Python Code for Camera Animation¶

Here are two python scripts to do camera animation: animation.py, and CameraMotion_rotate.py.

animations.py:

import visit, sys
import CameraMotion_rotate

def camera_orbit_z(focus, parallelScale):
  # rotation views:
  nrotviews = 5
  #view normal and up vector list:

  rotviews = []


  rotviews += [(0.0, 1.0, 0.0)]
  rotviews += [(1.0, 0.0, 0.0)]

  rotviews += [(1, 0, 0)]
  rotviews += [(0, -1, 0)]

  rotviews += [(0, -1, 0)]
  rotviews += [(-1, 0, 0)]

  rotviews += [(-1, 0, 0)]
  rotviews += [(0,  1, 0)]

  rotviews += [(0.0, 1.0, 0.0)]
  rotviews += [(1.0, 0.0, 0.0)]


  CameraMotion_rotate.rotate(focus, parallelScale, nrotviews, rotviews, 1)

CameraMotion_rotate.py:

# in rotation, assume focus and parallelScale don't change
def rotate(focus, parallelScale, nviews, views, direction):
  #
  # Create the control points for the views.
  cpts=[]

  for i in range(nviews):
      v=View3DAttributes()

      # print i, "of", nviews
      # print v

      if direction>0:
          v.viewNormal = views[i*2]
          v.viewUp = views[i*2+1]
      else:
          v.viewNormal = views[(nviews-1-i)*2]
          v.viewUp = views[(nviews-1-i)*2+1]

      v.focus = focus #(450, 575, 850)
      v.viewAngle = 30
      v.parallelScale = parallelScale #1120.55
      v.nearPlane = -2 * parallelScale #-2241.09
      v.farPlane = 2*parallelScale #2241.09
      v.imageZoom = 1.0
      v.imagePan = (0, 0)
      v.perspective = 1

      cpts = cpts + [v]

  # Create a tuple of camera values and x values. The x values are weights
  # that help to determine where in [0,1] the control points occur.
  # cpts = (c0, c1, c2, c3, c4, c5, c6)
  x=[]
  for i in range(nviews):
      x = x + [float(i) / float(nviews-1)]

  # Animate the camera. Note that we use the new built-in EvalCubicSpline
  # function which takes a t value from [0,1] a tuple of t values and a tuple
  # of control points. In this case, the control points are View3DAttributes
  # objects that we are using to animate the camera but they can be any object
  # that supports +, * operators.
  nsteps = 100
  for i in range(nsteps):
      print i
      t = float(i) / float(nsteps - 1)
      c = EvalCubicSpline(t, x, cpts)

      c.focus = focus
      c.viewAngle = 30
      c.parallelScale = parallelScale #1120.55
      c.nearPlane = -2*parallelScale #-2241.09
      c.farPlane = 2*parallelScale #2241.09
      c.imageZoom = 1
      c.perspective = 1
      SetView3D(c)
      # print c

      DrawPlots()
      SaveWindow()

In main python code, two necessary things to add.

In the beginning, add this line:

import animations

At the end, before delete all plots and close the database, add this line:

animations.camera_orbit_z(focus, parallelScale)

focus and parallelScale are attributes of a visit View. For example:

c = View3DAttributes()
c.focus = (0, 0.75, 0)
c.parallelScale = 5.0