dup obj

dup obj(id,id2)

        Duplicates the id1 object obj in the same type of id2 object.
dup light(1,2): Duplicates the light 1 to light 2.
dup vol(1,"vol2"): Duplicates the volume number 1 into the volume name vol2.

dup poi obj

dup poi obj(id)

        Duplicates points of the object obj id in the property poi dup.

dup poi(s) obj(id)

        Returns the pointssduplicated numbers of object obj obj(id).

dup poi(s) obj(id)=x1,y1,z1,x2,y2,z2

        Modifies duplicated points s.
dup poi vol(1); duplicates points of volume 1.
dup poi(5) vol(1); returns the duplicated point 5.
dup poi(5) vol(1)=100,-100,100; modifies the duplicated point 5.
np=NP vol(1);poi[1,np] vol(1)=dup poi[1,np] vol(1); gives the points of volume 1 duppliquées values 1. You can also do:
validate(1)vol(1);validate(-1)poi vol(1);