diff --git a/docs/de.po b/docs/de.po
index 2de08a0db..f29b91d17 100644
--- a/docs/de.po
+++ b/docs/de.po
@@ -18634,9 +18634,6 @@ msgstr "Dieses Kommandozeilen-Programm dient zum Bearbeiten von Gruppendateien.
 #~ msgid "Fragile"
 #~ msgstr "Fragile"
 
-#~ msgid "ConstructTo"
-#~ msgstr "ConstructTo"
-
 #~ msgid "CheckSlide"
 #~ msgstr "CheckSlide"
 
diff --git a/docs/sdk/definition/defcore.xml b/docs/sdk/definition/defcore.xml
index d4a4a4601..93e2085ce 100644
--- a/docs/sdk/definition/defcore.xml
+++ b/docs/sdk/definition/defcore.xml
@@ -145,11 +145,6 @@
           <col>Integer</col>
           <col>0 or 1. Determines whether the object can be built.</col>
         </row>
-        <row>
-          <literal_col>ConstructTo</literal_col>
-          <col>C4ID</col>
-          <col>Definition change upon building.</col>
-        </row>
         <row>
           <literal_col>GrabPutGet</literal_col>
           <col>Integer</col>
diff --git a/planet/System.ocg/GetXVal.c b/planet/System.ocg/GetXVal.c
index 1cd242787..1a0249a09 100644
--- a/planet/System.ocg/GetXVal.c
+++ b/planet/System.ocg/GetXVal.c
@@ -32,7 +32,6 @@ global func GetDefFireTop()     { return GetDefCoreVal("FireTop", "DefCore"); }
 global func GetDefLine()        { return GetDefCoreVal("Line", "DefCore"); }
 global func GetDefCrewMember()  { return GetDefCoreVal("CrewMember", "DefCore"); }
 global func GetDefConstruction(){ return GetDefCoreVal("Construction", "DefCore"); }
-global func GetDefConstructTo() { return GetDefCoreVal("ConstructTo", "DefCore"); }
 global func GetDefGrab()        { return GetDefCoreVal("Grab", "DefCore"); }
 global func GetDefGrabPutGet()  { return GetDefCoreVal("GrabPutGet", "DefCore"); }
 global func GetDefRotate()      { return GetDefCoreVal("Rotate", "DefCore"); }
diff --git a/src/object/C4Def.cpp b/src/object/C4Def.cpp
index 61abc892c..5d8442e70 100644
--- a/src/object/C4Def.cpp
+++ b/src/object/C4Def.cpp
@@ -100,7 +100,6 @@ void C4Def::DefaultDefCore()
 	TopFace.Default();
 	Component.Default();
 	BurnTurnTo=C4ID::None;
-	BuildTurnTo=C4ID::None;
 	GrowthType=0;
 	CrewMember=0;
 	NativeCrew=0;
@@ -238,7 +237,6 @@ void C4Def::CompileFunc(StdCompiler *pComp)
 	pComp->Value(mkNamingAdapt(CrewMember,                    "CrewMember",         0                 ));
 	pComp->Value(mkNamingAdapt(NativeCrew,                    "NoStandardCrew",     0                 ));
 	pComp->Value(mkNamingAdapt(Constructable,                 "Construction",       0                 ));
-	pComp->Value(mkNamingAdapt(BuildTurnTo,                   "ConstructTo",        C4ID::None        ));
 
 	const StdBitfieldEntry<int32_t> GrabPutGetTypes[] =
 	{
diff --git a/src/object/C4Def.h b/src/object/C4Def.h
index ce7415ffa..3b8c53dd7 100644
--- a/src/object/C4Def.h
+++ b/src/object/C4Def.h
@@ -112,7 +112,6 @@ public:
 	C4TargetRect TopFace;
 	C4IDList Component;
 	C4ID BurnTurnTo;
-	C4ID BuildTurnTo;
 	int32_t GrowthType;
 	int32_t CrewMember;
 	int32_t NativeCrew;