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rgl package and animation

5 messages · Duncan Murdoch, Robert Baer

Original
Robert Baer
# 
I am trying to figure out how to use rgl package for animation.  It 
appears that this is done using the play3d() function.  Below I have 
some sample code that plots a 3D path and puts a sphere at the point 
farthest from the origin (which in this case also appears to be at the 
end of the path).  What I would like to do is animate the movement of 
another sphere along the length of the path while simultaneously 
rotating the viewport.

Duncan Murdock's (wonderful) Braided Knot YouTube video:
  (http://www.youtube.com/watch?v=prdZWQD7L5c)
makes it clear that such things can be done, but I am having trouble 
understanding how to construct the f(time) function that gets passed to 
play3d().  The demo(flag) example is a little helpful, but I still can't 
quite translate it to my problem.

Can anyone point to some some simple f(time) function examples that I 
could use for reference or give me a little hint as to how to construct 
f(time) for movement along the path while simultaneously rotating the 
viewport?

Thanks,

Rob



library(rgl)
# Generate a 3D path
dat <-
structure(list(X = c(0, 0.0618130000000008, 0.00223599999999635,
-0.0308069999999958, -0.172805999999994, -0.372467, -0.587706999999995,
-0.881484999999998, -1.103668, -1.366157, -1.625862, -1.94806699999999,
-2.265388, -2.68982699999999, -3.095001, -3.49749, -3.946068,
-4.395653, -4.772034, -5.111259, -5.410515, -5.649475, -5.73439,
-5.662201, -5.56714599999999, -5.39033499999999, -5.081581, -4.796631,
-4.496559, -4.457024, -4.459564, -4.641746, -4.84910599999999,
-5.08994300000001, -5.43129, -5.76372499999999, -6.199448, -6.517578,
-6.86423499999999, -6.90743999999999), Y = c(0, -0.100724, 
-0.169471999999999,
0.0365059999999886, -0.0929950000000019, -0.222977, -0.355759000000006,
-0.365822000000009, -0.329948999999999, -0.209557000000004, 
-0.0804140000000046,
0.0201339999999988, 0.295372, 0.138831999999994, 0.281104999999997,
0.223761999999994, 0.141905999999992, 0.0602949999999964, 
-0.0933080000000075,
-0.207596000000009, -0.328629000000006, -0.438568000000004, 
-0.469109000000003,
-0.623505000000009, -0.525467000000006, -0.568444, -0.638885999999999,
-0.727356, -1.073769, -1.03213500000001, -1.203461, -1.438637,
-1.65023100000001, -1.861351, -2.169083, -2.43147300000001, 
-2.69914300000001,
-2.961258, -3.23938000000001, -3.466103), Z = c(0, 0.13552900000002,
0.401062000000024, 1.21637000000004, 1.55395500000003, 1.73080500000003,
1.81167600000003, 2.18512000000004, 2.52603200000004, 3.03479000000004,
3.42654400000004, 3.82251000000002, 4.74490400000002, 4.644837,
5.41848800000002, 5.85867300000001, 6.37835699999999, 6.83395400000001,
7.216339, 7.59411600000004, 7.95590200000004, 8.352936, 8.70931999999999,
9.01669300000003, 9.48553500000003, 9.90005500000001, 10.397003,
10.932068, 11.025726, 12.334595, 13.177887, 13.741852, 14.61142,
15.351013, 16.161255, 16.932831, 17.897186, 18.826691, 19.776001,
20.735596), time = c(0, 0.0100000000000016, 0.0199999999999996,
0.0300000000000011, 0.0399999999999991, 0.0500000000000007, 
0.0600000000000023,
0.0700000000000003, 0.0800000000000018, 0.0899999999999999, 
0.100000000000001,
0.109999999999999, 0.120000000000001, 0.129999999999999, 0.140000000000001,
0.150000000000002, 0.16, 0.170000000000002, 0.18, 0.190000000000001,
0.199999999999999, 0.210000000000001, 0.220000000000002, 0.23,
0.240000000000002, 0.25, 0.260000000000002, 0.27, 0.280000000000001,
0.289999999999999, 0.300000000000001, 0.310000000000002, 0.32,
0.330000000000002, 0.34, 0.350000000000001, 0.359999999999999,
0.370000000000001, 0.379999999999999, 0.390000000000001)), .Names = c("X",
"Y", "Z", "time"), row.names = c("1844", "1845", "1846", "1847",
"1848", "1849", "1850", "1851", "1852", "1853", "1854", "1855",
"1856", "1857", "1858", "1859", "1860", "1861", "1862", "1863",
"1864", "1865", "1866", "1867", "1868", "1869", "1870", "1871",
"1872", "1873", "1874", "1875", "1876", "1877", "1878", "1879",
"1880", "1881", "1882", "1883"), class = "data.frame")


# Plot 3d path
with(dat, plot3d(X,Y,Z, type = 'l', col = 'blue', lty = 1))

# get absolute distance from origin
dat$r = sqrt(dat$X ^ 2 + dat$Y ^ 2 + dat$Z ^ 2)
mxpnt = dat[dat$r == mr,] # Coordinates of furthest point

# Plot a blue sphere at max distance
plot3d(mxpnt$X, mxpnt$Y, mxpnt$Z, type = 's', radius = 1, col = 'blue', 
add = TRUE)
Duncan Murdoch
#
On 12-11-02 7:47 PM, Robert Baer wrote:
Your code didn't include the mr variable, but I assume it's just 
max(dat$r).  With that assumption, I'd do the animation function as follows:

First, draw the new sphere at the first point and save the object id:

sphereid <- sphere3d(dat[1,c("X", "Y", "Z")], col="red", radius=1)

# Also save the spinner that you like:

spin <- spin3d( ) #maybe with different parms

# Now, the animation function:

f <- function(time) {
   par3d(skipRedraw = TRUE) # stops intermediate redraws
   on.exit(par3d(skipRedraw=FALSE)) # redraw at the end

   rgl.pop(id=sphereid) # delete the old sphere
   pt <- time %% 40 + 1 # compute which one to draw
   pnt <- dat[pt, c("X", "Y", "Z")] # maybe interpolate instead?
   sphereid <<- spheres3d(pnt, radius=1, col="red")
   spin(time)
}

Duncan Murdoch
Robert Baer
#
On 11/3/2012 6:47 AM, Duncan Murdoch wrote:
mr = max(dat$r)  # yes sorry, didn't get copied to original 
email code
Thanks so much Duncan!

I probably never would have gotten there without your help. (Especially 
since I had to look at the help for the <<- operator, which is 
conceptually a level beyond where I usually work).   It would be great 
to have an additional creative example or two for  f(time) functions in 
the play3d() help.  Your useful code comments really help me see what 
needs to happen in an f(time) function.

I really appreciate that you took the time to get me going!

Rob
Duncan Murdoch
#
On 12-11-03 11:40 AM, Robert Baer wrote:
I've made a small addition to the spin3d function and added an example 
to the ?spin3d page.  This isn't on CRAN yet, but you can get the latest 
from R-forge.  Make sure you get 0.92.898 or newer.

The new example shows a rotating view of spinning cubes, using the 
sprites3d function within the animation function.

Duncan Murdoch
1 day later
Robert Baer
# 
-- snip --
On 11/4/2012 7:45 AM, Duncan Murdoch wrote:
Thanks so much for taking the time to do this and for all the other 
contributions you make to the R community!

I should tell you that I also looked at your rgl function writeWebGL() 
over the weekend, and I think it holds tremendous potential for sharing 
visualizations of multidimensional data with a non-technical audience.  
Who knew it could be so easy to move three dimensional data from R to 
the web?

Rob Baer