diff --git a/direct/src/interval/Interval.py b/direct/src/interval/Interval.py
index 218b04de39..b282ba8eac 100644
--- a/direct/src/interval/Interval.py
+++ b/direct/src/interval/Interval.py
@@ -19,7 +19,7 @@ class Interval(DirectObject):
         """__init__(name, duration, openEnded)
         """
         self.name = name
-        self.duration = duration
+        self.duration = max(duration, 0.0)
         self.state = CInterval.SInitial
         self.currT = 0.0
         self.doneEvent = None
@@ -37,8 +37,6 @@ class Interval(DirectObject):
         # if it should be ignored in this case.
         self.openEnded = openEnded
 
-        assert(self.duration >= 0)
-
     def getName(self):
         return self.name
 
diff --git a/direct/src/interval/cInterval.cxx b/direct/src/interval/cInterval.cxx
index db4ade6788..c58a5e9333 100644
--- a/direct/src/interval/cInterval.cxx
+++ b/direct/src/interval/cInterval.cxx
@@ -36,7 +36,7 @@ CInterval(const string &name, double duration, bool open_ended) :
   _state(S_initial),
   _curr_t(0.0),
   _name(name),
-  _duration(duration),
+  _duration(max(duration, 0.0)),
   _open_ended(open_ended),
   _dirty(false)
 {
@@ -53,7 +53,6 @@ CInterval(const string &name, double duration, bool open_ended) :
   _play_rate = 1.0;
   _do_loop = false;
   _loop_count = 0;
-  nassertv(_duration >= 0.0);
 }
 
 ////////////////////////////////////////////////////////////////////