Clip

Description

Clip a grid (structured of unstructured) using a given clipping geometrical shape.

clip1 ==> clip2

Initial unstructured multi-element mesh on the left. Clipping with a plane on the right.

Parameters

  • base: antares.api.Base

    The input base to be clipped.

  • coordinates: list(str)

    The variable names that define the set of coordinates.

  • type: str, default= ‘plane’

    The type of geometrical shape used to clip. The values are: - plane - cone - cylinder - sphere - revolution

    If none of the above, you can also set a VTK functions as a value.

  • origin: tuple(float),

    The coordinates (tuple of 3 floats) of the origin used to define the clipping shape. Used for: - plane - cone - cylinder - sphere

  • normal: tuple(float),

    The coordinates (tuple of 3 floats) of the normal vector used to define a clipping plane.

  • angle: float,

    Angle (in radian) of the clipping cone.

  • radius: float,

    Radius of a clipping cylinder or sphere.

  • line: dict,

    Definition of the line for the clipping of type ‘revolution’.

    As an example, in a cylindrical coordinate system (x,r,t). Give the axial points as keys and radial points as values. The revolution will take place in the azimutal direction. The lowest and the greatest x-values will serve to set two x-constant clipping planes to only keep the domain in-between.

  • axis: str,

    The coordinate (name) that defines the clipping cone or cylinder.

  • invert: bool, default= False

    If True, invert the clipping domain.

  • memory_mode: bool, default= False

    If True, the initial base is deleted on the fly to limit memory usage.

  • with_families: bool, default= False

    If True, the output of the treatment contains rebuilt families based on the input base. All the families and all the levels of sub-families are rebuilt, but only attributes and Zone are transfered (not yet implemented for Boundary and Window).

Preconditions

Zones may be either structured or unstructured.

Zones may contain multiple instants.

Postconditions

The output base is always unstructured. 3D bases only contain tetrahedral elements. 2D bases only contain triangle elements. If with_families is enabled, the output base contains the reconstructed families of base.

Example

The following example shows a clipping with a plane defined with the point (0., 0., 0.) and the normal vector (1., 0., 0.).

import antares
myt = antares.Treatment('clip')
myt['base'] = base
myt['type'] = 'plane'
myt['origin'] = [0., 0., 0.]
myt['normal'] = [1., 0., 0.]
clipped = myt.execute()

Note

dependency on VTK

Main functions

class antares.treatment.TreatmentClip.TreatmentClip
execute()

Clip the geometry.

Returns

the unstructured Base obtained by clipping with a geometrical shape.

Return type

antares.api.Base

Example

"""
This example shows how to clip a base.

Note that even if the input base is structured, the output of the
clip treatment will be unstructured.
"""
import os

import antares

OUTPUT = 'OUTPUT'
if not os.path.isdir(OUTPUT):
    os.makedirs(OUTPUT)

# ------------------
# Reading the files
# ------------------
reader = antares.Reader('bin_tp')
reader['filename'] = os.path.join('..', 'data', 'ROTOR37', 'GENERIC', 'flow_<zone>_<instant>.dat')
ini_base = reader.read()

# -----------------------
# Clipping of type plane
# -----------------------
# For this clipping the dataset is cut by a plane and only the
# cells under the plane are kept (under/over is defined by the
# normal orientation).
# Note that the output dataset present a smooth plane cut at the
# clipping position
treatment = antares.Treatment('clip')
treatment['base'] = ini_base
treatment['type'] = 'plane'
treatment['origin'] = [70., 0., 0.]
treatment['normal'] = [1., 0., 0.]
result = treatment.execute()

# -------------------
# Writing the result
# -------------------
writer = antares.Writer('bin_tp')
writer['filename'] = os.path.join(OUTPUT, 'ex_clip_plane.plt')
writer['base'] = result
writer.dump()