Basic Concepts in 3ds Max - Part 2 - Rotations and Layers
In this tutorial, you cover the basic concepts of how rotations work in 3D. You also learn how to create a layering system to freeze and hide objects in your scene.
- Recorded in: 3ds Max 2013
- This tutorial is intended for use with 3ds Max version 2013 or higher.
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Before you start building the skeleton, it is important to cover some ground rules about rotations.
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There have been many papers about rotations in 3D, gimbal lock limitations, 90-degree and 180-degree flips and other related issues.
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Here we will not attempt to dissect all these problems that have already been addressed numerous times.
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Instead, you will follow a set of rules that will minimize the chance for such problems to occur.
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Understanding how rotations work in a 3D application makes it easier to decide which viewport to draw the bone branch in.
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As much as possible, you want to favor rotations on the Z-axis.
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For example, to build a leg or a spine, you'd want to use a side view like the Left view.
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This way, when you locally rotate the leg for example, the main rotation of the thigh or calf is happening on the Z-axis.
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You'd still need to animate the X and Y rotations,
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for the thigh mind you,
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the calf only rotates in Z,
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but these would represent secondary, less extreme motions.
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In the case of an arm, you would create the bones in the top view to favor the local rotation in Z again.
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The rotation in Y is only important at the shoulder level, since the forearm, like the calf, only rotates in local-Z.
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As far as the rotation in X is concerned, that effect is minimal.
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The reason for favoring the Z-axis is based on how rotations are evaluated in 3ds Max and in 3D software in general.
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The default order of rotational computations is XYZ.
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The final rotation is determined once all three axes have been evaluated.
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This means a change in X or Y affects all three axes, but a change in Z affects only that angle as it is evaluated last.
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Therefore, it is important that major rotations happen on that angle.
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You could potentially change the axis rotation order in the Motion panel.
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However, be aware that most gaming engines are only compatible with an XYZ Rotation Axis Order.
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It is often simpler to keep that a mind and make it a habit of favoring the Z-rotation axis when creating bones.
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This is precisely what you will do in the next movie.
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One last thing to consider before moving on; you may want to set up a layering system to help with scene management.
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This makes it easier to deal with hiding and freezing various objects.
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Right-click an empty area of the main toolbar and choose Layers. The Layers toolbar appears.
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Select all the components that make the zombie and choose the Create New Layer button on the Layers toolbar.
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Give your new layer a name such as "Mesh", ensure the Move Selection to New Layer option is enabled and click OK.
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A new layer is created and the zombie's visibility and Freeze status can now be controlled through this layer.
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If you don't want objects to show in gray when frozen, you would need to remove that option in the objects' properties.
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Deselect all objects in the viewport and create two new layers named "Controllers"
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You will use those as you start building the rig in the next movie.