update docs

Author: akaszynski

docs/source/api_reference/pyvista.rst

@@ -3,25 +3,25 @@ PyVista
 
 https://docs.pyvista.org
 
-PyVista is a great library that exposes a high level API for vtk, it has way more features
-than ipygany. For this reason, ipygany supports PyVista objects:
+PyVista is a great library that exposes a high level API for ``vtk``
+and it has way more features than ``ipygany``. For this reason,
+``ipygany`` supports PyVista objects:
 
 
 .. jupyter-execute::
 
     import pyvista as pv
     from pyvista import examples
 
-    pvmesh = examples.download_st_helens()
-    ugrid = pvmesh.cast_to_unstructured_grid()
-
     from ipygany import PolyMesh, Scene, IsoColor, Warp
 
-    # Turn the PyVista mesh into a PolyMesh
-    mesh = PolyMesh.from_vtk(ugrid)
+    # Download a pyvista example and convert it to a PolyMesh
+    pvmesh = examples.download_st_helens()
+    mesh = PolyMesh.from_pyvista(pvmesh)
+
+    # Plot it
     warped_mesh = Warp(mesh, input=(0, 0, ('Elevation', 'X1')), warp_factor=1.)
     colored_mesh = IsoColor(warped_mesh, input='Elevation', min=682, max=2543)
-
     Scene([colored_mesh])
 
 
@@ -30,13 +30,12 @@ than ipygany. For this reason, ipygany supports PyVista objects:
     import pyvista as pv
     from pyvista import examples
 
-    nefertiti = examples.download_nefertiti()
-    ugrid = nefertiti.cast_to_unstructured_grid()
-
     from ipygany import PolyMesh, Scene, IsoColor, Warp
 
-    # Turn the PyVista mesh into a PolyMesh
-    mesh = PolyMesh.from_vtk(ugrid)
-    mesh.default_color = 'gray'
+    # Download the pyvista nefertiti example and convert it to a PolyMesh
+    nefertiti = examples.download_nefertiti()
+    mesh = PolyMesh.from_pyvista(nefertiti)
 
+    # Plot it
+    mesh.default_color = 'gray'
     Scene([mesh])

ipygany/ipygany.py

@@ -298,9 +298,9 @@ def from_pyvista(obj, **kwargs):
 
         # convert to an all-triangular surface
         if surf.is_all_triangles():
-            trimesh = surf.triangulate()
-        else:
             trimesh = surf
+        else:
+            trimesh = surf.triangulate()
 
         # finally, pass the triangle vertices to PolyMesh
         triangle_indices = trimesh.faces.reshape(-1, 4)[:, 1:]