There's no need to use $ in any form; F~(list1, list2) works fine.

@zenterix Maple's 2D plot command has some fairly sophisticated options (discont, fdiscont) for handling discontinuities. These can use both symbolic and numeric techniques, and I think better results are usually achieved symbolically. As far as I know, there's nothing like that currently available for 3D plots.

Larger grids generally provide "diminishing marginal returns". In other words, one quickly gets to a point where the plot's improvement isn't worth the additional computation. Using a 1000x1000 grid for this plot means 24-million numeric values computed, which is likely above your display's resolution. Maple's kernel can easily handle the initial computation of these, but the GUI has trouble moving and positioning them.

@acer As is usual with Maplesoft, the absence of any official response is quite disturbing. Even an official response just saying "We are aware of the existence of the problem. We are investigating. We will keep you updated." would be comforting. 

@acer FWIW, I did your suggested Options setting, and it seems that the problem has disappeared. So, I 🗳  👍 

@acer I vote up for this Answer also, and I'm surprised at how "tight" and unragged you managed to get it with the default grid values.

@Rouben Rostamian  It's an impressive work, Rouben. I wish that I could give this Answer a 2nd Vote Up.

Yes, it can be done. But before I tell you how, I'd like to know whether you want the prime to be used for all derivatives or only for those made with respect to a specific variable (of your choosing), such as x.

@vv I vote up. However, I'd change numpoints= n to grid= [i, j] in plot3d commands purely for pedagogical reasons. 

[This Comment is unrelated to your undefined issue.] Egads, does this mean that the default is now to show that ugly e warning every time e is used as a variable, even in 1D input? Can't that crap be reserved for the newbies using 2D Input?

@C_R I don't know much about MapleSim---so I don't know if this is relevant---but wouldn't the different moments of inertia between tori and cylinders be significant? I'd guess (just from visual observation) that "standard" train wheels are fairly close to cylinders of uniform density steel. But, for example, I'd suspect that bicycle wheels could be closely modeled by tori.

I suspect that degrees are not an allowed option when you have "system" set to "SI".

@Olesen From your description, especially the black screen part, this is almost certainly the same issue as is discussed in the Question that Preben provided a link to. So, there has been a plague of this just in the last few days.

@nm A weird thing is that this just started happening to me 2 days ago. And now it's happened 4 times. As you probably realize, I use Maple several hours per day, *every* day, for over 20 years.

And it's not only when the computer is coming back from "sleep"; it has happened while I was typing. 

This started happening yesterday for me (about 30 hours ago). I just had my 4th occurence a minute ago. My experience is exactly as you describe. I'm also using Windows 10. The behavior can also happen while on a help page.

@dharr Yes, here's a few possible corrections:

evalindets(sol, suffixed({_||(Z||(1, 2), B2)}), ()-> n)

or

evalindets(sol, suffixed({_||(Z1, Z2 ,B2)}), ()-> n)

or

evalindets(sol, suffixed({_Z1, _Z2, _B2}), ()-> n)