Node Normal Correction in Anura3D 2025 GiD Problem Type

[srinivas12viv]

Hi Anura3D Team,

In the context of applying node normal correction, particularly to handle sharp points in the geometry and assign accurate contact normals to avoid instabilities. I noticed a bug in the Anura3D 2025 GiD problem type.

Currently, the interface allows selecting node groups (e.g., normal_vector_1, normal_vector_2, etc.), but there is no option to specify the normal vector components, such as Normal X, Normal Y, and Normal Z (for 3D cases).

This capability appears to be missing from the ContactProperties XML definition. Additionally, the Tcl procedure Anura3D::WriteNormalVector in the createCPS script currently only writes node IDs to the CPS file. To enable full normal correction support, it should be updated to also write the specified normal vector for each node (e.g., nodeID nx ny [nz]). I would appreciate it if someone familiar with the GiD problem type structure could assist me in implementing these updates.

Currently, I have been manually editing the CPS file and using a .bat script to run the models with the correct input. However, it would be much more convenient if this functionality were integrated into the official problem type, allowing the models to be executed directly from within GiD.

Thank you

[srinivas12viv]

Never mind, I figured it out. ChatGPT was the savior here 😄. It just required a couple of modifications to the GiD problem type.

In the ContactProperties.xml file, I updated the definitions for all 10 normal vector conditions to include manual input fields for the vector components. For example:

  <condition n="normal_vector_1" pn="Normal vector 1" v="" state="hidden" ov="node" ovm="node" icon="elements.gif" help="Definition example: NodeID x y z (3D) or NodeID x y (2D)">
  <value n="nx" pn="Normal X" v="1.0" />
  <value n="ny" pn="Normal Y" v="0.0" />
  <value n="nz" pn="Normal Z" v="0.0" state="[check_dim 3D 3D:Axissymmetric %W]" />
  </condition>

Then, I modified the Tcl procedure Anura3D::WriteNormalVector inside scripts/createCPS to read and write both the node ID and the normal components to the CPS file. Here's the updated code

proc Anura3D::WriteNormalVector { stageNode i } {
   variable current_xml_root
   set value "normal_vector_$i"
   set xp_normvect [format_xpath {container[@n="Contact"]/condition[@n=%s]/group} $value]

   # Detect if problem is 3D
   set xp_dim {container[@n="General_data"]/value[@n="NDIM"]}
   set dim_typeNode [$current_xml_root selectNodes $xp_dim]
   set dim_type [$dim_typeNode @v]
   set is3D [expr {$dim_type == "3D" || $dim_type == "3D:Axissymmetric"}]

   set lines {}
   foreach gNode [$stageNode selectNodes $xp_normvect] {
       set groupName [$gNode @n]
       # Read nx, ny, nz from the group node (user-edited values)
       set nx [$gNode selectNodes {string(value[@n="nx"]/@v)}]
       set ny [$gNode selectNodes {string(value[@n="ny"]/@v)}]
       set nz ""
       if {$is3D} {
           set nz [$gNode selectNodes {string(value[@n="nz"]/@v)}]
       }
       # Get all node IDs in this group
       set nodeList [GiD_EntitiesGroups get $groupName node]
       foreach nodeId $nodeList {
           if {$is3D} {
               lappend lines [format "%s %s %s %s" $nodeId $nx $ny $nz]
           } else {
               lappend lines [format "%s %s %s" $nodeId $nx $ny]
           }
       }
   }
   if {[llength $lines]} {
       foreach line $lines {
           GiD_WriteCalculationFile puts $line
       }
   }
}
 
 

[hjk1108]

Hello, I'm also using contact attributes, may I ask which file you modified it?