Import Structures in Flac3D

Hello everyone,
Is it correct to import a surface then create a liner from it even if its mesh doesn’t correspond to the zones mesh ? The targets of link are zones, but I want to make sure if it is a correct method or shall I coincide the zones mesh to the surface mesh.

Thank you

Hello @Zakaria,
The liner nodes do not need to correspond with zone gridpoints. Links will automatically detect zone targets and distribute force, mass, stiffness etc. to the zones automatically based on weighting functions (i.e. were the end lands in the zone).

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Hi again @dblanksma
Could you please tell me if it is possible to change the liner nodes local system ? I see that struct.node.system.local — Itasca Software 9.0 documentation ( can only get the local system but not set it.
Are there any specific requirements or guidelines regarding the local system in relation to the surrounding zones?
One last question, while assigning a groupName to zones, gridpoints also get the groupName. Isn’t it the case for structure nodes ?
Thank you for your help.

Hello @Zakaria,
You can set the node local coordinate system with the command - structure node system-local
For one-sided liners here is how the orientation of the node-local coordinate system is defined in the online documentation:

The orientation of the node-local system for all nodes used by liner elements is set automatically at the start of a set of cycles (or when the model cycle 0 command is executed) such that the 𝑧-axis is aligned with the average normal direction of all liner elements using the node, and the 𝑥𝑦-axes are arbitrarily oriented in the liner element tangent plane

For two sided liners (also called embedded liners) the orientation of the node local coordinate system may not always be consistent and using the above command may be necessary.

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And for the grouping name inheritance. I believe structure nodes do inherit the same group name as their parent elements. But I could be wrong on this.

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Thank you @dblanksma