Archive for aprile, 2013

aprile 24, 2013

dual meshes in blender

000 - cover_fx

Thanks to introduction of b-mesh it’s possible in blender, starting from a triangulated, to obtain a polygonal mesh in blender. This kind of polygonal mesh is called dual mesh.

Create a generic mesh surface in blender and then triangulate that. You can use the shortcut ctrl+T. Generally I suggest to start from a regular quad-grid, in order to achieve a more regular dual mesh:

001 - starting mesh

002 - triangulate

Now, add and apply a subsurf modifier, leaving the default settings. Now your mesh contains vertices of both starting and dual mesh. We need to surgically remove the starting mesh:

003 - subsurf modifier

For do that, we must select a vertice of the dual mesh. You can recognize it because it’s conected only to three edges. Now prest ctrl+ for “select more”:

004 - select more

Use now “select similar” tool (shift+G), and choose the option “Amount of Adjacent Faces” for select all similar vertices.
Invert the selection with ctrl+I and “Dissolve” the selected vertices:

005 - select similar

Now select one of the vertices connected to only two edges and use again the tool “select similar”. This time use the option “Amount of Connecting Edges”, and then dissolve all the selected vertices:

006 - select similar

Sometimes it’s possible that some quad faces must to be clean in a second moment, in this case you can use the same procedure for select all similar vertices. Furthermore, if your mesh is open, probably you have to clean the borders. To doing that quickly, you can simply use “Select Non Manifold” for select and delete the border vertices.

Here you can see the resulting mesh:

007 - final result

If you are lazy like me, you can also use a script that I created in order to automatically calculate the dual mesh: For do that, simply copy and paste the code inside the blender’s text editor, select your mesh and run the script.