Lesson 4: Adjusting muscle length

 
 
 

Muscles created with the Muscle Creator window have three built-in cross section curve sets that you can edit: one for the default rest position, one for the squash state, and another for the stretch state. You can directly edit these curves in the scene view, or using the Muscle Creator window. The following example shows you how to adjust the muscle length for each of these poses.

Open the scene for the lesson

  1. Load the Sabertooth_Length_Start.mb file from the Lesson 4 folder.

    This scene contains the saber tooth tiger with capsulated bones, a front leg muscle, and a neck muscle that has been set in all three pose states.

  2. Scrub frame by frame to see the neck muscle squash and stretch.

    Notice that the neck muscle travels down from the cervical joints to the humerus joint in a straight line, which causes the muscle surface to either stick out too much from the tiger’s body, or go through the shoulder joints. This not only looks unnatural, but it also affects how the muscle works. In the next steps, you will fix this by changing the muscle’s center line for each of its pose states so that it follows the contours of the tiger’s body.

Adjust the muscle length

In the following steps, you will use the muscle locators to adjust the muscle length for each of the pose states.

Adjust the rest locators

  1. Select Muscle > Muscles/Bones > Muscle Creator from the main menu.

    The Muscle Creator window opens.

  2. Go to frame 0, where the neck muscle is in a rest state.
  3. Select the neck muscle surface and switch to the Edit tab in the Muscle Creator.
  4. In the Attach Rest section, select AttachMidMus_L_Neck11.

    This selects the first inner wireframe box at the top of the neck muscle, which represents the attach point for the nearby cross section.

  5. Using the Move tool, adjust the position of the top part of the neck muscle so it goes around (instead of through) the cervical joint.
  6. Repeat the process with the remaining Attach Rest points until you’re satisfied with the results.

    The muscle shape should be organic and follow the tiger’s body. Don’t worry about placing the attach points perfectly, as you can always tweak them later.

Adjust the squash locators

  1. Go to frame 5, where the neck muscle is in a squash state.
  2. Adjust the center line for this state by selecting the attach points from the Attach Squash section of the Edit tab, and then reposition them using the Move tool.

Adjust the stretch locators

  1. Go to frame 17, where the neck muscle is in a stretch state.
  2. Select the attach points from the Attach Stretch section of the Edit tab, then reposition them using the Move tool so that the muscle goes around the shoulder before ending at the humerus.
  3. Scrub through the animation to view the effect of the changes you made.

Beyond the lesson

In this lesson you learned to adjust the muscle’s length by altering its center line. You can find the completed file for this lesson, Sabertooth_Length_End.mb, in the Maya Muscle Advanced Techniques folder. Now you are ready to sculpt the muscle surface.

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