5
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I can't figure out why the following code only works with integers.

r1 = TransformedRegion[Cuboid[{-1, -1, -1}, {1, 1, 1}], TranslationTransform[{0, 1, 0}]]
RegionPlot3D[r1]
DiscretizeRegion[r1]
RegionQ[r1]

enter image description hereenter image description here

now, If I replace every "1" with a "1.", I get an error message.

r1 = TransformedRegion[Cuboid[{-1., -1., -1.}, {1., 1., 1.}], TranslationTransform[{0, 1,0}]]
RegionPlot3D[r1]
DiscretizeRegion[r1]
RegionQ[r1]

enter image description here

The problem seems to extend to most of mathematica's new region functions, as demonstrated below with RegionMeasure. A possible work around is to symbolically evaluate the expression first.

r1 = TransformedRegion[Cuboid[{-1., -1., -1.}, {1, 1, 1}],TranslationTransform[{0, 1, 0}]];
RegionMeasure[r1]

r1 = TransformedRegion[Cuboid[{-a, -a, -a}, {a, a, a}], TranslationTransform[{0, 1, 0}]];
RegionMeasure[r1] /. a -> 1.0

enter image description here enter image description here

Has anybody else experimented with this issue?

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  • $\begingroup$ Confirmed on Windows 7. $\endgroup$ – Simon Woods Aug 10 '14 at 19:33
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    $\begingroup$ RegionPlot is known to have problems with TransformedRegion. See this question. I suspect something similar is going on with RegionPlot3D. $\endgroup$ – m_goldberg Aug 11 '14 at 3:11
  • $\begingroup$ Confirmed on OS X 10.6.8. $\endgroup$ – m_goldberg Aug 11 '14 at 3:16
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    $\begingroup$ Confirmed on Windows 8.1. You should report this to WRI. $\endgroup$ – RunnyKine Aug 11 '14 at 4:31
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    $\begingroup$ I'm voting to close this question because this has been fixed in version 10.3.1 on Win7-64: output with 1.. $\endgroup$ – MarcoB Mar 1 '16 at 5:37

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