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pyosis

Python client library for OSIS Bridge & Tunnel Analysis Platform (developed by CCCC Highway Consultants Co., Ltd.).

pyosis provides an object-oriented Python API for automating the creation of bridge/tunnel finite element models, executing analysis solvers, and extracting post-processing results.

Installation

Due to naming conflicts on PyPI, please install using:

pip install osis-python

If your mirror hasn't synced yet, use:

pip install osis-python -i https://pypi.org/simple

Requirements

• OSIS >= 5.0 (includes the required Python runtime environment)
• Python >= 3.8
• Solver-only mode additionally requires the solver distribution that ships PySolver.dll (e.g. D:\OSIS_Solver\Rbin64).

Quick Start

1. Using OSISEngine (Recommended)

OSISEngine is the core facade class of pyosis, integrating all module managers and providing a unified project-level entry point:

from pyosis.core.engine import OSISEngine

engine = OSISEngine()

# Clear project
engine.clear()

# Set global parameters
engine.control.set_gravity_acceleration(9.8066)
engine.control.set_calc_tendon(True)
engine.control.set_calc_creep(True)

# Create sections
sec = engine.section.create_circle(no=1, name="CircleSection", d=0.5)

# Create materials
mat = engine.material.create_conc(no=1, name="C30Concrete", code="JTG3362_2018", grade="C30")

# Create nodes
n1 = engine.node.create(no=1, x=0, y=0, z=0)
n2 = engine.node.create(no=2, x=15, y=0, z=0)

# Create elements
elem = engine.element.create_beam3d(
    no=1, node1=n1.no, node2=n2.no, nMat=mat.no, nSec1=sec.no, nSec2=sec.no
)

# Create boundaries
bd = engine.boundary.create_general(no=1, x=1, y=1, z=1, rx=1, ry=1, rz=1, rw=1)
bd.assign("a", [n1.no])

# Create load case and add loads
lc = engine.load.create("Self-weight", load_case_type="D")
lc.create_gravity()

# Solve
engine.solve()

2. Engine Convenience Methods

OSISEngine provides project-level convenience methods:

# Project management
engine.new_project()           # Create new project
engine.save_project()          # Save current project
engine.open_project(path)      # Open existing project

# Model information
summary = engine.model_summary()  # Returns dict with all manager counts

# Import/Export
engine.export_apdl(path)       # Export to APDL format
engine.import_apdl(path)       # Import from APDL format

# Result output for calculation book
engine.output_result_for_calc_book()

# Matrix output
engine.matrix("matrix_1", [[1, 2],[3, 4]])

3. Using Managers Directly

If you don't need the convenience methods of Engine, you can also import individual managers directly:

from pyosis.material import material_manager
from pyosis.node import node_manager

mat = material_manager.create_conc(no=1, name="C30", code="JTG3362_2018", grade="C30")
node = node_manager.create(0, 0, 0)

4. Using OSISSolver — Start the Solver Directly (Solver-Only Mode)

By default, OSISEngine() connects to an already-running OSIS GUI process. If you want to drive the solver without opening the GUI (e.g. for headless batch runs, CI, or server-side automation), use OSISSolver to load the solver DLL directly via ctypes and launch its HTTP server:

from pyosis.core.solver import OSISSolver
from pyosis.core.engine import OSISEngine

# Load <install>/PySolver.dll and start the HTTP server (default port 18080)
solver = OSISSolver(osis_install_path=r"D:\OSIS_Solver\Rbin64")
engine = OSISEngine.from_solver(solver)

# Create a project (type 101 = bridge analysis), then build the model as usual
engine.project.create(101, r"D:\work\my_bridge\my_bridge.sis")
engine.control.set_gravity_acceleration(9.8066)
# ... build sections / materials / nodes / elements ...
engine.solve()

Notes on solver-only mode:

• osis_install_path must be the directory containing PySolver.dll (and its dependency DLLs).
• The solver needs a project to exist before model commands run: call engine.project.create() / open() first.
• Crash minidumps are written to <install>\Error\dmp\ (created on startup).

Core Architecture

Manager System

pyosis adopts a Manager pattern to organize code. Each module corresponds to a Manager:

Sub-Managers

Some managers contain sub-managers, accessed via attributes:

# Element groups (create + add elements in one call)
engine.element.group.create("MainGirderElements", "c")            # create empty group
engine.element.group.create("MainGirderElements", "a", "1to3")    # add elements 1-3

# Boundary groups
engine.boundary.group.create("AbutmentBoundaries", "c")
engine.boundary.group.create("AbutmentBoundaries", "a", "1to2")

# Various boundary types
engine.boundary.create_general(no=1, x=1, y=1, z=1, rx=1, ry=1, rz=1, rw=1)           # General support
engine.boundary.create_master_slave(no=1, node=1, dx=1, dy=1, dz=1, rx=0, ry=1, rz=1, coincident=2)  # Master-slave
engine.boundary.create_rigid(no=1, nNodeI=1)                                               # Rigid link
engine.boundary.create_elstcspt(no=1, coor="", x=0, dx=1e9, y=0, dy=1e9, z=0, dz=1e9)     # Elastic support

# Tendons
prop = engine.tendon.prop.create_in(
    name="15-10", mat=3, code="GBT5224_2014",
    diameter=15.2, num=10, pipe=0.09,
)
shape = engine.tendon.shape.create_arc3d(
    name="N1", n_num=2, prop="15-10",
    element_group="MainGirderElements", curve_name="curve1"
)

# Live loads
grade = engine.live.grade.create(name="HighwayClassI", code="JTGD60_2015", type="HIGHWAY_I")
lane = engine.live.lane.create(name="Lane1", type="VE")
case = engine.live.case.create(name="LiveLoadCase 1", code="JTGD60_2015")

Display Control

# Show/hide boundaries, loads and tendons
engine.display.disp_ctrl("bc", "all", "all", 1)          # Show all boundaries
engine.display.disp_ctrl("lg", "nforce", "all", 0)       # Hide all concentrated forces
engine.display.disp_ctrl("td", "all", ["T1", "T2"], 1)   # Show specific tendons

# View orientation
engine.display.set_view("top")          # standard / top / right / front

# Display switch
engine.display.set_plsm(1)              # 0 = off, 1 = on

Property & Thickness Management

# Coordinate systems (三点定义)
engine.prop.coord.create_three_point(
    no=1, p1x=0, p1y=0, p1z=0,
    p2x=1, p2y=0, p2z=0,
    p3x=0, p3y=1, p3z=0,
)

# Creep and shrinkage(no, name, avg_humidity, birth_time, type_coeff, shrink_birth)
engine.prop.creep_shrink.create(no=1, name="Creep1", avg_humidity=70.0,
                                birth_time=7, type_coeff=5.0, shrink_birth=3)

# Damping (Rayleigh 自定义系数)
engine.prop.damping.create_rayleigh_custom(name="Damping1", alpha=0.05, beta=0.005)

# P-U curve (no, name, curve_type, num, values)
#   curve_type: 1=水平位移推力 2=竖向位移推力 3=竖向力位移
engine.prop.pu_curve.create(no=1, name="PU1", curve_type=1, num=3, values=[0, 0.01, 1000, 0.02, 1500])

# Element thickness assignment (thickness, op, *elems)
engine.prop.assign_component_thickness(thickness=0.3, op="a", elems=[1])

# Shell thickness (no, in_plane, out_plane)
engine.thickness.create(no=1, in_plane=0.3, out_plane=0.3)

Geometry Queries

The GeometryManager supports querying geometric entities:

# Get all splines
splines = engine.geometry.all("spline")

# Get a specific spline
spline = engine.geometry.get("spline", name="curve1")

# Filter by type
arcs = engine.geometry.filter("spline", spline_type="ARC3D")

Data Class Objects

Create and query operations return data class objects (dataclass) instead of raw dictionaries:

elem = engine.element.get(1)
print(elem.no)          # ID
print(elem.node_vec)    # Node list
print(elem.mat)         # Material ID

# Objects support operations (operations下沉 to object)
lc = engine.load.get("Self-weight")
lc.create_gravity()
lc.create_nforce(1, dFx=1000)

Explicit Numbering

Some create_* functions support explicit numbering via the no parameter. If not specified, the number is automatically assigned:

# Auto-assigned number
sec = engine.section.create_circle(name="Section1", d=0.5)

# Explicit number
sec = engine.section.create_circle(name="Section1", d=0.5, no=100)

Result Export

After solving, you can export various analysis results using engine.result. All export methods return pandas DataFrames:

# Export load case results (element forces)
df = engine.result.loadcase("Self-weight", "LCEF")

# Export envelope results (element forces)
df = engine.result.env("BasicCombinationEnvelope", "EnvEF")

# Export design check results
df = engine.result.check(
    "混凝土", "正截面抗弯验算", "基本组合"
)

# Batch export all check results from Check folder
results = engine.result.check_all()
for name, df in results.items():
    print(f"{name}: {len(df)} rows")

Supported result types:

• Load case: LCEF (element force), LCED (element displacement), LCND (node displacement), LCBF (boundary reaction), LCTL (tendon loss), LCS (element stress)
• Envelope: EnvBF (boundary reaction), EnvEF (element force), EnvES (element strain), EnvS (element stress), EnvND (node displacement)

Requires pandas to be installed: python -m install pandas

Complete Example

from pyosis.core.engine import OSISEngine

engine = OSISEngine()
engine.clear()

# Control parameters
engine.control.set_gravity_acceleration(9.8066)
engine.control.set_calc_tendon(True)
engine.control.set_calc_concurrent_force(True)
engine.control.set_calc_shrink(True)
engine.control.set_calc_creep(True)
engine.control.set_calc_shear(True)
engine.control.set_calc_relaxation(True)
engine.control.set_mod_loc_coor(False)
engine.control.set_inc_tendon(True)
engine.control.set_nonlinear(geom=False, link=False)

# Sections
engine.section.create_circle("CircleSection1", d=0.219, tw=0.012, no=1)
engine.section.create_circle("CircleSection2", d=0.180, tw=0.008, no=2)

# Materials
engine.material.create_steel(
    "Steel1", code="JTGD64_2015", grade="Q345", dmp=0.05, no=1
)

# Nodes
engine.node.create(0, 5, 0, no=1)
engine.node.create(15, 5, 0, no=2)
engine.node.create(7.5, 0, 0, no=3)
engine.node.create(20, 0, 0, no=4)

# Elements
engine.element.create_beam3d(1, 3, nMat=1, nSec1=1, nSec2=1, no=1)
engine.element.create_beam3d(2, 3, nMat=1, nSec1=2, nSec2=2, no=2)

# Boundaries
engine.boundary.create_general(no=1)
engine.boundary.get(1).assign("a", [1, 2])

# Loads
lc = engine.load.create(
    "CustomLoadCase1",
    load_case_type="USER",
    prompt="Two forces applied at nodes 3 and 4"
)
lc.create_nforce(3, dFx=0, dFy=-1000000, dFz=0)
lc.create_nforce(4, dFx=200000, dFy=0, dFz=0)

# Solve
engine.solve()

End-to-End Demo

See tests/pyosis_demo.py for a runnable end-to-end example that:

• Starts the solver directly via OSISSolver (no GUI required)
• Builds the 25m 简支小箱梁 example model (10 prep modules)
• Runs engine.solve()
• Exports LCND / LCEF / EnvND / EnvEF results to CSV

The demo reuses the prep modules from tests/output/output_py/25m简支小箱梁中梁-solveronly/, so it serves both as a smoke test and a copy-paste template.