Starting point for this tutorial.
In this tutorial, you will learn how to set up the bone system for a complex character. This will involve splitting a character apart, creating bones, adjusting bone strength, and putting the character back together.
For this tutorial, we'll start with a project file that already has the artwork for the character drawn - you'll just set up the bones. It's named "Tutorial 3.4" and it's located in the "Tutorials/3 - Bones" subfolder within the main Moho folder. Open this file in Moho, and you should see something like this:
Starting point for this tutorial.
There are six vector layers in this project, containing the body parts for this character. Although all the artwork could be drawn in one vector layer, it is often easier to draw a character in multiple layers, arranging the body parts from back to front, as shown below:
Starting point for this tutorial.
In order to make bone setup easier, the first thing to do is split apart the character. Choose the Edit->Select All menu command. All the points in the right arm (your right, his left) should be selected. Activate the Translate Points tool and drag the mouse to move the arm off to the side and up a bit:
Arm moved off to the side.
Next, select the Head layer, and move all of its points upward. Repeat the process for all the layers of the character, except the Torso layer, moving the body parts away from the center, as shown below:
Body parts split apart.
The reason we split apart the character is so that we can add bones to each part, while keeping the bones independent of each other. Later in the tutorial we'll put the character back together again.
The next step is to add bones. Add a new Bone layer to the project, and move all the vector layers into it, keeping the same order they are in now:
New bone layer.
Using the Add Bone tool, add two bones going up through the torso, starting with the bottom one:
Two new bones.
Next, add two bones to each arm, starting at the shoulder and going down - the shoulder bone should be parented to the upper torso bone. Then, add three bones to each leg, starting at the hip and moving down through the foot - the hip bones should be parented to the lower torso bone. Finally, add one bone in the head, parented to the upper torso bone. This figure shows all the bones in place:
All the bones added.
And this next figure shows the parenting of all the bones. The parenting arrows point from child bone to parent bone, and can be seen by activating the Reparent Bone tool:
All the bones added.
At this point, feel free to try using the Manipulate Bones tool to see how the bone system works so far. The body parts should mostly move how you would expect, but not totally cleanly - the next step is to clean up the bones' influence.
Double-click the bone layer in the Layers window to bring up the Layer Settings dialog. Go to the Bones tab and set the binding mode to "Region binding":
Turn on region binding.
When region binding is used, bones only move the points that lie in their region of influence. If a point is overlapped by multiple regions of influence, it will be affected by all the corresponding bones. If a point is in no bone's region of influence, it will move with the nearest bone.
This is different from flexi-binding, where all bones affect all points. Flexi-binding can be quicker to set up, but leads to more rubbery motion, since moving a hand will always cause a little bit of movement in a foot. Region binding makes separate body parts truly separate.
For region binding to work, however, you need to adjust the region of influence for each bone. To do this, activate the Bone Strength tool to display the bones' regions of influence:
Initial regions of influence.
Using the Bone Strength tool, click and drag on each bone in turn to adjust its region of influence. The correct adjustment for a region of influence it generally to surround the points along that section of bone. The most important regions are at the joints - the knees and elbows and such. Those are the areas where the regions of two bones overlap, and points will bend under the control of both bones. For parts like this character's head, the region of influence isn't very important - since there's just one bone, the points outside the region of influence will still move with that bone. Here's how you should adjust the regions of influence (don't worry about matching this exactly, just try to get kind of close):
Adjusted regions of influence.
Try using the Manipulate Bones tool again to test the bone setup. The character should move much more cleanly now - when moving an arm, for example, only that arm should move, and you should see no extra movement in other body parts.
The final step is to reassemble the character. Activate the Offset Bone tool. Click and drag on the top bone of each body part to move that part back into position. Move each arm by the upper arm bone, each leg by the thigh bone, and the head by its single bone. When each part is moved back into place, the character should look like this:
Re-assembled character.
Frame 0 is considered the "setup" frame for bones. When the time is set to frame 0, the character will still appear split apart (unless you're using the Offset Bone or Manipulate Bones tools). However, at other frames in the animation, the character will be re-assembled according to how you used the Offset Bone tool.
Try moving the character around again with the Manipulate Bones tool. The body parts will still move independently, even though they now overlap. Because the bones were set up on a split-apart character, that character could be re-assembled while still keeping the body parts independent.
Final character.
If you're interested in taking a look at the final Moho file, it's named "Tutorial 3.4 Final" and it's located in the "Tutorials/3 - Bones" subfolder within the main Moho folder.