# Animated sphere

I plotted an union of parametric curves in 3D (like a rollercoaster) and I want to create a solid sphere (radius of 0.5 approx.) that moves along the whole curve. You can do this in sage?

Animated sphere

4

For any animation, you should write a function to produce the successive frames. Something like the following, for example:

```
sage: var('t')
t
sage: c1=parametric_plot3d((t,0,0),(0,1),thickness=2)
sage: c2=parametric_plot3d((t,t^2,t^3),(0,1),thickness=2)
def frame(i):
return c1+c2+sphere(center=(i,i^2,i^3),size=.03,color='black')+sphere(center=(0,0,0),size=.03,color='black')
```

Then you can make a list of frames as

```
frames = [frame(i) for i in sxrange(0,1,.1)]
```

To animate them, use a modified version of @kcrisman 's answer to a similar question:

```
DATA = tmp_dir() # in the notebook, this will already be set to some temporary directory
for i in range(len(frames)):
saved[i].save(filename=DATA+'mypic%08d.png'%i)
os.system('cd '+DATA+'; convert -delay %s -loop %s *.png "Done.gif"'%(int(100),int(2)))
os.system('ls '+DATA)
```

Note that with the patch at Trac 12827 applied, you can use the `animate`

command directly:

```
A = animate(frames)
A.show()
```

For a longer animation or different format, saving the frames as separate images is probably better. The `convert`

utility from `ImageMagick`

works great for gifs, and `ffmpeg`

is good for other video formats.

Asked: **
2012-05-22 05:45:30 -0500
**

Seen: **564 times**

Last updated: **May 24 '12**

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Does http://ask.sagemath.org/question/1422/3d-animation-with-tachyon help? It's unclear whether the issue is making the spheres, or the technical aspect of making a 3d animation (which is not as seamless as it should be yet).

The issue is make de animation, I know how to plot a sphere in one point of the space, but I don't know how move the sphere along de curve. Thanks for answer!

Did the other one help? Otherwise put your exact code and ask again, and someone will probably be able to help.

No jajajaj I try to explain my project better. Approximately, I have this: c1=parametric_plot3d((t,0,0),(0,1)) c2=parametric_plot3d((t,t^2,t^3),(0,1)) s=sphere(center=(0,0,0),size=0.5,color='black') c1+c2+s This plot two curves and the sphere in (0,0,0), I want to move the sphere along these two curves. Also, kcrisman, thank you very much for the answers!!