# How can I make such drawings

This Fig. represents LQU, where LQU is a function of $$c_1,c_3$$, and $$c_3$$, $$c_i \in[-1,1]$$.

How can I make such drawings? • Depends on what "LQU" is. See Plot3D, RegionPlot3D, ParametricPlot3D – Bob Hanlon Sep 25 at 20:04
• What is LQU? and what c1,c3,ci means – cvgmt Sep 26 at 2:57

tet = Tetrahedron[{{-1, -1, -1}, {1, 1, -1}, {-1, 1, 1}, {1, -1, 1}}];

Graphics3D[{tet}, Axes -> True] We can use RegionPlot3D with the options Mesh and MeshShading to subdivide tet into 8 tetrahedra and style the faces differently:

SeedRandom

RegionPlot3D[tet,
PlotPoints -> 90, BaseStyle -> Opacity[.9],
Mesh -> 1,
MeshShading -> RandomColor[{2, 2, 2}] ,
Lighting -> "Neutral", Axes -> True] We can also use the function SymmetricSubdivision from Tetrahedron >> Applications to subdivide tet into 8 tetrahedra:

SymmetricSubdivision[Tetrahedron[pl_], k_] /; 0 <= k < 2^Length[pl] :=
Module[{n = Length[pl] - 1, i0, bl, pos},
i0 = DigitCount[k, 2, 1]; bl = IntegerDigits[k, 2, n];
pos = FoldList[If[#2 == 0, #1 + {0, 1}, #1 + {1, 0}] &, {0, i0},  Reverse[bl]];
Tetrahedron @ Map[Mean, Extract[pl, #] & /@ Map[{#} &, pos + 1, {2}]]]

colors = {Yellow, Yellow, Blue, Yellow, Blue, Blue, Blue, Yellow};

Graphics3D[{colors[[# + 1]], SymmetricSubdivision[tet, #]} & /@
Range[0, 7], BaseStyle -> Opacity[0.5], Axes -> True] 