STAAD.Pro Supports

Instructions

Basic Supports

Fixed — restrains all 6 DOF:

fix_id = sup.CreateSupportFixed()

Pinned — translations restrained, rotations free:

pin_id = sup.CreateSupportPinned()

Fixed-But — selective releases or springs:

# releaseSpec: [FX,FY,FZ,MX,MY,MZ] → 0=fixed, 1=released, -1=spring
# springSpec: [KFX,KFY,KFZ,KMX,KMY,KMZ] → spring stiffness
sup_id = sup.CreateSupportFixedBut(
    ReleaseSpec=[0, -1, 0, 0, 0, 1],   # FY=spring, MZ=released
    SpringSpec=[0, 100.0, 0, 0, 0, 0]   # KFY=100
)

Inclined Supports

sup_id = sup.CreateInclinedSupport(
    inclinedType=2,   # 1=Pinned, 2=Fixed, 3=FixedBut
    refType=2,        # 0=distances, 1=coordinates, 2=node reference
    refNode=1,
    coord=[0, 0, 0],
    releaseSpec=[0,0,0,0,0,0],
    springSpec=[0,0,0,0,0,0]
)

Elastic Mat Support (Soil Springs)

Spring support distributed over tributary area. See [SUPPORT_CODES.md — Direction Codes](./assets/SUPPORT_CODES.md) for direction values and [SUPPORT_CODES.md — Spring Types](./assets/SUPPORT_CODES.md) for springType.

# Typical case: springs in Y direction (STAAD adds X/Z fixity for stability)
mat_id = sup.CreateElasticMat(
    direction=1,     # 1=Y Direction (use for most foundations)
    subgrade=20.0,   # kN/m^3 or equivalent
    printFlag=0,
    springType=0     # 0=Normal (bi-directional); 1=Compression only
)
sup.AssignSupportToEntityList(mat_id, [41, 42, 43])

# Y Only (direction=4): springs act ONLY in Y — use only when the model already
# has other supports (e.g. pinned/fixed nodes) providing X and Z restraint.
# Without those, the structure will be unstable in X/Z.

Plate Mat Support

pm_id = sup.CreatePlateMat(direction, subgrades, printFlag, springType)

Elastic Footing

foot_id = sup.CreateElasticFooting(length, width, direction, subgrade)

Assigning Supports

• sup.AssignSupportToNode(nodeID, supportID) — assigns to a SINGLE node
• Use a for loop to assign to multiple nodes

Workflow

1. Use execute_code to call staad.Geometry.GetNodeCount() and confirm the model has nodes
2. After adding geometry in the same script, call SaveModel(True) before assigning supports (see staad-core for SaveModel vs UpdateStructure)
3. Create support type once → assign to base nodes in a loop

Querying

Removing

sup.RemoveSupportFromNode([1, 2, 3])   # remove from nodes
sup.DeleteSupport(supportNo)            # delete definition
sup.RemoveElasticMatFromNode(nodeNo)     # remove elastic mat from node
sup.RemoveElasticMat(matId)              # delete elastic mat definition

Example

See assign-fixed-supports.py for a complete working example.

Gotchas

• AssignSupportToNode takes a SINGLE node ID — it does NOT accept a list; iterate with a loop
• Support methods (CreateSupportFixed, CreateSupportPinned, CreateSupportFixedBut, AssignSupportToNode, GetSupportNodes, GetSupportType, GetSupportInformation, DeleteSupport) raise on failure instead of returning a negative code — call them directly; execute_code reports any uncaught error
• When nodes were added in-memory in the same script, call SaveModel(True) before assigning supports — do NOT use UpdateStructure() (it discards unsaved geometry)
• For CreateSupportFixedBut: use -1 for spring DOFs (not 1); 1 = released, 0 = fixed, -1 = spring
• Compression-only supports (`springType=1`) are only compatible with plain linear static analysis — using them with P-Delta, Nonlinear, Buckling, or Cable analysis causes an engine error. The engine uses spring deactivation iterations that cannot coexist with those solver modes.