Isolating Bones from Parenting (Pro Only)

When you assign a parent to a bone, Moho takes a snapshot of the parenting at that state. You can animate a bone that is on top of the parented bone (with independent angles, for example). But you typically don’t want to animate the bone that does the parenting because it has a snapshot taken of it and animation changes to the parent can cause unexpected changes in in the animation.

If you’re animating bones by hand, you should avoid animating the bone that another bone is parented to. Instead, use small bones to isolate the animation as shown in this example.

To follow this tutorial, you can either continue from the point at which you left off in Tutorial 3.8, or start with the Tutorial 3.8 Finished.moho project in your User Content folder.

1. Start with the project that you completed with the previous lesson, or open Tutorial 3.8 Finished.moho, which is located in your User Content folder.

2. Select Layer 3 as the current layer, and hide the other layers in the project.

.Select the Parenting layer and hide the other layers.

3. Scrub through the timeline. You’ll notice at frame 24 that the two outer arms reach down to the shorter arms in the middle. Then they move up again at Frame 36.

4. The two bone chains in the middle are already set up with bone dynamics, which are used in this tutorial in place of manual animation. The inner bone chains bounce in a springy manner. The inner left and right bone chains are identical except that the bone chain on the inner right has a small bone at the bottom. This bone will be used for parenting of the inner right bone chain so that you can understand the advantages of isolating bones in parenting.

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Bones

.The small bone for the inner right bone chain will be used for parenting.

5. Move to frame 24. Click the bottom bone in the middle left chain with the Select Bone tool.

6. Now switch to the Reparent Bone tool, and click the the top bone in the bone chain at the farthest left. In this bone chain, the bone dynamics will simulate what will happen when you try to animate bones that have a parent assigned.

.The lower bone in the inner left chain is parented to the top bone in the far left chain.

7. Now we’ll work with the set of bones at the right, which have the extra small bone that we will use for parenting. This small bone will help isolate the animation of the bone chain from the parenting. While still at Frame 24, select the small bone with the Select Bone tool.

8. Next, switch to the Reparent Bone tool and click the top bone in the bone chain at the farthest right.

Bones

.The small bone in the inner right chain is parented to the top bone in the far right chain.

Play the animation back. You’ll notice that when the animation reaches Frame 24, where the reparenting took place, there is a sudden change in the angle of the bone that was reparented in the chain on the left side. This is due to the mathematics in the physics because it’s getting a sudden surge of springy action.

You don’t see this effect on the chain on the right side because it is isolated by the small bone that was assigned as the parent. In this case, the small bone gets a the sudden change in angle, but it isolates that change from the bones in the inner right bone chain.

Moho 12

This tutorial introduces another type of layer in Moho: Image Layers. Image layers are a way of including artwork created in other programs in a Moho project. Any application that can produce image files can be used with Moho: photo editors, 3D modeling programs, natural media painting programs, the list goes on...

An image layer in Moho contains a single image file that can be used as a

background, or combined with a bone layer to build a character. Although they’re called Image layers, an Image layer can also make use of a movie file as its source.

Image layers and vector layers can be mixed and matched in the same project.

Alpha Channels

You’ll notice that the images used in this tutorial do not appear rectangular. This is because they make use of an alpha channel to mark some parts of the image as transparent. We recommend using PNG images with Moho because they support full alpha channel transparency. You’ll need to use an image editing program (like Adobe Photoshop) to create images with transparency.

Start With a Sample File

For this tutorial, we’ll start with a project file that’s almost finished. It’s named Tutorial 4.1 and it’s located in the Tutorials > 4 - Images subfolder within your custom content folder.

Open the Tutorials > 4 - Images > Tutorial 4.1 file in Moho. This project is almost complete as it is. The only thing that’s missing is the dancer’s left hand.

9. Expand the Hula Girl layer in the Layers window, and you should see something like this:

Starting point for this tutorial