diff --git a/pymotion/render/viewer.py b/pymotion/render/viewer.py
index d8d3ac2..aca4596 100644
--- a/pymotion/render/viewer.py
+++ b/pymotion/render/viewer.py
@@ -95,6 +95,14 @@ def add_skeleton(
         """
 
         assert data.ndim in (2, 3), "'data' must have shape [frames, joints, 3] or [joints, 3]"
+        assert parents.ndim == 1, "'parents' must have shape [joints]"
+        assert data.shape[-1] == 3, "'data' must have shape [..., 3]"
+        assert data.shape[-2] == parents.shape[0], "'data' and 'parents' must have the same number of joints"
+
+        if data.dtype != np.float64:
+            data = data.astype(np.float64)
+        if parents.dtype != np.int64:
+            parents = parents.astype(np.int64)
 
         if data.ndim == 2 or data.shape[0] == 1:
             self.static_objs.extend(
@@ -142,6 +150,10 @@ def add_sphere(
 
         assert sphere_mode in ("scatter", "mesh"), "'sphere_mode' must be 'scatter' or 'mesh'"
         assert center.ndim in (1, 2), "'center' must have shape [frames, 3] or [3]"
+        assert center.shape[-1] == 3, "'center' must have shape [..., 3]"
+
+        if center.dtype != np.float64:
+            center = center.astype(np.float64)
 
         if center.ndim == 1 or center.shape[0] == 1:
             if sphere_mode == "scatter":
@@ -185,6 +197,13 @@ def add_line(
         assert start.ndim in (1, 2), "'start' must have shape [frames, 3] or [3]"
         assert end.ndim in (1, 2), "'end' must have shape [frames, 3] or [3]"
         assert start.ndim == end.ndim, "'start' and 'end' must have the same number of dimensions"
+        assert start.shape[-1] == 3 and end.shape[-1], "'start' and 'end' must have shape [..., 3]"
+        assert start.shape[0] == end.shape[0], "'start' and 'end' must have the same number of frames"
+
+        if start.dtype != np.float64:
+            start = start.astype(np.float64)
+        if end.dtype != np.float64:
+            end = end.astype(np.float64)
 
         if start.ndim == 1 or start.shape[0] == 1:
             self.static_objs.append(
diff --git a/pyproject.toml b/pyproject.toml
index 881e915..0682380 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -10,7 +10,7 @@ exclude = ["*test*"]
 
 [project]
 name = "upc-pymotion"
-version = "0.1.9"
+version = "0.1.10"
 description = "A Python library for working with motion data in NumPy or PyTorch."
 readme = "README.md"
 authors = [{ name = "Jose Luis Ponton", email = "jose.luis.ponton@upc.edu" }]