3 first period of 3D model

[seddighi]

i have a 3D concrete one storey model. sections and element are elastic.
first time i have compute all translational mass and assigned to nodes, my first and second periods is okey. but my rotational period is almost zero.
mass 2 $M1 $b $M1 $b $b $b;
mass 10 $M1 $b $M1 $b $b $b;
mass 32 $M1 $b $M1 $b $b $b;
mass 40 $M1 $b $M1 $b $b $b;
mass 4 $M2 $b $M2 $b $b $b;
.
.

second time i just assign 2 translational mass and one mass moment to one nodes( my master Node) which is mass center also. but this time my first period is okey but 2 other periods are zero.
mass 101 $MT $b $MT $b $MR $b;

b is 1e-9
this is also my rigid diaphram command

fix 101 0 1 0 1 0 1; # 0 means constrainted

#----------define Rigid Diaphram, dof 2 is normal to floor
set perpDirn 2; # direction Y is prependecular to ZX plane
rigidDiaphragm $perpDirn 101 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40;
please help me.