Pack 009 Extrusion continued and Subdivision Surface Heikki Hietala IT Dept. Malmi Campus HAAGA-HELIA University of Applied Sciences

Extrusion produces crude results While extrusion is very well suited to millions of tasks, it is usually not enough alone What is needed is a Modifier called Subdivision Surface This, like all modifiers, lives in the Modifiers tab of the Properties window

Subdivision Surface (Subsurf) Subdivision Surface is a method of subdividing the faces of a mesh to give a smooth appearance, to enable modeling of complex smooth surfaces with simple, low-vertex meshes. This allows high resolution mesh modeling without the need to save and maintain huge amounts of data and gives a smooth organic look to the object. With any regular mesh as a starting point, Blender can calculate a smooth subdivision on the fly, while modeling or while rendering, using a simple dummy subdivision surface (Subsurf in short), or the smarter Catmull-Clark one. – Blender Wiki

A cube and three levels of Subsurf See the modifier panel The cube approaches a ball with just 2 subsurf levels The number of vertices grows with every level of Subsurf If you will not return to the subsurf, click Apply, but you don’t have to In fact, do not Apply without good reason.

An example: modeling the Babushka This is the famous recursive doll, Matrouschka from Russia There’s usually eight to ten of these dolls, each same shape, nested Let’s make this starting from a 12 vertex ring The top image shows the form of the joint

Phase 1 Start by adding a circle to the scene Reduce vertex count to 12 Switch to side view (1) Tab into Edit Mode and extrude up one (E – Z – 1 - Enter)

Phase 2 Drag the scene down (Shift+MMB) Scale out to something like this, or a bit wider Extrude again by 1 Scale out a bit Repeat once more for the bottom image shape

Note on edge loops If you need to return to a loop, you can Alt+RClick on it (see top ring selected) This way you can adjust the width of each ring on its own This is very important later on

Phase 3 Let’s make the inner wall With the top edge loop selected, hit E, and immediately S. This will let you scale in the new set of vertices as shown Now we will extrude down and scale when necessary.

Phase 4 Switch to Side view and turn on Wireframe viewing mode Extrude down, scale, and try to follow the outside lines Always use Z to keep the extrude straight.

Phase 5 At the bottom, add a couple of extrudes with just a little down movement and scale them in (top image) When you have the smallest ring selected, press Alt M (Merge) and select Center This will close the bottom Return to Solid shading

Phase 6 Extrude the outer bottom ring a little, and then Scale it out This will make you the foot part of the doll If you orbit around, you’ll see it is indeed a cup with outer and inner walls

Phase 7 Let’s close the outer bottom too Alt+RClick the bottom ring E to Extrude but hit Enter without moving anything Then Alt+M and Merge at Center See your Babouschka. Not exactly great just yet.

Now we bring in Subsurf Go into Object mode and find the Subdivision Surface modifier You will go from this to this Much better! Note the cage: you can edit individual vertices of the Subsurf cage, or faces, or edges.

Subsurfing When you try the View spinner, don’t go past 3 or 4, as it merely adds complexity but doesn’t enhance quality When you go to Object mode, this is what you see A lot better, but now we refine

Problems with Babouschka The foot is too small The top line of the bottom part curves in too much The top should be more or less vertical and it has a ridge, as you can see in the first slide. We can adjust all even if Subsurf is in use, because you can take it off with the eye

Fix the foot first This merely means grabbing the bottom edge loop and scaling it up Subsurf will even out large changes, so you may want to try a couple of scalings

Then adjust the top rings Aim for this. As you can see, I’ve scaled out the top ring and then extruded the inside top ring You may want to lift the outer top ring (selected) You can also add a Loop cut (bottom) and make the edge of the top sharper

The final bottom part This is pretty close to what you want. If you are a nitpicker, you should have two loops that you extrude for the ridge, I only had one. To get a full smooth surface, click Smooth when in Object mode I will leave it to you to design the top part Hint: duplicate the top edge loop to get a correct size starting point for the top part

Proper use of Subsurfing This is a wing-like structure made by extruding a plane that has been subdivided once. There’s 42 vertices 80 edges 40 faces File size is 380 kB

To make it look better, use subsurf The subsurf (2 levels) makes it look like a flintstone, not a wing But with a little loop rings added, it becomes much better on next slide

Just two loop rings … make all the difference Add one here and one here Still only 64 vertices

Ooops! I applied the subsurf! A whopping 994 vertices now. There is no easy way any more to edit just a part of the wing, which you can do very handily when the Subsurf is not applied Remember, the rendering subsurf does not affect the editing subsurf settings

The moral of the subsurf Use the Apply button on the subsurf modifier only if absolutely sure you will not return to the mesh anymore Use the View and Render spinners to see how your mesh will look when subsurfed You can leave the Render on 3 and it will still render in reasonable time.