dialog just yet.

00:02:55 --> 00:03:01
At this time, the CAT rig is retargeted to the bones skeleton nicely
but is still dependent on it.

00:03:05 --> 00:03:11
If you select a CAT bone and go to the Motion Panel, the motion layer
that got created is still based on the source motion capture.

00:03:12 --> 00:03:15
This becomes evident if you try to turn off that layer.

00:03:16 --> 00:03:21
To make the animation an integral part of the CAT rig, you need to bake
the animation onto it.

00:03:22 --> 00:03:25
This is done by clicking the Capture Animation button.

00:03:25 --> 00:03:33
This creates a new CollapsedLayer motion layer, and this time,
turning off or even deleting the mapping layer doesn't affect the motion.

00:03:36 --> 00:03:39
Now you can dismiss the Capture Animation dialog.

00:03:40 --> 00:03:45
You can also get rid of the bones skeleton as you don't need it anymore.

00:03:53 --> 00:03:57
This leaves you with an animated CAT rig.

00:04:00 --> 00:04:06
If you need to relocate your character, you can use
the Layer Transform Gizmo to do that.

00:04:37 --> 00:04:43
If you need to make simple adjustment offsets to the animation,
you can of course use Adjustments Layers.

00:04:49 --> 00:04:54
With this movie set, you have learned three different workflows
between 3ds Max and Motionbuilder.

00:04:54 --> 00:05:02
Using a Character Studio Biped is arguably the easiest solution because it's
easy to create in 3ds Max, and its rigging is automated in Motionbuilder.

00:05:02 --> 00:05:09
A CAT skeleton is certainly easy enough to create in 3ds Max,
but the interoperability with Motionbuilder requires a little more effort.

00:05:09 --> 00:05:15
Both Biped and CAT allow for simple layer adjustments after
the animation data has been brought back to 3ds Max.

00:05:16 --> 00:05:22
Working with simple Max bones is the most manual of approaches
as you have to build a skeleton manually,

00:05:22 --> 00:05:27
and there are no easy ways to adjust the animation in 3ds Max after
you have imported it from Motionbuilder.

00:05:28 --> 00:05:34
However, you can always go back to Motionbuilder for further adjustments
and bring the animation back to your 3ds Max bones skeleton.

00:05:34 --> 00:05:40
All these workflows are acceptable and which one you end up using depends
largely on your own choice and personal preference.

00:05:41 --> 00:05:47
This concludes this 5-part series on Interoperability between 3ds Max
and Motionbuilder. We hope you have enjoyed it.
Posted By
  • 3ds Max
  • Animation
  • 2011
  • Character Animation
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