@Christopher2222 To answer the open questions out there:

1)   When I tried Maplet, I still got no visible output.

2)   I have version 17.01 and am using Windows 8.

3)   The color plot option did not help nor did thickness.   I set thickness = 3 and color = black and there was still no visible output.

4)  There is no problem with lines in the plane, only in space.  

5)  Linestyle = solid (or dash or any of the other choices) fixes the problem or, rather, gets around the problem.   Am I the only user reporting this? 

      Thank you all for your help.

           David

@Alejandro Jakubi I tried all of Alejandro's test and the data structure was indeed properly created and the plotsetup(char) command produced the correct output.  However, the plot was still blank.  

   However: I have found the solution.   If I include a "linestyle" plot option within the line command, it works properly.   I can choose solid or dash or whatever and it works but if I leave that plot option out, as I would normally do, it fails to plot anything.   In the plane, there is no such issue but in space this is what I have discovered.  

In other words: line([0,0,0],[1,1,1]) produces no visible output but line([0,0,0],[1,1,1],linestyle=solid) does. In the plane line([0,0],[1,1]) works without the plot option of choosing a line style.

   Is this a bug or a feature?   Can it be fixed?

   Thank you all for your help so far.

@dholtzman I am 100% certain that this is an environment issue, not a coding issue.   I have written code to produce a tetrahedron with an inscribed sphere.   The Maple worksheet is on my flash drive so I know that it is not a typing issue.   When I execute the program on any machine available to me, it works perfectly except one machine, the one with Maple 17 and Windows 8.    In this case only the inscribed sphere shows up but not the tetrahedron made by 6 LINE commands which connect the 4 vertices in 3-space (thus, I know that it is not an orientation issue).

@Christopher2222 I tried rotating and nothing worked.   When I run the same program on my other two machines, everrything is fine.

@Carl Love 

with(plots):

with(plottools):

a:=line([0,0,0],[1,1,1]):

display([a],axes=none);

Thank you, Longrob.   That worked perfectly!

The arrow command is a bit odd.  The parameters that follow base point and end point (body width, head width and ratio of head size to length) all seem to be relative values, not absolutes.  The third parameter clearly is a relative term but this is not what I mean.   If I were to create an arrow with:

a:=arrow([0,0],[0,5],.5,1,.5):

and display just this single plot structure, I would get a very big arrow.  If I were to create a second arrow with:

b:=arrow([100,0],[100,5],.5,1,

.5):

and then display both plot structures, I would get something else entirely.

Can you explain how this works?

On second thought, this is not an arrow issue, per se.  Placing the two small arrows far apart, as I have done, makes the entire "canvas" large and thus, the objects small.  A single arrow will live in a small environment and thus, look large.    This would be the case for any plot object. 

Am I right?

P.S.  exporting plots as eps files seems to produce much better results than the other file types.

   Thanks again.

           David S-H

Thank you, Longrob.   That worked perfectly!

The arrow command is a bit odd.  The parameters that follow base point and end point (body width, head width and ratio of head size to length) all seem to be relative values, not absolutes.  The third parameter clearly is a relative term but this is not what I mean.   If I were to create an arrow with:

a:=arrow([0,0],[0,5],.5,1,.5):

and display just this single plot structure, I would get a very big arrow.  If I were to create a second arrow with:

b:=arrow([100,0],[100,5],.5,1,

.5):

and then display both plot structures, I would get something else entirely.

Can you explain how this works?

On second thought, this is not an arrow issue, per se.  Placing the two small arrows far apart, as I have done, makes the entire "canvas" large and thus, the objects small.  A single arrow will live in a small environment and thus, look large.    This would be the case for any plot object. 

Am I right?

P.S.  exporting plots as eps files seems to produce much better results than the other file types.

   Thanks again.

           David S-H

Hi Robert,

Thank you for your help.  I have fixed the typo and added a view constraint.  This gets rid of the error messages.  The plane generated by the implicit plot animates nicely.   I still can't get my space curves to show up.   I have two questions about what you have written. 

First, why do I need the sequence command?  When I input what you wrote, I got an error about one of my arguments being of the wrong type.

More to the point is the order of s=0..t and y=-6..6.  I have the y range first since for any fixed angle s, I want the space curve parametrized by y.   Now, in my proedure, I want to specify the range of angles.  Shouldn't that come second? 

Thanks again for your help.

David

Hi Robert,

Thank you for your help.  I have fixed the typo and added a view constraint.  This gets rid of the error messages.  The plane generated by the implicit plot animates nicely.   I still can't get my space curves to show up.   I have two questions about what you have written. 

First, why do I need the sequence command?  When I input what you wrote, I got an error about one of my arguments being of the wrong type.

More to the point is the order of s=0..t and y=-6..6.  I have the y range first since for any fixed angle s, I want the space curve parametrized by y.   Now, in my proedure, I want to specify the range of angles.  Shouldn't that come second? 

Thanks again for your help.

David

Thank you, Alex.  It worked nicely. 

David

Thanks, Alec.  How do I do that?  Do I right-click on the frame and select export?  Will animated gif be an option? 

Thanks, Alec.  How do I do that?  Do I right-click on the frame and select export?  Will animated gif be an option? 

Thank you, Robert.  It worked like a charm.

David

Thank you, Robert.  It worked like a charm.

David

Thanks, Robert.   I have since discovered that I can use F[1] in textplot but not in textplot3d.  Is there any way to make this work in 3d?

David