diff --git a/tacs/caps2tacs/tacs_aim.py b/tacs/caps2tacs/tacs_aim.py
index 97be4ddf5..764298066 100644
--- a/tacs/caps2tacs/tacs_aim.py
+++ b/tacs/caps2tacs/tacs_aim.py
@@ -187,13 +187,14 @@ def setup_aim(
                 # link the egads aim to the tacs aim
                 self.aim.input["Mesh"].link(self._mesh_aim.aim.output["Surface_Mesh"])
 
-                # add the design variables to the DesignVariable and DesignVariableRelation properties
+                # Add the design variables to the DesignVariable and DesignVariableRelation properties
+                # for active variables only.
                 DV_dict = {}
-                if len(self.thickness_variables) > 0:
+                if len(self.active_thickness_variables) > 0:
                     self.aim.input.Design_Variable_Relation = {
                         dv.name: dv.DVR_dictionary
                         for dv in self._design_variables
-                        if isinstance(dv, ThicknessVariable)
+                        if isinstance(dv, ThicknessVariable) and dv._active
                     }
 
                     # register all thickness variables to each proc
@@ -268,10 +269,17 @@ def variables(self) -> List[ShapeVariable or ThicknessVariable]:
     def shape_variables(self) -> List[ShapeVariable]:
         return [dv for dv in self.variables if isinstance(dv, ShapeVariable)]
 
+    @property
+    def active_thickness_variables(self) -> List[ThicknessVariable]:
+        """
+        Return only active sorted thickness variables.
+        """
+        return [dv for dv in self.thickness_variables if dv._active]
+
     @property
     def thickness_variables(self) -> List[ThicknessVariable]:
         """
-        return sorted thickness vars so that the TACS derivatives can be appropriately obtained
+        Return sorted thickness vars so that the TACS derivatives can be appropriately obtained.
         """
         thick_var_names = [
             dv.name for dv in self.variables if isinstance(dv, ThicknessVariable)
@@ -362,13 +370,14 @@ def update_properties(self):
                     dv, ThicknessVariable
                 ):
                     if property.caps_group == dv.caps_group:
-                        property.membrane_thickness == dv.value
+                        property.membrane_thickness = dv.value
                         break
 
         # input new design var and property cards
-        self.aim.input.Design_Variable = {
-            dv.name: dv.DV_dictionary for dv in self._design_variables
-        }
+        if len([_ for _ in self._design_variables if _._active]) > 0:
+            self.aim.input.Design_Variable = {
+                dv.name: dv.DV_dictionary for dv in self._design_variables
+            }
         self.aim.input.Property = {
             prop.caps_group: prop.dictionary for prop in self._properties
         }
diff --git a/tacs/caps2tacs/tacs_model.py b/tacs/caps2tacs/tacs_model.py
index 384becf46..d47883bc7 100644
--- a/tacs/caps2tacs/tacs_model.py
+++ b/tacs/caps2tacs/tacs_model.py
@@ -281,8 +281,7 @@ def update_design(self, input_dict: dict = None):
                     changed_design = True
 
         # update thickness prop cards in t
-        if self.tacs_aim.change_shape:
-            self.tacs_aim.update_properties()
+        self.tacs_aim.update_properties()
 
         # record whether the design has changed & first analysis flag as well
         if self._first_analysis: