diff --git a/qpms/latticegens.c b/qpms/latticegens.c
index 17867eb..034f934 100644
--- a/qpms/latticegens.c
+++ b/qpms/latticegens.c
@@ -175,7 +175,7 @@ PGenSph PGenSph_zAxis_new_minMaxR(double period, double offset, double minR, boo
         s->ptindex = ptindex_inc(s->ptindex);
       break;
     case PGENSPH_ZAXIS_INC_TOWARDS_ORIGIN:
-      s->ptindex = - ceil(minR / fabs(period));
+      s->ptindex = - ceil(maxR / fabs(period));
       while ( (curR = fabs(s->offset + s->ptindex * period)) > maxR || (!inc_minR && curR >= maxR))
         s->ptindex = ptindex_dec(s->ptindex);
       break;
diff --git a/qpms/vectors.h b/qpms/vectors.h
index 2eeaf5c..5e4e315 100644
--- a/qpms/vectors.h
+++ b/qpms/vectors.h
@@ -57,7 +57,11 @@ static inline sph_t cart2sph(const cart3_t cart) {
 
 static inline cart3_t sph2cart(const sph_t sph) {
 	cart3_t cart;
-	double sin_th = sin(sph.theta);
+	double sin_th = 
+#ifdef QPMS_VECTORS_NICE_TRANSFORMATIONS
+	   (sph.theta == M_PI) ? 0 :
+#endif
+		sin(sph.theta);
 	cart.x = sph.r * sin_th * cos(sph.phi);
 	cart.y = sph.r * sin_th * sin(sph.phi);
 	cart.z = sph.r * cos(sph.theta);
diff --git a/tests/test_latticegens.c b/tests/test_latticegens.c
index e9750ec..a7d1d82 100644
--- a/tests/test_latticegens.c
+++ b/tests/test_latticegens.c
@@ -1,5 +1,5 @@
 //c99 -o test_latticegens -ggdb -Wall -I ../ test_latticegens.c ../qpms/latticegens.c -lm
-
+#define QPMS_VECTORS_NICE_TRANSFORMATIONS
 #include <qpms/lattices.h>
 #include <stdio.h>
 
@@ -34,5 +34,15 @@ int main(int argc, char **argv) {
   dump_PGenSph(&g);
   DO_AND_PRINT(test3b, g = PGenSph_zAxis_new_minMaxR(0.2, 0.05, 5.05, false, 7.05, false, PGENSPH_ZAXIS_INC_TOWARDS_ORIGIN))
   dump_PGenSph(&g);
+  DO_AND_PRINT(test4a, g = PGenSph_zAxis_new_minMaxR(0.2, 0.0, 0, false, 1, false, PGENSPH_ZAXIS_INC_FROM_ORIGIN))
+  dump_PGenSph(&g);
+  DO_AND_PRINT(test4b, g = PGenSph_zAxis_new_minMaxR(0.2, 0.0, 0, false, 1, false, PGENSPH_ZAXIS_INC_TOWARDS_ORIGIN))
+  dump_PGenSph(&g);
+  DO_AND_PRINT(test5a, g = PGenSph_zAxis_new_minMaxR(0.2, 0.0, 0, true, 1, true, PGENSPH_ZAXIS_INC_FROM_ORIGIN))
+  dump_PGenSph(&g);
+  DO_AND_PRINT(test5b, g = PGenSph_zAxis_new_minMaxR(0.2, 0.0, 0, true, 1, true, PGENSPH_ZAXIS_INC_TOWARDS_ORIGIN))
+  dump_PGenSph(&g);
+
+
 }