Introduction
This tutorial builds on the results of the previous two, teaching you how to add bones
to an object. You can either continue with the project you created in Tutorial 3, or
you can open a file provided for you named Tutorial3. This file can be found in the
Tutorials subfolder within the main Moho folder.
Bones are an important tool you can use in Moho to help make animation easier. If you
think of drawings in Moho (like the ones you made in previous tutorials) as soft rubber,
then bones can be thought of as stiff wires inside the rubber that help you move and
position the object. Bones are never displayed in a final rendering, they're just used
as tools during the animation process.
Bones are not absolutely necessary for animation, either. They are very helpful for
animating certain types of motion as we'll show in this and the next tutorial,
but there are other ways to animate in Moho as well. As you gain experience using
Moho, you'll learn when bones are appropriate and when they're not.
Importing an Object
Launch Moho and open the project from the last tutorial.
As you build a Moho project, there are times you may want to re-use objects you created
before. There's an easy way to do this, and we'll use it now to add a character to the
project. Select the File->Insert Layer... command. In the file dialog that
appears, open the file "TutorialExtras" that can be found in the Tutorials subfolder
within the main Moho folder. A dialog will open asking you which layer you want to use
from this project:
Select the layer named "Frank" on the left side of the dialog. On the right side,
you'll see a preview of Frank. Click OK. A new layer will be added to your project.
This layer is a copy of the layer Frank from the TutorialExtras project. Frank is
fully drawn and filled in - you can see what the scene really looks like now by
selecting File->Render.
Adding Bones
Lets give Frank some bones to make him easier to animate. In the Layer palette, click
the new layer button
.
In the popup menu that appears, choose "Bone Layer". Rename this new layer "Skeleton",
and drag the Frank layer upwards "into" the Skeleton layer. Finally, click the Skeleton
layer to make sure it's active. When this is done, the Layer palette should look like this:
In the main Moho window,
click the Bones tab near the upper left corner to switch Moho into Bone mode.
Make sure the layer "Skeleton" is selected in the Layer palette. While holding down the
Alt key, click the eyeballs in the Skeleton layer to temporarily hide the other layers.
Finally, use the Pan and Zoom tools to zoom in on the contents of this layer. Your
window should now show something like this:
Add a bone to Frank by selecting the Add Bone tool
and clicking and dragging upwards as shown below:
This will be the main control bone - you could think of it as Frank's spine. It should
look like this:
Click and drag out three more bones as shown below. It's important that you draw these
three bones in order from top to bottom: thigh, shin, and foot.
When a bone is selected, it is drawn in the highlighted color, red. When you add a
new bone, it becomes the "child" of the currently selected bone. The parent-child
relationship for bones means that the child can move around without affecting the
parent, but if the parent moves, the child will move with it. This is why it was
important to draw the previous three bones in order: the thigh bone's connected to
the spine bone, the shin bone's connected to the thigh bone, and the foot bone's
connected to the shin bone (at least in Frank's body).
When a bone is selected, it's displayed in red. Its parent also gets displayed
differently: in blue. The parent is highlighted like this for your information -
sometimes you may connect bones in the wrong order and looking for the blue parent
bone can help determine where things went wrong.
OK, let's add bones to the other leg. But first, we need to select the spine again
so that the second leg will also be attached to it. Use the Select Bone tool
and click on the spine to select it. Next, use the Add Bone tool
to add three bones to the other leg as shown below:
Testing Bones
There's a tool in Bone mode that lets you test how your skeleton structure is
working. Let's try that now. Select the Test Bones tool
and click and drag any of the bones you created. Try dragging several of the bones
around to see what happens.
Notice that Frank doesn't move at all - just the bones. The next step is to tell
Moho which parts of Frank should be attached to which bones.
The Test Bones tool doesn't permanently move the bones. Click the Select Bone tool
and all the bones will snap back into their original places.
Binding Points to Bones
Click on the Frank layer in the Layer palette. Moho will still be in Bone mode, but
now you're editing the Frank layer rather than the Skeleton layer. This distinction
is important - you add bones to a Bone layer, but you connect points to those bones
in a Vector layer.
Make sure the Select Bone tool
is chosen, then click to select the spine bone. Choose Edit->Select All to
select all the points in the layer. Finally, press the spacebar to bind the selected
points to the selected bone.
Next, click to select the right thigh bone. Use the Attach Points tool
to highlight the points in the right leg as shown below. Press the spacebar to bind
all these points to Frank's right thigh.
Continuing down the leg, use the Select Bone tool to pick the shin bone, and use
the Attach Points tool to select the points shown below. When the correct points are
selected, press the spacebar to bind them to the shin. Be careful that you only
select the points shown in the picture. You can also use the Attach Points tool to
de-select points that you don't want selected. Only press the spacebar to bind the
points when the correct set of points is selected.
Finishing off, select the foot bone and the correct group of points shown below.
Press the spacebar to bind the points to the foot.
Frank's other leg is just a mirror image of the first. Follow the same instructions
using the Select Bone tool
together with the Attach Points tool
to bind the points on the other leg to the bones in that leg. Remember, press the
spacebar to perform the actual binding only when the correct group of points is
selected.
Testing Bones (Again)
Once you bind points to bones, it's a good idea to test the skeleton again to make
sure everything works correctly. Pick the Test Bones tool
from the toolbar and click and drag on Frank's shin bones just above the ankle. If
everything was set up correctly, Frank should be able to move like this:
Play around - move Frank's bones around into various positions and get a feel for
manipulating the skeleton. For more information about Moho's bone mode, and detailed
descriptions of all the bone tools, the
Using Bones
chapter is a complete reference. The
next tutorial
will move into the Animation
editing mode, and you'll learn how to make objects move around over time.