the problem occurs in this sequence: 
BlockUser();
SetAllDistAnglMatesDriven();
foreach (ActuatorSensor element in elements)
{
   if (element.IsActuator)
   {
       Feature feat = GetFeatureFromPersID(element.PersistantID);
       Dimension dim = GetDimensionFromFeature(feat);
       SetDimensionDriving(dim);
   }
}

then i modify values of mates, in my code, those mates are the one with element.IsActuator == true. then i call
ReadWriteSensorValues(ref elements);
if the mate is a mate in the top level assembly document, the code works, but for mates from a subassembly of the top level assembly, my method GetValue reads always 0. i have no clue what the root of the problem is, chat gpt cant help, with chat gpt i tried to modify my method GetFeatureFromPersID such that GetObjectByPersistReference3 get called on the ModelDocExtension of the corresponding subassembly document, which does not fix the problem. 
here are my used methods:
using SolidWorks.Interop.sldworks;
using SolidWorks.Interop.swconst;
using System;
using System.Collections.Immutable;
using System.Linq;
//the following properties correspond all to the top level assembly document
private readonly ModelDoc2 _modelDoc;
private readonly AssemblyDoc _assemblyDoc;
private readonly ModelDocExtension _modelDocExtension;
private readonly ModelView _modelView;

private void BlockUser()
{
   _modelDoc.SetBlockingState((int)swBlockingStates_e.swFullBlock);
}

private void SetAllDistAnglMatesDriven()
//https://help.solidworks.com/2026/english/api/sldworksapi/Get_Mates_and_Mate_Entities_Example_CSharp.htm
//https://help.solidworks.com/2026/english/api/sldworksapi/Traverse_Assembly_at_Component_and_Feature_Levels_Using_Recursion_Example_CSharp.htm
{
   TraverseAssemblySubDocs(_assemblyDoc);

   //check the mate feature (correct type?, then set driven)
   void CheckFeature(Feature feature)
   //https://help.solidworks.com/2026/english/api/sldworksapi/SolidWorks.Interop.sldworks~SolidWorks.Interop.sldworks.IFeature_members.html
   {
       //https://help.solidworks.com/2026/english/api/sldworksapi/SolidWorks.Interop.sldworks~SolidWorks.Interop.sldworks.IFeature~GetTypeName2.html
       string type = feature.GetTypeName2();
       if (type == "MateLimitDistanceDim" || type == "MatePlanarAngleDim")
       {
           Dimension dim = GetDimensionFromFeature(feature);
           //https://help.solidworks.com/2026/English/api/sldworksapi/SolidWorks.Interop.sldworks~SolidWorks.Interop.sldworks.IDimension~DrivenState.html
           //https://help.solidworks.com/2026/English/api/swconst/SOLIDWORKS.Interop.swconst~SOLIDWORKS.Interop.swconst.swDimensionDrivenState_e.html
           dim.DrivenState = (int)swDimensionDrivenState_e.swDimensionDriven;
       }
   }

   //travers Mategroup subfeatures in Assembly doc
   void CheckAssembly(ModelDoc2 doc)
   //https://help.solidworks.com/2026/english/api/sldworksapi/SolidWorks.Interop.sldworks~SolidWorks.Interop.sldworks.IModelDoc2_members.html
   {
       //https://help.solidworks.com/2026/english/api/sldworksapi/SolidWorks.Interop.sldworks~SolidWorks.Interop.sldworks.IFeatureManager_members.html
       //https://help.solidworks.com/2026/english/api/sldworksapi/SolidWorks.Interop.sldworks~SolidWorks.Interop.sldworks.IModelDoc2~FeatureManager.html
       FeatureManager featureManager = doc.FeatureManager;
       //https://help.solidworks.com/2026/english/api/sldworksapi/SolidWorks.Interop.sldworks~SolidWorks.Interop.sldworks.IFeature_members.html
       //https://help.solidworks.com/2026/english/api/sldworksapi/SolidWorks.Interop.sldworks~SolidWorks.Interop.sldworks.IFeatureManager~GetFeatures.html
       object[] features = featureManager.GetFeatures(false);
       foreach (var currentFeature in features)
       {
           CheckFeature((Feature)currentFeature);
       }
   }

   //find subassamblies recursive
   void TraverseAssemblySubDocs(AssemblyDoc AssDoc)
   //source: https://help.solidworks.com/2026/english/api/sldworksapi/SolidWorks.Interop.sldworks~SolidWorks.Interop.sldworks.IAssemblyDoc_members.html
   {
       CheckAssembly((ModelDoc2)AssDoc);
       //https://help.solidworks.com/2026/english/api/sldworksapi/SolidWorks.Interop.sldworks~SolidWorks.Interop.sldworks.IComponent2_members.html
       //https://help.solidworks.com/2026/english/api/sldworksapi/SolidWorks.Interop.sldworks~SolidWorks.Interop.sldworks.IAssemblyDoc~GetComponents.html
       object[] components = AssDoc.GetComponents(false);
       foreach (var currentObject in components)
       {
           ModelDoc2 currentDoc = null;
           Component2 currentComponent = (Component2)currentObject;
           //https://help.solidworks.com/2026/english/api/sldworksapi/SolidWorks.Interop.sldworks~SolidWorks.Interop.sldworks.IComponent2~GetModelDoc2.html
           if (currentComponent != null) currentDoc = currentComponent.GetModelDoc2();

           AssemblyDoc currentAssDoc = null;
           if (currentDoc != null)
           {
               try
               {
                   currentAssDoc = (AssemblyDoc)currentDoc;
               }
               catch (Exception)
               {
                   //skip, because currentDoc is not an assembly
               }
           }

           //continue recursive search
           if (currentAssDoc != null) TraverseAssemblySubDocs(currentAssDoc);
       }
   }
}

private Mate2 GetMateFromFeature(Feature feature)
{
   //https://help.solidworks.com/2026/english/api/sldworksapi/SolidWorks.Interop.sldworks~SolidWorks.Interop.sldworks.IFeature~GetSpecificFeature2.html
   return (Mate2)feature.GetSpecificFeature2();
}

private Dimension GetDimensionFromFeature(Feature feature)
//correct mate type not garanteed, call CheckMateType
{
   //https://help.solidworks.com/2026/english/api/sldworksapi/SolidWorks.Interop.sldworks~SolidWorks.Interop.sldworks.IFeature~GetSpecificFeature2.html
   Mate2 mate = (Mate2)feature.GetSpecificFeature2();
   //https://help.solidworks.com/2026/English/api/sldworksapi/SolidWorks.Interop.sldworks~SolidWorks.Interop.sldworks.IDisplayDimension_members.html
   //https://help.solidworks.com/2026/English/api/sldworksapi/SolidWorks.Interop.sldworks~SolidWorks.Interop.sldworks.IMate2~DisplayDimension2.html
   //only gear has DisplayDimension2[1]
   DisplayDimension displayDimension = mate.DisplayDimension2[0] ?? throw new NullReferenceException("DisplayDimension");

   //https://help.solidworks.com/2026/English/api/sldworksapi/SolidWorks.Interop.sldworks~SolidWorks.Interop.sldworks.IDimension_members.html
   //https://help.solidworks.com/2026/English/api/sldworksapi/SOLIDWORKS.Interop.sldworks~SOLIDWORKS.Interop.sldworks.IDisplayDimension~GetDimension2.html
   //If the display dimension is not a chamfer display dimension, then Index is ignored. 
   Dimension dimension = displayDimension.GetDimension2(0) ?? throw new NullReferenceException("Dimension");
   return dimension;
}

private Feature GetFeatureFromPersID(ImmutableArray pid)
{
   if (pid.IsDefaultOrEmpty)
       throw new ArgumentException("pid is empty.", nameof(pid));

   int ok = (int)swPersistReferencedObjectStates_e.swPersistReferencedObject_Ok;

   byte[] pidBytes = pid.ToArray();

   // Helper: try resolve against a ModelDocExtension, return Feature or throw/return null
   Feature TryResolveOnModelDocExtension(ModelDocExtension ext, out int errorCode)
   {
       if (ext == null)
       {
           errorCode = (int)swPersistReferencedObjectStates_e.swPersistReferencedObject_Invalid; // arbitrary
           return null;
       }

       object resolved = ext.GetObjectByPersistReference3(pidBytes, out errorCode);
       if (errorCode == ok && resolved is Feature feature)
           return feature;
       return null;
   }

   // 1) Try top-level doc first (fast path)
   {
       Feature fTop = TryResolveOnModelDocExtension(_modelDocExtension, out int topErr);
       if (fTop != null) return fTop;
       // not found at top-level; continue searching components
   }

   // 2) Recursively traverse components in the top-level assembly and try each component's ModelDocExtension.
   //    Use only loaded ModelDoc2 instances; if GetModelDoc2() returns null for a component, skip it (we throw detailed exc later if nothing found).
   int lastError = -1;

   Feature TryResolveInComponent(Component2 comp)
   {
       if (comp == null) return null;

       // Try component's own ModelDoc2 (the component's document instance)
       try
       {
           ModelDoc2 compModel = null;
           try { compModel = comp.GetModelDoc2(); } catch { compModel = null; }

           if (compModel != null)
           {
               ModelDocExtension compExt = null;
               try { compExt = compModel.Extension; } catch { compExt = null; }

               if (compExt != null)
               {
                   Feature f = TryResolveOnModelDocExtension(compExt, out int err);
                   lastError = err;
                   if (f != null) return f;
               }
           }
       }
       catch
       {
           // swallow and continue to children — we will surface useful error if nothing found
       }

       // If not found, recursively try children components (if any)
       try
       {
           // Component2.GetChildren() commonly returns an object[] of Component2; handle defensively.
           object childrenObj = null;
           try { childrenObj = comp.GetChildren(); } catch { childrenObj = null; }

           if (childrenObj is object[] childrenArr)
           {
               foreach (object childRaw in childrenArr)
               {
                   Component2 childComp = childRaw as Component2;
                   if (childComp == null) continue;
                   Feature fromChild = TryResolveInComponent(childComp);
                   if (fromChild != null) return fromChild;
               }
           }
           else if (childrenObj != null)
           {
               // if not array, attempt to handle single child
               Component2 single = childrenObj as Component2;
               if (single != null)
               {
                   Feature f = TryResolveInComponent(single);
                   if (f != null) return f;
               }
           }
       }
       catch
       {
           // ignore and continue
       }

       return null;
   }

   // Get top-level components from the AssemblyDoc.
   // Try common GetComponents signatures defensively.
   bool triedTopComponents = false;
   try
   {
       object compsObj = null;
       try { compsObj = _assemblyDoc.GetComponents(false); } catch { compsObj = null; } // try false (all components)
       if (compsObj == null)
       {
           try { compsObj = _assemblyDoc.GetComponents(true); } catch { compsObj = null; } // fallback: top-level only
       }

       if (compsObj is object[] compsArr)
       {
           triedTopComponents = true;
           foreach (object compRaw in compsArr)
           {
               Component2 comp = compRaw as Component2;
               if (comp == null) continue;
               Feature found = TryResolveInComponent(comp);
               if (found != null) return found;
           }
       }
       else if (compsObj is Component2 singleComp)
       {
           triedTopComponents = true;
           Feature found = TryResolveInComponent(singleComp);
           if (found != null) return found;
       }
   }
   catch
   {
       // swallow; we'll throw below if not found
   }

   // If we get here nothing resolved. Build a helpful exception message.
   string msg;
   if (!triedTopComponents)
   {
       msg = "Could not enumerate components from top-level assembly (GetComponents returned null or threw).";
   }
   else
   {
       msg = lastError == ok
           ? "PID was not found in any loaded sub-model's ModelDocExtension."
           : \\\$"PID was not found in any loaded sub-model. Last GetObjectByPersistReference3 error code: {lastError}.";
   }

   throw new Exception(\\\$"Failed to resolve PID across assembly: {msg}");
}

 private void SetDimensionDriving(Dimension dim)
{
    dim.DrivenState = (int)swDimensionDrivenState_e.swDimensionDriving;
}
private void ReadWriteSensorValues(ref ImmutableArray elements)
{
   //if not rebuilt, the dimension dont update
   FullRebuid();
   foreach (ActuatorSensor element in elements)
   {
       Feature feat = GetFeatureFromPersID(element.PersistantID);
       Dimension dim = GetDimensionFromFeature(feat);
       ImmutableArray.Builder builder = element.SensorValues.ToBuilder();
       double val = GetValue(dim);
       builder.Add(val);
       element.SensorValues = builder.ToImmutableArray();
   }
}