# ParametricPlot and ParametricPlot3D crash with subscript notation

Bug introduced in 11.0 and persisting through 11.2

In all previous versions of Mathematica, the following works perfectly well:

ParametricPlot[{Subscript[x,1] + Subscript[x,2], Subscript[x,1] - Subscript[x,2]},
{Subscript[x,1], 0, 1}, {Subscript[x,2], 0, 1}]


or...

ParametricPlot3D[{Subscript[x,1] + Subscript[x,2], Subscript[x,1] - Subscript[x,2], 0},
{Subscript[x, 1], 0, 1}, {Subscript[x, 2], 0, 1}]


But as of v11.0, both ParametricPlot and ParametricPlot3D will cause the kernel to crash when using subscripted variables. This problem seems to exist at least on both Mac and Windows. I am not sure if it affects other plotting functions: certainly, Plot3D is working fine :)

One temporary fix is to remove the subscript notation as per:

ParametricPlot[ {x1 + x2, x1 - x2}, {x1, 0, 1}, {x2, 0, 1}]
ParametricPlot3D[ {x1 + x2, x1 - x2, 0}, {x1, 0, 1}, {x2, 0, 1}]


... which seems to be a 'workaround'.

Is anyone aware of other plotting functions not working correctly with Subscripts etc? The problem appears to be new to version v11.0.

Update: 9 July 2017 (rewards!)

• I get the same thing with 11.1.1 on Mac. Interesting, I didn't know that ParametricPlot could use two independent variables! – Chris K Jul 9 '17 at 8:16
• I can't speak to why it worked before and doesn't now, but "Avoid using subscripted symbols in your code" is usually given as general advice here: mathematica.stackexchange.com/questions/18393/… – hftf Sep 15 '17 at 20:29
• Please use the standard bug header, and do warn people about the kernel crash. I know you originally wrote that it fails in 11.1 and works in all previous versions, but I see the crash in 11.0 too, every time, so I changed this ... – Szabolcs Sep 15 '17 at 21:51