Using CAT in 3ds Max - Part 3 - Absolute Layers

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8 min

Using CAT in 3ds Max - Part 3 - Absolute Layers

In this tutorial, you learn about CAT animation layers and most notably the Absolute Layer. You will also learn how to apply multiple layers and blend the motion between them.


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


00:00:00 --> 00:00:04
Now that you know how to build a CAT rig, you'll take a look
at how to animate it.

00:00:05 --> 00:00:09
For the purpose of clarity, you'll work with a simple rig
with no skinned mesh.

00:00:09 --> 00:00:15
In a new scene, create a Basic Human rig;
this is one of the simpler rigs available.

00:00:21 --> 00:00:29
Select the left hand and set the number of digits to 2. Having two
fingers will it make easier to read the orientation of the hand.

00:00:32 --> 00:00:38
Adjust the digits by setting their number of bones to 1,
and by adjusting their sizes.

00:00:44 --> 00:00:51
Once done, select the hand, copy the pose, and then mirror/paste it
to the opposite hand.

00:00:57 --> 00:01:01
Select the top parent (the triangular base node)
and go to the Motion Panel.

00:01:01 --> 00:01:06
By default, you are in setup mode as the animation toggle button is red.

00:01:06 --> 00:01:12
To animate a rig, you first need to have an animation layer active;
otherwise, you cannot go into animation mode.

00:01:13 --> 00:01:22
There are four options in the Add Layer flyout, Absolute layers, Local &
World adjustments layers and a special type called CAT Motion layer.

00:01:23 --> 00:01:29
If you followed the first two movies in this series,
you already dabbled a bit with the CAT Motion layer.

00:01:29 --> 00:01:36
We'll leave the CAT Motion layer for later as we take a look
at the other layer types. We'll come back to it later in more detail.

00:01:37 --> 00:01:40
First, you'll start learning about the Absolute layer.

00:01:40 --> 00:01:46
Create an Abs. Animation layer. Notice that once it's created,
you can now go into animation mode.

00:01:47 --> 00:01:56
The Abs. Animation layer is the layer of choice for keyframing your rig,
but you can also use it to import animation files,
including Motion Capture files.

00:01:57 --> 00:02:02
Enable Auto Key. You will animate the right arm to simulate a handshake.

00:02:06 --> 00:02:12
Go to frame 30 and move and rotate the right hand to initiate a handshake.

00:02:28 --> 00:02:33
Go to frame 40 and move the hand down and rotate it slightly.

00:02:38 --> 00:02:56
Repeat the procedure at frames 50, 60 & 70.

00:03:03 --> 00:03:10
Notice that when you create a keyframe for the hand, you are also
creating keyframes for the entire arm chain (upper and lower arm).

00:03:11 --> 00:03:17
This is significant because if you want to copy a keyframe,
for example to bring back the arm to its original position,

00:03:17 --> 00:03:24
then you need to select the whole arm (by double-clicking the upper arm),
and then shift move a keyframe to copy it.

00:03:28 --> 00:03:32
So now you have an animated layer for the right arm.

00:03:37 --> 00:03:40
Rename it: RHand Shake.

00:03:46 --> 00:03:50
Create a new Absolute Animation Layer and rename it LHand Wave.

00:03:50 --> 00:03:53
You will use this layer to animate the left hand.

00:03:54 --> 00:04:00
Animation layers are evaluated top to bottom.
This means that the new layer totally overwrites the previous one.

00:04:01 --> 00:04:04
Notice that the handshake animation is not active anymore.

00:04:05 --> 00:04:12
Like you did earlier, animate the left hand, this time to simulate
a simple wave to the crowd.

00:04:35 --> 00:04:39
If you want, animate the head to look in the direction of the wave.

00:04:42 --> 00:04:48
Do not worry about the quality of the animation at this time;
this is more to study layer management.

00:04:51 --> 00:04:53
Disable Auto Key when you are done.

00:04:54 --> 00:05:00
So now you have two animation layers, each controlling the animation
of one arm, with the second layer overwriting the first.

00:05:01 --> 00:05:05
You can blend the animation between layers by adjusting layer weights.

00:05:05 --> 00:05:11
This can be done globally, affecting the whole rig, or locally,
affecting selected limbs.

00:05:11 --> 00:05:17
To see this better, switch the Rig Coloring Mode from skeleton color
to layer color.

00:05:17 --> 00:05:24
Now the rig color reflects that of the layer that affects it,
in this case the second overriding layer (LHand Wave).

00:05:25 --> 00:05:29
Change the layer colors to something contrasting like Blue and Red.

00:05:37 --> 00:05:45
Play back the animation. At this time, the rig is red and the left arm
is animated, as specified by the color and the animation data of that layer.

00:05:46 --> 00:05:52
With the LHand Wave layer selected, drag down the Weight value slowly
all the way to 0.

00:05:52 --> 00:05:53
Two things happen:

00:05:54 --> 00:06:02
the rig color gradually turns from red to blue, and the animation
gradually shifts from the left hand's waving to the right hand's shake.

00:06:02 --> 00:06:12
As you can see, the Global Weights affects the whole rig. At Frame 50,
right in the middle of both arm animations, you get a 50-50 blend.

00:06:18 --> 00:06:21
The weight value is totally animatable of course.

00:06:22 --> 00:06:27
With Auto Key enabled, set it to 0% at frame 40,

00:06:30 --> 00:06:33
and to 100% at frame 80

00:06:37 --> 00:06:40
Set it to 100% at frame 20,

00:06:42 --> 00:06:46
and 0 % at frame 60.

00:06:57 --> 00:07:02
The little icons next to the weight values provide you
with a quick link to the weights function curves.

00:07:03 --> 00:07:06
This makes it easier to adjust the weights keyframes.

00:07:10 --> 00:07:12
Delete all the weights keyframes for now.

00:07:13 --> 00:07:17
In addition to global weights, you can also use layer weights locally.

00:07:18 --> 00:07:22
This is useful when you want to use different animations
for different limbs.

00:07:22 --> 00:07:27
Select the right upper arm. (Selecting the right clavicle
or the right forearm would work as well).

00:07:28 --> 00:07:29
Go to Frame 0.

00:07:30 --> 00:07:35
Make sure the LHand Wave layer is selected and bring down
its Local Weight value to 0.

00:07:35 --> 00:07:42
The whole right arm turns blue, signifying it is no longer
affected by that layer, but by the one below it.

00:07:43 --> 00:07:51
Scrub the animation. Notice how the skeleton for the most part moves with
one animation layer, while the right arm is affected by another layer.

00:07:52 --> 00:07:59
By stacking these layers and animating their weights, you can achieve
an interesting blend of animations on the whole rig, or on specific limbs.

00:08:00 --> 00:08:03
In the next movie, you take a look at Adjustment Layers.
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  • 3ds Max
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