# Change timber material properties in gRPC

**URL:** <https://community.dlubal.com/t/change-timber-material-properties-in-grpc/3524>\
**Category:** API & Interfaces\
**Tags:** timber-design, material-properties, api-2\
**Created:** [May 15, 2026, 8:07pm UTC](https://community.dlubal.com/t/change-timber-material-properties-in-grpc/3524 "2026-05-15T20:07:40Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![marciosarto](https://community.dlubal.com/letter_avatar_proxy/v4/letter/m/edb3f5/32.png) [@marciosarto](https://community.dlubal.com/u/marciosarto)\
**Post date:** [May 15, 2026, 8:07pm UTC](https://community.dlubal.com/t/change-timber-material-properties-in-grpc/3524/1 "2026-05-15T20:07:40Z")

</div>

I am using gRPC to create timber material to be used in Timber Design.

However the API documentation is not clear in how I can modify specific timber parameters such as Strenght and Moduli properties in Material Values

 ![image](https://community.dlubal.com/uploads/default/original/2X/0/015544ffa8412ad086b2f1eb091198be6fcd4515.png)

It seems I need to edit properties in MaterialValuesTreeTable, but it is not clear which keys to use.

Can someone help me with that?

---

<div class="post-metadata">

**Author:** ![robert.milrath](https://community.dlubal.com/user_avatar/community.dlubal.com/robert.milrath/32/106_2.png) [@robert.milrath](https://community.dlubal.com/u/robert.milrath)\
**Post date:** [May 18, 2026, 8:49am UTC](https://community.dlubal.com/t/change-timber-material-properties-in-grpc/3524/3 "2026-05-18T08:49:00Z")

</div>

Hi marciosarto,

you'll find all needed informations in the documentation in the topic [Custom Material — Dlubal API documentation](https://apidocs.dlubal.com/source/rst_examples/rfem/modelling/custom_material.html).

```python
from dlubal.api import rfem, common

with rfem.Application() as rfem_app:

    material: rfem.structure_core.Material = rfem_app.get_object(
        rfem.structure_core.Material(
            no=1
        )
    )

    # IMPORTANT: get tree table and print to get the keys shown
    material_values_tree = material.material_values.rows[0].material_values_tree
    print(material_values_tree)

    common.set_values_by_key(
        tree=material_values_tree,
        key='e',
        values=[14500000000]
    )

    # Update material
    rfem_app.update_object(
        obj=rfem.structure_core.Material(
            no=1,
            user_defined=True,
            material_values=material.material_values,
        )
    )

```

I hope this helps.

Best regards  
Robert Milrath