** SUBSTRUCTURE GENERATION FILE FOR substrframe_rotz201.inp
*NODE
 1 ,-4., -4., 2.4
11 , 4., -4., 2.4
*NGEN
1,11
*ELEMENT,TYPE=B31,ELSET=BEAM
1,1,2
*ELGEN,ELSET=BEAM
1,10
*BEAM SECTION,SECTION=RECT,MATERIAL=STEEL,ELSET=BEAM
0.1 , 0.1
0, -1.
3,3
*MATERIAL,NAME=STEEL
*ELASTIC
2.1E11 , 0.3
*DENSITY 
7200., 
**
**
*STEP
*SUBSTRUCTURE GENERATE,TYPE=Z201,MASS MATRIX=YES,OVERWRITE
*RETAINED NODAL DOFS
1 ,1,6
11,1,6
*SUBSTRUCTURE LOAD CASE, NAME=SNOW
*DLOAD
BEAM,PZ , 1.
*END STEP