Blender 3D: Noob to Pro/Simple Cloth Animation

In this tutorial, we will be making a simple skirt.

Making the Skirt Mesh

1. Open Blender and delete the default cube, if you aren't looking down on the scene, press NUM7.
2. SPACE → Add → Mesh → Circle (Blender 2.5 users press "Shift-A" to open the "Add" menu)
3. You should get a prompt for the number of vertices. Use about 12 and hit OK.
4. Once the circle is added, switch to Edit Mode with TAB. All the circle’s vertices should be initially selected; if not, use AKEY to select them all.
5. Press EKEY and select “Only Edges” to extrude a second copy of the vertices; press SKEY SHIFT+ZKEY to scale the extruded vertices in the X and Y directions. These will make up the hem of the skirt; scale it out to as large as you like. Note that this is positioning the skirt out flat horizontally, instead of hanging down as you would expect; Blender’s cloth animation system will take care of that, and this positioning gives maximum opportunity for the skirt fall in dramatic folds.
6. Now we will need to subdivide the mesh. The physics can only act on actual vertices, so the more of these we have, the more realistic the cloth effect will be. Select all vertices in the skirt, press WKEY and select the “Subdivide Multi” option; choose, say, 4 for the number of cuts, and hit OK.
7. While you’re at it, go to the “Link and Materials” buttons, and click “Set Smooth”.

Creating the Vertex Group

1. Now we have to specify that the waist of the skirt will stay fixed in place as it falls: deselect all vertices, and select the innermost ring of vertices. The easiest way to do this is select two consecutive vertices in that ring, then press CTRL+EKEY and use the “Edge Loop Select” option.(ShortCut: Alt + Click edge to select closet loop) With those vertices selected, go to the Editing buttons, in the “Link and Materials” miniwindow, under “Vertex Groups”, click “New”, perhaps give it a more meaningful name (like “Waist”), and click “Assign” to put the selected vertices into the new group.

Animating the Skirt

1. Tab out of Edit Mode into Object Mode. The skirt should still be selected.
2. Switch the Buttons Window to Object Context (F7), and select the Physics Buttons (second in the row of three icons that appears to the right of the context buttons).
3. Among the miniwindows should be one titled “Cloth”. Click the “Cloth” button in it; a whole lot of other settings should appear, most of which can be left at their default values. However, click the button titled “Pinning of cloth”; this will make a popup menu of the available vertex groups in the object. Since you only created one vertex group (the “Waist” one), this should already be selected by default.
4. Now the magic happens ... rotate the view to an oblique one to give yourself a good view of the process, and hit ALT+AKEY. You should now see the skirt fall from its horizontal position to a more natural vertical one, developing some folds in the process.
5. After the animation has run through at least one complete cycle, hit ESC to stop it.

Keeping the Folds

1. Now use the left- and right- arrow keys to step through the animation one frame at a time, until you find a position for the skirt that you like.
2. When the 3D view is showing a nice shape for the skirt, go to the “Object” menu, and look for the “Scripts” submenu. In here there should be a script called “Apply Deformation”. Select it.
3. It looks like nothing has happened, but in fact you now have a second copy of the skirt mesh, “baked” into the position corresponding to the current frame of the animation. Try using the arrow keys to move through the animation, and you will see the baked copy remain in the chosen position.
4. At this point, you can delete the original animated skirt mesh (or move it to another layer for future reuse), leaving the nicely-folded copy.

Extra Practice

1. You will notice at some points during the animation, the folds of cloth pass right through each other, which is of course impossible with real cloth. To prevent this, you could go to the “Collision” tab in the “Cloth” miniwindow, and click the “Enable selfcollisions” button. Rerun the animation (ALT+AKEY) to see the difference; what other effects does it have?
2. Maybe the folds don’t look realistic enough. Go back to the original mesh, bring up “Subdivide Multi” again and subdivide it by a couple more levels. Rerun the animation (ALT+AKEY). It should take a bit longer for the first cycle, but do the results look better?
3. This YouTube tutorial might also help: http://au.youtube.com/watch?v=mgYhZ3hWwTQ happy animating!