Skin Wrapping in 3ds Max - Part 1 - Variations

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Industry
  • Games
Subject
  • Modeling
  • 2012
Products
  • 3ds Max
Skill Level
  • Intermediate
Duration
12 min

Skin Wrapping in 3ds Max - Part 1 - Variations

In this tutorial, you will learn about the Skin Wrap tool and deforming objects tool. It is flexible enough to have a variety of uses but what it's really great at is transfering skinning data from one character to another.


??Notes
  • Recorded in: 3ds Max 2012
  • This tutorial is intended for use with 3ds Max version 2012 or higher.

Transcript??

00:00:00 --> 00:00:06
Skin Wrap is usually used to have a low-resolution mesh drive the animation
of a high-resolution mesh.

00:00:07 --> 00:00:10
Practically however, its use is somewhat different.

00:00:10 --> 00:00:18
For example, its application in the gaming industry is to use Skin Wrap
to transfer skinning data from one character to another.

00:00:19 --> 00:00:26
Many times in a gaming project, you have to duplicate characters
that look somewhat alike but with slight variations.

00:00:26 --> 00:00:33
Two soldiers may look similar but one may have an extra pouch on his uniform
while the other may carry an extra gun belt.

00:00:33 --> 00:00:38
Other variations may include fat, medium or skinny characters in a crowd.

00:00:39 --> 00:00:47
As long as these characters have the same general build, meaning general height and proportions,
then you can transfer skinning data effortlessly.

00:00:48 --> 00:00:52
In that case, they can all share the same skinning template and rig.

00:00:52 --> 00:01:01
It is important therefore to be able to "recycle" your work,
given that properly skinning a single character can take hours or even days.

00:01:02 --> 00:01:09
After properly skinning a single character, you can then transfer that information
in a matter of minutes or even seconds using Skin Wrap.

00:01:10 --> 00:01:16
The scene you will be using here has a few objects, mainly characters, but also a biped skeleton.

00:01:16 --> 00:01:22
The main character, named "Full-Body" has already been properly skinned to the Biped skeleton.

00:01:22 --> 00:01:31
The Biped at this time is in Figure mode, but if you exit Figure Mode,
you can see the animation used to test the skinning.

00:01:40 --> 00:01:43
Go back into Figure Mode to get the initial pose back.

00:01:44 --> 00:01:53
This particular example is using a Biped skeleton but Skin Wrap works equally well
with any type of skeletons, be it Biped or CAT or simple Bones.

00:01:54 --> 00:01:59
Select the two characters to the left and hide them; you'll only use them in Part 2 of this series.

00:02:00 --> 00:02:03
Zoom in and take a look at the remaining characters.

00:02:03 --> 00:02:08
The main (skinned) character on the left and the one in the center are very much alike.

00:02:08 --> 00:02:13
They have the same topology and you can tell that one was used to create the other.

00:02:13 --> 00:02:21
There are some slight variations such as a pouch and a bandage on the character's right leg,
a knee pad on the left,

00:02:21 --> 00:02:27
the torso has some wacky protruding design and there are some extra laces on the left forearm.

00:02:28 --> 00:02:31
The warrior character on the extreme right is totally different though.

00:02:32 --> 00:02:36
The topology is nowhere near and you can see that it was designed and built independently.

00:02:37 --> 00:02:43
However, in terms of general height and proportions, the two characters do have something in common.

00:02:44 --> 00:02:51
Let's take one problem at a time, select the warrior and hide it.
You'll concentrate on the two characters with slight variations.

00:02:51 --> 00:02:59
If you select the main character, you will notice that its pivot point is between its feet,
located at world coordinates [0,0,0]

00:03:00 --> 00:03:05
This is typical when you model a character and will make it easier to position
the other characters you want to skin wrap.

00:03:06 --> 00:03:12
Select the "Variations" character and notice that it too has its pivot point between its feet.

00:03:13 --> 00:03:17
For Skin Wrap to work, the two objects have to be on top of each other.

00:03:17 --> 00:03:22
Relocate the character to [0,0,0] so that its sitting on top of the original.

00:03:23 --> 00:03:29
Notice also that both have the same initial pose. This is important for Skin Wrap to work properly.

00:03:29 --> 00:03:35
In wireframe mode, notice also that besides the obvious variations, like pouch and chest logo,

00:03:36 --> 00:03:39
there are some less obvious variations around the shoulder areas.

00:03:39 --> 00:03:44
All this to say that the two models do not have to be exactly identical.

00:03:44 --> 00:03:51
With the Variations model selected, go to the Modify panel and apply a Skin Wrap modifier.

00:03:52 --> 00:03:57
Before choosing a Control object to drive your mesh, take a look at some of the options.

00:03:57 --> 00:04:01
You can drive the deformation by Vertex or Face types.

00:04:01 --> 00:04:05
Which one you choose will depend largely on the object at hand and your personal preference.

00:04:06 --> 00:04:12
Many riggers in the games industry seem to favor Face Deformation, so go ahead and use that one.

00:04:12 --> 00:04:16
The Falloff value ranges from 0.001 to 10.

00:04:17 --> 00:04:27
This determines how vertices in the animated (or Control) object affect or pull vertices
in your selected object, referred to as a Base object.

00:04:27 --> 00:04:36
However, when using Face Deformation, it is often best to use a rigid transformation
by setting the Falloff value to 0.001.

00:04:37 --> 00:04:44
Next, you define a Control Object, in this case the Full-Body character
that is already skinned and animated

00:04:45 --> 00:04:48
In the Parameters group, click Add.

00:04:49 --> 00:04:52
Select the Full-Body character underneath the one you are working on.

00:04:52 --> 00:04:58
As 3ds Max processes this info, you get a status feedback in the bottom left corner of the screen.

00:04:59 --> 00:05:08
When it reaches 100%, make sure you right-click to cancel Add mode,
otherwise you may accidentally click another object and add it to the list.

00:05:08 --> 00:05:10
The process is now done.

00:05:10 --> 00:05:15
To test how Skin Wrap worked, select the biped's head and go to the Motion Panel.

00:05:16 --> 00:05:17
Exit Figure mode.

00:05:18 --> 00:05:20
Scrub the animation to see the results.

00:05:20 --> 00:05:31
Between frames 0 and 650, verify that the lower body worked correctly.
Notice how nicely the kneepad is behaving around frame 260.

00:05:36 --> 00:05:40
Check out the Torso between frames 660 and 1100.

00:05:41 --> 00:05:47
If you had to manually skin that chest logo, you would have had to spend a good deal of time on it.

00:05:48 --> 00:05:54
Hands, fingers and forearms can be checked between frames 1150 and 1950.

00:05:59 --> 00:06:07
As long as the Variations character is skin wrapped,
changes you make to the Control character (Full-Body) will be propagated to it

00:06:08 --> 00:06:13
At frame 1900, say you want to adjust the deformation of the forearm.

00:06:14 --> 00:06:22
Select the Full Body character. In the Modify panel, click Edit Envelopes
and select the 3rd ring of vertices from the wrist.

00:06:23 --> 00:06:30
Highlight the L_Forearm_2_Roll envelope in the list
and try some changes to the Abs. Effect value.

00:06:31 --> 00:06:37
Notice that it updates both the Control object and the Base object, the one you skin wrapped.

00:06:38 --> 00:06:43
Once you're happy with the changes, you want to go back to your initial pose.

00:06:43 --> 00:06:48
With biped, it's a question of selecting a part of the skeleton and going into Figure mode.

00:06:53 --> 00:07:00
At this point, you can make your Base object (named Variations) independent
from the Control object driving it.

00:07:01 --> 00:07:08
With the Variations character selected, go to the Modify panel and click the Convert to Skin button.

00:07:09 --> 00:07:14
You now have a new Skin modifier with all the proper envelopes and vertex weights
assigned to your character.

00:07:15 --> 00:07:18
Notice how the Skin Wrap modifier has been automatically turned off.

00:07:19 --> 00:07:22
In fact you can now select it and delete it.

00:07:22 --> 00:07:24
You can now test the animation again.

00:07:25 --> 00:07:30
If there are any skinning areas that require tweaking, you can certainly address them.

00:07:30 --> 00:07:37
It will only take a fraction of the time tweaking a few vertex weights here and there
rather than having to skin this character from scratch.

00:07:40 --> 00:07:43
Skin Wrap probably just saved you a couple of days on your schedule.

00:07:45 --> 00:07:49
Hide the Variations character and from the Selection Sets list, choose Warrior.

00:07:50 --> 00:07:52
Click Yes to dismiss the warning.

00:07:52 --> 00:07:57
Make sure the biped is in Figure mode so that both characters are in the initial pose.

00:07:57 --> 00:08:02
As mentioned earlier, this character is quite different from the main Full Body character.

00:08:02 --> 00:08:06
The only things in common are general volume and proportions.

00:08:07 --> 00:08:13
Place the warrior character at [0,0,0] and repeat the procedure to skin wrap it
to the Control object.

00:08:28 --> 00:08:31
Select the Biped's head and exit Figure mode.

00:08:31 --> 00:08:34
Isolate the warrior and test the animation.

00:08:44 --> 00:08:48
For the most part, it's really not too bad at all.

00:08:52 --> 00:09:01
There are certainly some areas that require a bit of attention
such as under the arm pits noticeable between frames 1150 and 1950.

00:09:12 --> 00:09:18
The wrists also could use some adjustments, and that's noticeable around frame 1780.

00:09:24 --> 00:09:32
The head seems most problematic between frames 2250 and 2500,
but that's only because the warrior character actually has a head.

00:09:33 --> 00:09:38
The original Full Body character didn't. Skin Wrap didn't know what to do with that.

00:09:38 --> 00:09:45
The point is all these are simple tweaks that can be done
in a fraction of the time it takes to skin the warrior character from scratch.

00:09:46 --> 00:09:51
Go back to the original pose by selecting the biped's head and going into Figure mode.

00:09:56 --> 00:10:02
Select the Warrior character and convert Skin Wrap into a full Skin modifier.

00:10:12 --> 00:10:14
Delete the Skin Wrap modifier underneath it.

00:10:15 --> 00:10:23
Go into Edit Envelopes and select all the skin vertices that make the head.
Do not select the ones on the neck.

00:10:33 --> 00:10:40
Select the Bip001 Head envelope and set those selected vertices to an Abs. Effect of 1.

00:10:40 --> 00:10:47
This will ensure the head vertices are weighted to follow the biped's head only,
and no other bones.

00:11:01 --> 00:11:07
Similarly, you can fine tune the other areas such as wrists and armpits.

00:11:17 --> 00:11:25
Tweaking a few vertex weights here and there is a matter of minutes.
Skinning a full character from scratch is often a matter of days.

00:11:35 --> 00:11:37
Go back into Figure mode when done.

00:11:42 --> 00:11:48
Hide the warrior and from the Selection Sets menu, choose LODs. Dismiss the warning.

00:11:49 --> 00:11:54
In the next movie, you'll experiment using Skin Wrap with LODs (Level of Detail objects).
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  • 3ds Max
  • Modeling
  • 2012
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