search for: rotationmatrix

Is there a way to change the viewpoint using view3d (or rgl.viewpoint) with respect to the image that currently appears rather than the perspective that rgl thinks is the default? For example, if I create an image and then perform what should be a no-op: rgl.viewpoint(userMatrix=rotationMatrix(0,1,0,0)) the image is rotated. Then I can perform rotations on the result without surprises. But I want to specify rotation with respect to the image as it originally appeared, or with respect to the viewpoint that is currently in effect. Experimentation has revealed that when using rotationMatr...

...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")

Hi all, How can I tell RGL to set the center for the rotation to the origin of the coordinate system (0,0,0). It seems that the default is to use the center of the display not the origin of the coordinate system. open3d() lines3d(c(0, 1), c(0,0), c(0,0)) lines3d(c(0,0), c(0, 1), c(0,0)) lines3d(c(0,0), c(0,0), c(0, 1)) TIA Mark ??????????????????????????????????????? Mark Heckmann Blog:

For a paper dealing with generalized ellipsoids, I want to illustrate in 3D an ellipsoid that is unbounded in one dimension, having the shape of an infinite cylinder along, say, z, but whose cross-section in (x,y) is an ellipse, say, given by the 2x2 matrix cov(x,y). I've looked at rgl:::cylinder3d, but don't see any way to make it accomplish this. Does anyone have any ideas? thx,