[R] rgl: axis/viewport/box problems in persp3d()

Marius Hofert m_hofert at web.de
Fri Sep 9 14:02:29 CEST 2011

Dear Duncan,

thanks for your quick response. 
Below is my second trial. I had to use mtext3d to place the label for the z-axis 
at the new axis where the ticks are drawn (if there's a simpler solution, please
let me know). Was the usage of rgl.viewpoint meant this way? It is nice to 
adjust the rotation of the plotted object by hand but then I want to make sure
the subsequent plot(s) have precisely the same rotation. 

Okay, great. 

One more thing I am wondering is: I tried to pass through arguments like
marklen or expand to rgl.bbox/bbox3d. Is anything like this possible? I would like
to change the length of the axis ticks.

Cheers & many thanks,


PS: I read somewhere that plotmath-expressions are not available in rgl. Is there
an update on this? I know it may be very difficult to implement this, I'm just 
wondering if there is an update/workaround on this (?)

s <- seq(0, 1, length.out=21)
M <- function(u) apply(u, 1, min)
u <- s
v <- s
z <- outer(u, v, function(u,v) M(cbind(u,v)))
persp3d(u, v, z, aspect="iso", front="line", lit=FALSE, axes=FALSE, xlab="", 
        ylab="", zlab="") 
axes3d(edges=c('x--','y--','z+-')) # label the right axes
title3d(xlab="x", ylab="y", zlab="") # put in axes labels [z is wrong]
mtext3d("z", edge='z+-', line=2) # put in z-axis label by hand
par3d(windowRect=c(0,0,480,480), zoom=1.2) # use zoom to get everything on the viewport; then adjust rotation by hand
pl <- par3d(c("userMatrix", "zoom", "FOV")) # record for use in other plots
rgl.postscript("myplot.pdf", fmt="pdf") # print to file
rgl.viewpoint(zoom=pl$zoom, fov=pl$FOV, userMatrix=pl$userMatrix, interactive=FALSE) # set the viewpoint for the next plot to make sure it looks the same

On 2011-09-09, at 12:41 , Duncan Murdoch wrote:

> On 11-09-09 6:18 AM, Marius Hofert wrote:
>> Dear expeRts,
>> I am a new user of rgl, below is my first trial to plot a simple function in 3d.
>> I managed to put the axes in the right locations, but:
>> (1) The xlab, ylab, and zlab arguments are ignored; how can I put in axes labels?
> Those are documented on the axes3d page, but are arguments to title3d, not axes3d.  So add title3d(xlab="x", etc.
>> (2) Since I removed the axes in persp3d() the viewport is too small; is it possible
>>     to keep the size of the viewport?
> You can manually adjust it to your taste, then write down the value of par3d("zoom").  Later you can reproduce the resizing by calling par3d(zoom= <saved value> ).
>> (3) The box is not correctly drawn, there are two "holes", one in (0,0,1) and one
>>     in (1,1,0); how can I fix that?
> That happens because OpenGL has a limit on the range of depths that can be displayed, and the corners of the box have been adjusted to be too close or far.  This is arguably a bug in rgl, but it's sometimes a feature.
> What I'd suggest is that you don't use rgl.viewpoint, you just manually adjust the display as you like, without making it quite as extreme, then record the values of par3d(c("userMatrix", "zoom", "FOV")); those control the viewpoint.
> Duncan Murdoch
>> Cheers,
>> Marius
>> require(rgl)
>> s<- seq(0, 1, length.out=21)
>> M<- function(u) apply(u, 1, min)
>> u<- s
>> v<- s
>> z<- outer(u, v, function(u,v) M(cbind(u,v)))
>> persp3d(u, v, z, aspect="iso", front="line", lit=FALSE, axes=FALSE, xlab="",
>>         ylab="", zlab="")
>> axes3d(edges=c('x--','y--','z+-'), xlab="x", ylab="y", zlab="z")
>> par3d(windowRect=c(0,0,480,480))
>> R1<- rotationMatrix(-55*pi/180, 1,0,0)
>> R3<- rotationMatrix(50*pi/180, 0,0,1)
>> R<- R1 %*% R3
>> rgl.viewpoint(interactive=TRUE, userMatrix=R) # rotate
>> rgl.postscript("myplot.pdf", fmt="pdf")
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