lattice (panel.3dscatter): how to make plot symbol thicker?

Dear Deepayan,

many thanks for answering.

Another thing I am wondering is the following: I know you can have (3d-like) "crosses" in the wireframe plot. But are there any other 3d-like plot symbols? Of course one can use different colors to distinguish between several points. The problem is that most of the scientific journals do not allow colors [or it's expensive]. I am thus wondering if the plot symbols have equivalent 3d-versions. It looks a bit odd to draw a 2d cross in a 3d wireframe. Or a circle. Concerning the circle, it could be a small ball in 3d for example. Is there anything like this?

No, at least not easily. The 3D crosses are done by mapping each point
into 3 perpendicular line segments, then projecting the endpoints into
the 2D space, and then joining them. This is hardcoded in
panel.3dscatter() -- search for the section inside 'if (cross)'. For
other 3D plotting characters, you need to replicate this process
(which is not really that difficult, but a bit tedious).

If you are going to be doing a lot of fancy 3D graphics, I would
strongly suggest considering rgl, which is a "real" 3D graphics
system. Proper 3D graphics are difficult in systems based on vector
graphics (like R graphics).

-Deepayan