> For the complete documentation index, see [llms.txt](https://scripting.karamba3d.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://scripting.karamba3d.com/2.-scripting-with-karamba3d-inside-grasshopper/2.8-the-python-3-component/2.8.4-how-to-modify-structural-models/2.8.4.2-activation-and-deactivation-of-elements.md).

# 2.8.4.2: Activation and Deactivation of Elements

The equivalent Python 3 code of the example in [section 2.4.2](/2.-scripting-with-karamba3d-inside-grasshopper/2.4-how-to-modify-structural-models/2.4.2-activation-and-deactivation-of-elements.md) looks like this:

{% code lineNumbers="true" %}

```
import Karamba.Models
import Karamba.CrossSections
import Karamba.Elements
import Karamba.Results
import KarambaCommon
from Karamba.Elements.States.Selectors import StateElement1DSelectorIndex
from Karamba.Geometry import *
from System.Collections.Generic import List
from System import String

model = Model_in
if not isinstance(model, Karamba.Models.Model):
      raise Exception("The input in 'Model_in' is not of type Karamba.Models.Model!")

# load case to consider for elimination of elements
lcName = "LC0";
lcNames = List[String]([lcName])
# get load-case combination
success, lcc = model.lcActivation.TryGetLoadCaseCombination(lcName)
# select load case 0 of load-case combination "LC0"
stateSelector = StateElement1DSelectorIndex(model, lcc, 0);

# clone the model and its list of elements to avoid side effects
model = model.Clone();
# clone its elements to avoid side effects
model.cloneElements();

k3d = KarambaCommon.Toolkit()

# do the iteration and remove elements with tensile axial forces
for iter in range(maxiter):
    # create a deform and response object for calculating and retrieving results
    model, max_disp, outForce, outEnergy, Warning = k3d.Algorithms.Analyze(model, lcNames)

    # check the normal force of each element and deactivate those under tension
    has_changed = False;
    for elem in model.elems:
        # retrieve resultant cross section forces
        N, V, M = elem.resultantCroSecForces(model, stateSelector, 0.3, 3)

        # check whether normal force is tensile
        if (N > 0):
            # set element inactive
            elem.set_is_active(model, False)
            has_changed = True

    # leave iteration loop if nothing changed
    if not has_changed:
        break

    # rebuild the C++ model
    model.buildFEModel()

# update model to its final state
model, max_disp, outForce, outEnergy, Warning = k3d.Algorithms.Analyze(model, lcNames)

# set up list of true/false values that corresponds to the elemment states
elem_activity = []
for elem in model.elems:
    elem_activity.append(elem.IsActive);


isActive = elem_activity;
maxDisp = max_disp;
Model_out = Karamba.GHopper.Models.GH_Model(model)

print("Everything OK");
```

{% endcode %}

{% file src="/files/qfg6gIUmyrhEmhuXfNg2" %}


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