Unable to set script parameters using Quantity from ansys.units

[ThomasS-SS]

🔍 Before submitting the issue

• I have searched among the existing issues
• I am using a Python virtual environment

🐞 Description of the bug

i am trying to set script parameters in a discovery file using Quantity from ansys.units and it does not work. I read in the docu that values should be int or float, but to me, beeing able to pass values as quantities including units feels just natural. Therefore, i labeled the issue as bug/problem.

I would also be interested in a workaround. It seems, that i have to pass a length as meter. Is that always the case? Can i somehow get the required dimension from the modeler or design?

Trying to use Quantity anyway i get:
CRITICAL - - logger - handle_exception - Uncaught exception
Traceback (most recent call last):
File "", line 1, in
exec(open("script.py").read())
~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^
File "", line 22, in
File "<@beartype(ansys.geometry.core.designer.design.Design.set_parameter) at 0x256c41fc900>", line 13, in set_parameter
File "C:\Users\sld\pyEnvSimsam\Lib\site-packages\ansys\geometry\core\misc\checks.py", line 340, in wrapper
return method(self, *args, **kwargs)
File "C:\Users\sld\pyEnvSimsam\Lib\site-packages\ansys\geometry\core\designer\design.py", line 875, in set_parameter
response = self._grpc_client._services.driving_dimensions.set_parameter(
driving_dimension=dimension
)
File "C:\Users\sld\pyEnvSimsam\Lib\site-packages\ansys\geometry\core\errors.py", line 96, in wrapper
out = func(*args, **kwargs)
File "C:\Users\sld\pyEnvSimsam\Lib\site-packages\ansys\geometry\core_grpc_services\v0\driving_dimensions.py", line 76, in set_parameter
driving_dimension=from_driving_dimension_to_grpc_driving_dimension(
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
kwargs["driving_dimension"]
^^^^^^^^^^^^^^^^^^^^^^^^^^^
),
^
File "C:\Users\sld\pyEnvSimsam\Lib\site-packages\ansys\geometry\core_grpc_services\v0\conversions.py", line 1209, in from_driving_dimension_to_grpc_driving_dimension
return GRPCDrivingDimension(
id=driving_dimension.id,
...<2 lines>...
dimension_value=driving_dimension.dimension_value,
)
File "C:\Users\sld\pyEnvSimsam\Lib\site-packages\ansys\units\quantity.py", line 422, in float
raise ValueError(
"Cannot convert to a float as the Quantity is not dimensionless or a (solid) angle"
)
ValueError: Cannot convert to a float as the Quantity is not dimensionless or a (solid) angle

📝 Steps to reproduce

Please consider this script:

import ansys.geometry.core as pygeom
from ansys.units import Quantity

modeler = pygeom.launch_modeler_with_discovery(hidden=True)
modeler.open_file("Zylinder.dsco")
design = modeler.get_active_design()

# get all
dsc_pars = {}
for par in design.get_all_parameters():
print("parameter " + par.name)
dsc_pars[par.name] = par

# set some
radius = dsc_pars["radius"]
#radius.dimension_value = 0.01 # works and results in 10 mm in discovery
radius.dimension_value = Quantity(0.01, "m") # does not work

# communicate
for val in dsc_pars.values():
design.set_parameter(val)

and the embedded script of Zylinder.dsco:

# Python Script, API Version = V252
ClearAll()

# Kreis skizzieren
plane = Plane.PlaneXY
result = ViewHelper.SetSketchPlane(plane)
origin = Point2D.Create(MM(0), MM(0))
radius = Parameters.radius
result = SketchCircle.Create(origin, radius)

baseSel = SelectionPoint.Create(GetRootPart().DatumPlanes[0].Curves[0].GetChildren[ICurvePoint]()[0])
targetSel = SelectionPoint.Create(GetRootPart().DatumPlanes[0].GetChildren[IDatumPoint]()[0])

result = Constraint.CreateCoincident(baseSel, targetSel)
# EndBlock

# Volumenkörper aus Skizze bilden
mode = InteractionMode.Solid
result = ViewHelper.SetViewMode(mode, None)
# EndBlock

# 1 Fläche strecken
selection = FaceSelection.Create(GetRootPart().Bodies[0].Faces[0])
options = ExtrudeFaceOptions()
height = Parameters.height
result = ExtrudeFaces.Execute(selection, height, options)
# EndBlock

ans the script parameters:

💻 Which operating system are you using?

Windows

📀 Which ANSYS version are you using?

25R2

🐍 Which Python version are you using?

3.13

📦 Installed packages

ansys-api-dbu==0.3.28
ansys-api-discovery==1.0.14
ansys-api-fluent==0.3.36
ansys-api-geometry==0.4.89
ansys-api-platform-instancemanagement==1.1.3
ansys-api-tools-filetransfer==0.1.2
ansys-fluent-core==0.35.0
ansys-fluent-visualization==0.22.1
ansys-geometry-core==0.14.1
ansys-platform-instancemanagement==1.1.2
ansys-tools-common==0.3.1
ansys-tools-filetransfer==0.1.1
ansys-tools-path==0.8.1
ansys-units==0.9.1
appdirs==1.4.4
art==6.5
beartype==0.22.5
certifi==2025.10.5
charset-normalizer==3.4.4
click==8.3.0
colorama==0.4.6
contourpy==1.3.3
cycler==0.12.1
defusedxml==0.7.1
Deprecated==1.2.18
dirsync==2.2.6
docker==7.1.0
flexcache==0.3
flexparser==0.4
fonttools==4.60.1
geomdl==5.4.0
googleapis-common-protos==1.71.0
grpcio==1.76.0
grpcio-health-checking==1.62.3
grpcio-status==1.62.3
idna==3.11
importlib_metadata==8.7.0
Jinja2==3.1.6
joblib==1.5.2
kiwisolver==1.4.9
MarkupSafe==3.0.3
matplotlib==3.10.7
nltk==3.9.2
numpy==2.3.4
packaging==25.0
pandas==2.3.3
pillow==12.0.0
Pint==0.25.2
platformdirs==4.5.0
pooch==1.8.2
protobuf==4.25.8
pyansys-tools-report==0.8.2
pyparsing==3.2.5
python-dateutil==2.9.0.post0
pytz==2025.2
pyvista==0.46.4
pywin32==311
PyYAML==6.0.3
regex==2025.10.23
requests==2.32.5
scipy==1.16.3
scooby==0.10.2
semver==3.0.4
setuptools==80.9.0
six==1.17.0
tqdm==4.67.1
typing_extensions==4.15.0
tzdata==2025.2
urllib3==2.5.0
vtk==9.5.2
wrapt==1.17.3
zipp==3.23.0

[RobPasMue]

Hi @ThomasS-SS - let's read first through #1533 (comment)

As you can see, PyAnsys Geometry handles units in most scenarios. Those scenarios in which it might be missing (like driving dimensions) we will definitely work on it to make it available! However, the ansys-units library is not directly supported (although it works in a very similar fashion to pint). We might have to reconsider opening it again and adding support for this library.

[ThomasS-SS]

@RobPasMue thanks for the references. My solution for now is to rely on the DefaultUnitsClass

from ansys.geometry.core.misc.measurements import DEFAULT_UNITS
from pint import Quantity
q = Quantity(1,"m")
some_parameter.dimension_value = q.to(DEFAULT_UNITS.SERVER_LENGTH).magnitude

[RobPasMue]

Awesome, nicely implemented. This definitely shows that we need to expose the usage of quantities directly on assignment. Rather than having to do the magnitude conversion yourself. We will work on this shortly