I want to control a point in 3D graph by dragging it with the mouse lets say this is my code and I want to add some functionality like the way locator works in 2d graphics
Manipulate[ Graphics3D[{Black, PointSize[0.02], Point[pt]}, ImageSize -> Large, PlotRange -> {{-10, 10}, {-10, 10}, {-10, 10} }, Axes -> True], {{pt, {1, 1, 1}}, {-5, -5, -5}, {5, 5, 5},**Locator**}] Well, I wrote an interactive Variable Calculus book and, as I don't know a "3D locator", I used mouse events to select and drag points. I learned the code from several posts. Here I share tow basic examples
First one you can see in here. Second one follow
The code is
Manipulate[Grid[{ (*Titulos*) {Style["Puntos en 3D", Bold, 10,RGBColor[0.12, 0, 0.5]]}, { (*------------------------------------------ 3D --------------------*) DynamicModule[{pts={{2,0,2},{0,2,1}},index=0,pos0,pos1,mypr={{-2,4},{-2,4},{-2,4}},AV1Cap1Obj}, (*Objetos*) AV1Cap1Obj[var_]:=If[var==1,{Thickness[0.0001],Arrowheads[0.00], Arrow[ {{0,0,0},{0,0,0}} ] }, If[var==2,{PointSize[0.03], Point[Dynamic@pts[[2]]],FaceForm[],EdgeForm[], Cuboid[Dynamic[pts[[2]]-{0.5,0.5,0.5}]] } ] ]; (* *) EventHandler[ Graphics3D[{ AV0Cap1ejes, (*---------- Parte dinámica --------------*) Dynamic[{Text[,1.1pts[[2]],{0,-1}], Dashed, Thick, RGBColor[0, 0.3, 0], Gray, Line[{{pts[[2,1]],0,0},{pts[[2,1]],pts[[2,2]],0},{0,pts[[2,2]],0}}],Line[{{pts[[2,1]],pts[[2,2]],0},pts[[2]],{0,0,pts[[2,3]]}}], Text[Style[NumberForm[Round[pts[[2,1]],0.1],2],Bold,10],{pts[[2,1]],-0.4,0}], Text[Style[NumberForm[Round[pts[[2,2]],0.1],2],Bold,10],{-0.4,pts[[2,2]],0}],Text[Style[NumberForm[Round[pts[[2,3]],0.1],2],Bold,10],{0,-0.4,pts[[2,3]]}] }], MouseAppearance[EventHandler[ (*Función: Aplica # a {1,2,...}*) Mouseover[ { (*expr base, mouse fuera*) Dynamic[If[index===#,Red,RGBColor[0, 0.34, 0]]],AV1Cap1Obj[#] }, {(* mouse over*) Dynamic[If[index===0||index===#,Red,RGBColor[0, 0.34, 0]]],AV1Cap1Obj[#] } ](*MouseOver*), {"MouseDown":>(index=#;pos0=pts[[index]]) (*Selecciona: pos0 = posición actual*) }, PassEventsUp->True]&/@Range[Length[pts]](*EventHandler local, #=1,2,....*),"Arrow"] } (*Opciones Graphics3D*) ,PlotRange->mypr,ImageSize->350, ViewPoint->{1,1, 0.6}, Boxed->False,ImagePadding->None,SphericalRegion->True](*Graphics3D*) ,{ (*Si arrastra...*) "MouseDragged":>If[index>0,((pos1=#[[2]]+Projection[pos0-#[[2]],#[[1]]-#[[2]]])&@MousePosition["Graphics3DBoxIntercepts"]); pts[[index]]=pos1 ], (*Clip puntos*) "MouseUp":>(pts[[All,3]]=Clip[pts[[All,3]],{-1.8,2.8}];pts[[All,2]]=Clip[pts[[All,2]],{-1.8,2.8}];pts[[All,1]]=Clip[pts[[All,1]],{-1.8,2.8}]; index=0) }, (*Pass the events to LocatorPane by setting PassEventsDown\[Rule]True in the deepest event handlers*) PassEventsDown->True](*EventHandler Global*) ](*DynamicModule*) }}, Alignment->Top], (*Grid*) (*-------Manipulate------*) ContentSize ->Automatic, ControlPlacement->Top, AppearanceElements->None, Alignment->{Top}, SaveDefinitions->True, SynchronousInitialization->False, Initialization:>{ violeta=RGBColor[0.12, 0, 0.5]; Ejes3DTxy[xmin_,xmax_,ymin_,ymax_,zmin_,zmax_]:={ Black,Arrowheads[Medium], Arrow[Tube[{{xmin,0,0.01},{0,0,0.01},{xmax,0,0.01}},0.007]], Arrow[Tube[{{0,ymin+0.01,0.01},{0,0,0.01},{0,ymax+0.01,0.01}},0.007]], Arrow[Tube[{{0.01,0.01,zmin+0.01},{0.01,0.01,0.01},{0,0,zmax+0.01}},0.007]], Gray, Table[Line[{{IntegerPart[xmin],i,0},{IntegerPart[xmax],i,0}}],{i,IntegerPart[ymin],IntegerPart[ymax],1}],Table[Line[{{i,IntegerPart[ymin],0},{i,IntegerPart[ymax],0}}],{i,IntegerPart[xmin],IntegerPart[xmax],1}], }; AV0Cap1ejes=Ejes3DTxy[-1,3,-1,3,0,3]; wNformat[var_]:=Style[NumberForm[Round[ var ,0.1],3],Bold,12,RGBColor[0.23, 0, 0.70]]}] You can use ResourceFunction["Locator3D"] as follows:
Manipulate[ Graphics3D[ {Black, PointSize[0.02], ResourceFunction["Locator3D"][Dynamic@pt]}, ImageSize -> Medium, PlotRange -> {{-10, 10}, {-10, 10}, {-10, 10}}, Axes -> True ], {{pt, {1, 1, 1}}, None} ] 
Note how I set the control type of pt to None, and added the locator to the graphics myself. This is currently necessary, as Manipulate doesn't support custom "fancy" controls that merge with the content (effectively what is done for Locator). If you want to impose limits on the location of the locator, use the two-argument form of Dynamic (examples for how this works can also be seen in the documentation for Locator):
Manipulate[ Graphics3D[ {Black, PointSize[0.02], ResourceFunction["Locator3D"][ Dynamic[pt, (pt = Clip[#, {-5, 5}]& /@ #)&]] }, ImageSize -> Medium, PlotRange -> {{-10, 10}, {-10, 10}, {-10, 10}}, Axes -> True ], {{pt, {1, 1, 1}}, None} ] This resets the position to the allowed region before actually assigning it to pt.
Locator3D (see also the examples in the "Scope" section of the documentation). For reference, the default is something like {Black, Sphere[{0,0,0}, Scaled[0.05]]}. Note that you might also need to change the size of the handles (the colored arrows), this can be done using the ImageSize option (agian, see the examples in the documentation) $\endgroup$ ResourceFunction["Locator3D"] is all you need (you might need to update your local version using ResourceUpdate@ResourceFunction["Locator3D"]) $\endgroup$
ResourceFunction["Locator3D"]- it is intended to be a drop-in replacement forLocatorin 3D. (Apart from the fact that you can't use it as control type forManipilate) - I'll add a more concrete answer once I'm back at my PC $\endgroup$