Notes for Soft Body with Springs for Body Bounce

[Professor Watkins]

Notes for creating the soft body jiggle with extended Springs:

1 - Create the shape you will use to deform the mesh (this will become an Influence Object later). We'll call this the Influence.
2 - Create some polygonal shapes that you can use to hang springs off of. We'll call these Anchors.


Building Bounce for the Influence
We'll start out by making the influence object itself have some bounce and give.

3 - To give the object bounce we need to make it a soft body first. So start out by selecting the Influence object and selecting Dynamics.Soft/Rigid Bodies>Create Soft Body (Options). Make sure to use the settings shown below.


4 - Next we'll give this soft body some springs so taht it will bounce back. With the Influence object still selected, choose Dynaimcs.Soft/Rigid Bodies>Create Springs (Options).

5 - Name this set of springs InfluenceInnerSprings. Here we want to have springs that lay along the wireframe of the mesh so that it only stretches along the polygon edges. So be sure to change the Creation Method to Wireframe. The rest of the settings should be able to remain at default.


Attaching the Influence object to our Anchors
Next we'll make sure that this influence object has some springs to hang from. To do this we will attach some springs from the tips of the Influence object to the anchor objects. Or more specifically, we will attach the soft body particle that is at the ends of the Influence object to the inside vertices of the Anchor objects.

6 - Set up your component mask to only select Poly Vertices and Particles.

[Professor Watkins]

7 - Select the particle that is on the end of the Influence object and Shift-select the bottom two vertices of you Anchor. (You may want to hide the InfluenceInnerSprings object inth your Outliner first).


8 - Choose Dynamics.Soft/Rigid Bodies>Create Springs (Options). Be sure to change the Spring Name to "OutsideSprings" and change the Creation Method back to Min/Max since we want this spring to just keep track of a minimum and maximum amount of stretch. The settings should match this screenshot.


9 - The result will be a visual spring that connects the Influence object to the anchors.


10 - Repeat on the other side by selecting the outside particle of the Influence and the two inside vertices of the Anchor. Only this time, in the Outline, Cntrl-click the OutsideSprings1 object (since we are going to be adding to the already extant spring).

11 - Select again Dynamics.Soft/Rigid Bodies>Create Spring (Options). This time, just make sure that you check Add to Existing Springs. This will keep all of our Anchor springs in one object.

12 - So your scene should look like this:


Add Fields
Adding a bit of gravity will allow us to get started on the laborious act of tweaking

13 - Select the Influence object (the whole object and not just the Particles - so you probably want to select it in the Outliner). Select Dynamics.Fields>Gravity. Although if you hit play right now, not a whole lot would happen.

Tweaking
This is the most boring part; but ya gotta do it. Tweaking the values will help get the amount of motion you want that dies off at the rate you need.

14 - Animate the Anchors. Before you can see what your tweaks do, it will be necessary to have the scene animated so the dynamics can be seen. If you're adding this to a character that is already animated that's even better. But at least let the character jump up and down or something so you can see when youv'e got your tweaks right.

15 - Tweaks take place in three places:

• The ParticleShape node. Double-click the particle object in the Outliner to access this. More specifically, see the [i]Goal Weigts and Objects[i] section. The Goal Smoothness and the (in this case) pCubeShape1 settings will be important.
• The Springs for the Influence Object. More specifically, the Stiffness and Damping of those springs. They are accessible by double-clicking the springs in the Outliner and going to the InfluenceInnerSprings1Shape node.
• The springs that attach the Influence object to the anchors. Here again, more specifically, the Stiffness and Damping. Again; accessible by double-clicking the OutsideSprings1 object in the Outliner and choosing the OutsideSprings1Shape node.

16 - Every scene will be a little different. The size of your scene will define the size of your objects (both influence and anchors_) so there are no set values that we can plug in. But typically these things help:

• For the Particle Goal Smoothness: start around 4
• For the InnfluenceInnerSprigns Stiffness: Try high - like 150 to start
• For the InnerInfluenceSprings1 Damping try 6
• Try similar values to get started with for the OutsideSprings1Shape as well.

If you'd like to discect a file, be sure that you grab the attached .mb file. You can take a look at how it was set up. Be sure to remember though that the tweaking values are set for that scene only; and that your scene may take a bit more adjusting.

[Professor Watkins]

Here's the tutorial file if you'd like to take a look.

[Will]

WOA THIS IS REALLY COOOOL!!

wait. I have no idea wats going on..