# Why this “is not a correctly specified region”?

I want to subtract one Cuboid[] form another Cuboid[]. This is the code I use:

RegionPlot3D@ RegionDifference[Cuboid[{1, 1, 1}, {-1, -1, -1}],Cuboid[{0.5, 0.5, 0.5}, {-0.5, -0.5, -0.5}]]


but I get the error:

RegionDifference::reg: "Cuboid[{1,1,1},{-1,-1,-1}] is not a correctly specified region. "

On the other hand, the code:

RegionPlot3D@ RegionDifference[Cuboid[{1, 1, 1}],Cuboid[{0.5, 0.5, 0.5}]]


works:

Graphics3D and Show can visualize the two cube:

Show[Graphics3D[{Opacity[0.2],Cuboid[{0.5, 0.5, 0.5}, {-0.5, -0.5, -0.5}]}],
Graphics3D[{Opacity[0.2], Cuboid[{1, 1, 1}, {-1, -1, -1}]}]]


What am I doing wrong?

• Graphics3D can be forgiving but in general the first point should be a lower one. Not sure where exactly does it matter but I recall a question where lighting of cuboid was broken on MacOS due to that reversed spec, worked on Windows. – Kuba Aug 17 '18 at 11:32
• @Kuba that is a bug then, or do you see a rationale that will justify such restriction? – rhermans Aug 17 '18 at 14:48
• @rhermans it is the first line in Cuboid docs :) – Kuba Aug 17 '18 at 16:01

d = RegionDifference[Cuboid[{-1, -1, -1}, {1, 1, 1}],