diff --git a/pina/domain/ellipsoid.py b/pina/domain/ellipsoid.py
index 132bd55..5d46674 100644
--- a/pina/domain/ellipsoid.py
+++ b/pina/domain/ellipsoid.py
@@ -286,9 +286,6 @@ class EllipsoidDomain(DomainInterface):
         if self.fixed_ and (not self.range_):
             return _single_points_sample(n, variables).extract(variables)
 
-        if variables == "all":
-            variables = self.variables
-
         if mode in self.sample_modes:
             return _Nd_sampler(n, mode, variables).extract(variables)
         else:
diff --git a/pina/domain/simplex.py b/pina/domain/simplex.py
index 00bd980..6915c12 100644
--- a/pina/domain/simplex.py
+++ b/pina/domain/simplex.py
@@ -234,12 +234,11 @@ class SimplexDomain(DomainInterface):
             in ``variables``.
         """
 
-        # if variables == "all": # TODO: check if this is necessary (from 0.1)
-        #     variables = self.variables
-        # elif isinstance(variables, (list, tuple)):
-        #     variables = sorted(variables)
+        if variables == "all":
+            variables = self.variables
+        elif isinstance(variables, (list, tuple)):
+            variables = sorted(variables)
 
-        # if mode in ["random"]:
         if mode in self.sample_modes:
             if self._sample_surface:
                 sample_pts = self._sample_boundary_randomly(n)