Note

This section is only a reference describing the function, please see the chapter on mlab: Python scripting for 3D plotting for an introduction to mlab and how to interact with and assemble the functions of mlab.

Please see the section on Running mlab scripts for instructions on running the examples.

# Camera handling functions¶

## move¶

mayavi.mlab.move(forward=None, right=None, up=None)

Translates the camera and focal point together.

The arguments specify the relative distance to translate the camera and focal point, so as to produce the appearance of moving the camera without changing the effective field of view. If called with no arguments, the function returns the absolute position of the camera and focal point on a cartesian coordinate system.

Note that the arguments specify relative motion, although the return value with no arguments is in an absolute coordinate system.

Keyword arguments:

Forward:

float, optional. The distance in space to translate the camera forward (if positive) or backward (if negative)

Right:

float, optional. The distance in space to translate the camera to the right (if positive) or left (if negative)

Up:

float, optional. The distance in space to translate the camera up (if positive) or down (if negative)

Returns:

If no arguments are supplied (or all are None), returns a tuple (camera_position, focal_point_position)

otherwise, returns None

Examples:

Get the current camera position:

```>>> cam,foc = move()
>>> cam
array([-0.06317079, -0.52849738, -1.68316389])
>>> foc
array([ 1.25909623,  0.15692708, -0.37576693])
```

Translate the camera:

```>>> move(3,-1,-1.2)
>>> move()
(array([ 2.93682921, -1.52849738, -2.88316389]),
array([ 4.25909623, -0.84307292, -1.57576693]))
```

```>>> move(-3,1,1.2)
>>> move()
(array([-0.06317079, -0.52849738, -1.68316389]),
array([ 1.25909623,  0.15692708, -0.37576693]))
```

Mlab.yaw:

yaw the camera (tilt left-right)

Mlab.pitch:

pitch the camera (tilt up-down)

Mlab.roll:

control the absolute roll angle of the camera

Mlab.view:

set the camera position relative to the focal point instead of in absolute space

## pitch¶

mayavi.mlab.pitch(degrees)

Rotates the camera about the axis corresponding to the “right” direction of the current view. Note that this will change the location of the focal point (although not the camera location).

This angle is relative to the current direction - the angle is NOT an absolute angle in a fixed coordinate system.

Mlab.yaw:

relative rotation about the “up” direction

Mlab.roll:

absolute roll angle (i.e. “up” direction)

Mlab.move:

relative translation of the camera and focal point

## roll¶

mayavi.mlab.roll(roll=None, figure=None)

Sets or returns the absolute roll angle of the camera.

Mlab.view:

control the position and direction of the camera

## view¶

mayavi.mlab.view(azimuth=None, elevation=None, distance=None, focalpoint=None, roll=None, reset_roll=True, figure=None)

Sets/Gets the view point for the camera:

```view(azimuth=None, elevation=None, distance=None, focalpoint=None,
roll=None, reset_roll=True, figure=None)
```

If called with no arguments this returns the current view of the camera. To understand how this function works imagine the surface of a sphere centered around the visualization. The azimuth argument specifies the angle “phi” on the x-y plane which varies from 0-360 degrees. The elevation argument specifies the angle “theta” from the z axis and varies from 0-180 degrees. The distance argument is the radius of the sphere and the focalpoint, the center of the sphere.

Note that if the elevation is close to zero or 180, then the azimuth angle refers to the amount of rotation of a standard x-y plot with respect to the x-axis. Thus, specifying `view(0,0)` will give you a typical x-y plot with x varying from left to right and y from bottom to top.

Keyword arguments:

azimuth:

float, optional. The azimuthal angle (in degrees, 0-360), i.e. the angle subtended by the position vector on a sphere projected on to the x-y plane with the x-axis.

elevation:

float, optional. The zenith angle (in degrees, 0-180), i.e. the angle subtended by the position vector and the z-axis.

distance:

float or ‘auto’, optional. A positive floating point number representing the distance from the focal point to place the camera. New in Mayavi 3.4.0: if ‘auto’ is passed, the distance is computed to have a best fit of objects in the frame.

focalpoint:

array_like or ‘auto’, optional. An array of 3 floating point numbers representing the focal point of the camera. New in Mayavi 3.4.0: if ‘auto’ is passed, the focal point is positioned at the center of all objects in the scene.

roll:

float, optional Controls the roll, ie the rotation of the camera around its axis.

reset_roll:

boolean, optional. If True, and ‘roll’ is not specified, the roll orientation of the camera is reset.

figure:

The Mayavi figure to operate on. If None is passed, the current one is used.

Returns:

If no arguments are supplied it returns a tuple of 4 values `(azimuth, elevation, distance, focalpoint)`, representing the current view. Note that these can be used later on to set the view.

If arguments are supplied it returns None.

Examples:

Get the current view:

``` >>> v = view()
>>> v
(45.0, 45.0, 25.02794981, array([ 0.01118028,  0.        ,  4.00558996]))
```

Set the view in different ways:

```>>> view(45, 45)
>>> view(240, 120)
>>> view(distance=20)
>>> view(focalpoint=(0,0,9))
```

Set the view to that saved in v above:

```>>> view(*v)
```

Mlab.roll:

control the roll angle of the camera, ie the direction pointing up

## yaw¶

mayavi.mlab.yaw(degrees)

Rotates the camera about the axis corresponding to the “up” direction of the current view. Note that this will change the location of the focal point (although not the camera location).

This angle is relative to the current direction - the angle is NOT an absolute angle in a fixed coordinate system.