Tool Palettes Construction > Plane > Options

### Construction > Plane

Creates a reference plane. You can set the construction plane from reference planes, or use them as input to tools that require a plane.

#### Reference planes and construction planes

The following tools are used to create a general-purpose plane which can be used as a reference plane or a construction plane:

A reference plane can be used with certain tools, including the Curve Edit > Curve planarize tool, Curve Edit > Curve section tool, and the Cross-Sections button in the Control Panel.

A construction plane allows you to temporarily use a separate coordinate system that can be arbitrarily oriented with respect to the world space coordinate system.

You can easily convert a reference plane to a construction plane and vice versa.

##### > Overview of construction planes

Tools in AliasStudio place objects in an XYZ coordinate system. Normally this is the world space coordinate system, the absolute frame of reference for the universe of your scene.

However, there will be times when you need to align objects in a specific context, where the orientation, position and rotation are different from those of the world space axes and origin.

In these cases, construction planes let you create and work in an alternative coordinate system that can be displaced and rotated from the world space coordinate system.

You can create construction planes that you position and rotate in relation to the world space coordinate system. These are useful when you are modeling objects that must have an absolute orientation that is not aligned with a major axis.

You can also create construction planes that you position and rotate in relation to a curve or surface. These are very powerful tools, and are useful in a wide variety of modeling contexts.

There can only be one construction plane in a scene (that is, the current construction plane). All other planes are referred to as reference planes. You can convert a reference plane to a construction plane (and vice versa) at any time. You can also use reference planes with certain tools (Curve Planarize tool, Curve Section tool, and the Cross-Sections button in the Control Panel).

##### > Example

For example, consider the curve below. We want to create a surface perpendicular to the curve at its end.

In world space this would be difficult: we would have to draw construction curves for the new surface, then try to rotate the construction curves to be perpendicular to the tangent at the end of the curve.

With construction planes, the task is much easier. With curve snapping on, we snap the new construction plane to the curve and slide it to the end.

Now we can draw the curves for the new surface much more easily. The grid is perpendicular to the end of the original curve, and the origin of the new coordinate system is the original curve's endpoint.

Finally we use the Toggle Construction Plane tool to return to the world space coordinate system. The new construction curve is exactly perpendicular to the endpoint of the original curve. Now we can use Set planar or other surface building tool.

##### > Construction planes and the Perspective window

When a construction plane is active, placement in the perspective window is constrained to the construction plane. This includes:

• Drawing curves.
• Creating primitive objects.
• Moving objects.

#### To create a reference plane or construction plane

1. Click the Plane icon, or choose Construction > Plane from the Palette.
2. Click in a view window to place the origin of the plane.
• Click in empty space or type a 3D coordinate to place the plane origin exactly.
• Click a curve to constrain the plane origin to the curve.
• Click an isoparametric curve on a surface to constrain the plane origin to the surface.
• Click a reference point to use it as the plane origin.
• Click a reference vector to align the plane with it.
3. To set the orientation of the plane do one of the following:
• Click in a view window or type a 3D coordinate to set the plane's Z-axis direction, and then click again in a view window to set another point on the plane.
• Click Accept Points and use the manipulator handles to move, rotate, and size the plane.
• Click a reference point to set the plane's Z-axis direction, and then click in a view window to set another point on the plane.
• Click a curve to constrain the plane's Z-axis to the curve, and then click in a view window to set another point on the plane.
• Click an isoparametric curve on a surface to constrain the plane's Z-axis to the surface, and then click in a view window to set another point on the plane.
• If you constrained the plane origin to a curve or surface, the plane will be tangent to the curve/surface.
• If you constrained the plane origin to a curve or surface, you can click Surf./Free to toggle the manipulator orientation from worldspace (Free) to curve/surface parameter space (Surf.).
• To accept the current orientation of the plane, click Accept Points.
4. To create a reference plane, click Next Plane.
5. To create a construction plane, click Set Construction Plane.

There can only be one construction plane in a scene. If you create a construction plane and there is already a construction plane in the scene, the existing construction plane will become a reference plane.

#### To use the plane manipulator

Click a handle to select it (the handle becomes white), then either:

• Drag the handle to move/rotate/scale the plane. (See details below.)
• Type exact values on the keyboard.
• Click on geometry or the grid, while using a snap mode, to snap the manipulator's axes to a specific position or orientation.
##### > Interactive manipulation
• Drag an arrow handle to move the plane along an axis.

• Drag a dotted arc to rotate the plane around the axis with the same color (the axis perpendicular to the arc).

• Drag a square handle to scale the plane along the axis that has the same color as the square.

• Click an arrow handle to change the center handle to the free move handle. Then drag the center handle to move the plane freely.

• Click a sphere or arc handle to change the center handle to the free rotate handle. Then drag the center handle to rotate the plane freely around all three axes (or around the normal for a plane constrained to a surface).
• Click one of the rectangular boxes to flip the plane to one of the two perpendicular orientations.

• Click a dotted axis line to reflect the plane across the X, Y, or Z axes.

• Use Edit > Undo to undo changes to the manipulator.

#### To edit the current reference/construction plane

1. Select a reference/construction plane.
2. Click the Construction > Plane tool.
3. If you created the plane by specifying three points, then the three points are displayed for the selected plane. You can adjust the position of each point by dragging it.

If you created the plane using the manipulator, then the manipulator reappears on the selected plane. The coordinate system is toggled back to world space.

You can also select the Plane tool first, then select the plane you want to edit.

Open the Information window (Windows > Information > Information window ) to see detailed information as you manipulate the plane.

#### To delete a reference/construction plane

1. Pick only the reference/construction plane.
2. Press the Delete key, or choose Delete > Delete active from the menus.

#### Mouse buttons in construction planes

You can choose between the following mouse behaviors when using Transform > Move in a perspective window with an active construction plane:

• Three dimensional (default):
• moves along plane's X
• moves along plane's Y
• moves along plane's Z

or

• Planar:
• moves freely across plane's X and Y
• moves along plane's X
• moves along plane's Y

To change between the two control schemes, choose Preferences > General Preferences  , go to the Input section, and set the Mouse mapping for perspective move: On construction plane option.

#### Tips

You can easily snap to a curve that intersects a construction plane, and position the snap point either anywhere along the curve, or precisely at the point where the curve and plane intersect. When you drag the snap point close to the construction plane, a yellow cross appears on the plane indicating that the snap point is precisely at the intersection point.

#### Options

##### Show Name

Show the name of the plane next to it in the view window. This option is on by default.

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