diff --git a/stim/biomodels/cellset.h b/stim/biomodels/cellset.h
index e922a0d..b7117f0 100644
--- a/stim/biomodels/cellset.h
+++ b/stim/biomodels/cellset.h
@@ -34,7 +34,7 @@ protected:
 	void init_p3r(){
 		init_p3();
 		fields.insert(std::pair<std::string, size_t>("radius", 3));
-		ip[0] = 3;
+		ip[3] = 3;
 	}
 public:
 	/// Constructor - create an empty cell set
diff --git a/stim/visualization/glObj.h b/stim/visualization/glObj.h
index 91546a5..e0be584 100644
--- a/stim/visualization/glObj.h
+++ b/stim/visualization/glObj.h
@@ -43,12 +43,17 @@ private:
 	}
 
 	void
-	Create(GLenum mode)
+	Create(GLenum mode, bool blend = false)
 	{
 //		GLuint selectBuf[2048];
 //		GLint hits;
 //		glSelectBuffer(2048, selectBuf);
 		
+		if(blend)
+		{
+			glEnable(GL_BLEND);
+			glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+		}
 		int len = (int) stim::obj<T>::numL();
 		std::vector< stim::vec<float> > line;
 		glNewList(dList, GL_COMPILE);
@@ -72,6 +77,8 @@ private:
 			}
 			glEnd();
 		}
+		if(blend)
+			glDisable(GL_BLEND);
 		glEndList();
 		CHECK_OPENGL_ERROR
 	}
@@ -83,11 +90,11 @@ public:
 	}
 
 	void
-	createFromSelf(GLenum mode = GL_RENDER)
+	createFromSelf(GLenum mode = GL_RENDER, bool blend = false)
 	{
 	//	glPopMatrix();
 		init();
-		Create(mode);
+		Create(mode, blend);
 	//	glPushMatrix();
 	}
 
--
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