diff --git a/eeschema/sim/sim_model_kibis.cpp b/eeschema/sim/sim_model_kibis.cpp
index 27c836f952..5ed3f44f73 100644
--- a/eeschema/sim/sim_model_kibis.cpp
+++ b/eeschema/sim/sim_model_kibis.cpp
@@ -110,10 +110,18 @@ std::string SPICE_GENERATOR_KIBIS::IbisDevice( const SPICE_ITEM& aItem, const PR
 
     KIBIS_PARAMETER kparams;
 
-    kparams.SetCornerFromString( kparams.m_supply, m_model.FindParam( "vcc" )->value->ToString() );
-    kparams.SetCornerFromString( kparams.m_Rpin, m_model.FindParam( "rpin" )->value->ToString() );
+    if ( m_model.FindParam( "vcc" ) )
+        kparams.SetCornerFromString( kparams.m_supply, m_model.FindParam( "vcc" )->value->ToString() );
+    
+    if ( m_model.FindParam( "rpin" ) )
+        kparams.SetCornerFromString( kparams.m_Rpin, m_model.FindParam( "rpin" )->value->ToString() );
+
+    if ( m_model.FindParam( "lpin" ) )
     kparams.SetCornerFromString( kparams.m_Lpin, m_model.FindParam( "lpin" )->value->ToString() );
+
+    if ( m_model.FindParam( "cpin" ) )
     kparams.SetCornerFromString( kparams.m_Cpin, m_model.FindParam( "cpin" )->value->ToString() );
+
     //kparams.SetCornerFromString( kparams.m_Ccomp, FindParam( "ccomp" )->value->ToString() );
 
     std::string result;
@@ -129,7 +137,10 @@ std::string SPICE_GENERATOR_KIBIS::IbisDevice( const SPICE_ITEM& aItem, const PR
 
     case SIM_MODEL::TYPE::KIBIS_DRIVER_DC:
     {
-        std::string paramValue = m_model.FindParam( "dc" )->value->ToString();
+        std::string paramValue = "";
+
+        if ( m_model.FindParam( "dc" ) )
+            paramValue = m_model.FindParam( "dc" )->value->ToString();
 
         if( paramValue == "hi-Z" )
         {
diff --git a/eeschema/sim/sim_model_r_pot.cpp b/eeschema/sim/sim_model_r_pot.cpp
index f7aac45358..bb0f9c2f9d 100644
--- a/eeschema/sim/sim_model_r_pot.cpp
+++ b/eeschema/sim/sim_model_r_pot.cpp
@@ -28,8 +28,14 @@
 
 std::string SPICE_GENERATOR_R_POT::ModelLine( const SPICE_ITEM& aItem ) const
 {
-    std::string r = m_model.FindParam( "r" )->value->ToSpiceString();
-    std::string position = m_model.FindParam( "pos" )->value->ToSpiceString();
+    std::string r = "0";
+    std::string position = "";
+    
+    if ( m_model.FindParam( "r" ) )
+        r = m_model.FindParam( "r" )->value->ToSpiceString();
+
+    if ( m_model.FindParam( "pos" ) )
+        position = m_model.FindParam( "pos" )->value->ToSpiceString();
 
     if( position != "" )
     {
diff --git a/eeschema/sim/sim_model_tline.cpp b/eeschema/sim/sim_model_tline.cpp
index 57d78b9506..ee14676c91 100644
--- a/eeschema/sim/sim_model_tline.cpp
+++ b/eeschema/sim/sim_model_tline.cpp
@@ -31,7 +31,7 @@ using PARAM = SIM_MODEL::PARAM;
 
 std::string SPICE_GENERATOR_TLINE::ModelLine( const SPICE_ITEM& aItem ) const
 {
-    std::string r, l, g, c, len;
+    std::string r="0" , l="0", g="0", c="0", len="1";
 
     switch( m_model.GetType() )
     {
@@ -50,15 +50,20 @@ std::string SPICE_GENERATOR_TLINE::ModelLine( const SPICE_ITEM& aItem ) const
         len = SIM_VALUE_FLOAT( 1 ).ToSpiceString();
         break;
     }
-
     case SIM_MODEL::TYPE::TLINE_RLGC:
-        r = m_model.FindParam( "r" )->value->ToSpiceString();
-        l = m_model.FindParam( "l" )->value->ToSpiceString();
-        g = m_model.FindParam( "g" )->value->ToSpiceString();
-        c = m_model.FindParam( "c" )->value->ToSpiceString();
-        len = m_model.FindParam( "len" )->value->ToSpiceString();
+    {
+        if( m_model.FindParam( "r" ) )
+            r = m_model.FindParam( "r" )->value->ToSpiceString();
+        if( m_model.FindParam( "l" ) )
+            l = m_model.FindParam( "l" )->value->ToSpiceString();
+        if( m_model.FindParam( "g" ) )
+            g = m_model.FindParam( "g" )->value->ToSpiceString();
+        if( m_model.FindParam( "c" ) )
+            c = m_model.FindParam( "c" )->value->ToSpiceString();
+        if( m_model.FindParam( "len" ) )
+            len = m_model.FindParam( "len" )->value->ToSpiceString();
         break;
-
+    }
     default:
         wxFAIL_MSG( "Unhandled SIM_MODEL type in SIM_MODEL_TLINE" );
         return "";