Wiggling ears tutorial.



Hello, since this is my first tutorial I'll start with a,very, short introduction of myself:
My name is Peder Kallin and I'm quite new to the XSI scene. I am currently studying Multimedia Design and digital animation in UK, where we use XSI as our 3D tool. I still have lots to learn so if there is some error in my tutorials please mail me at: capoeira_boras@hotmail.com

This tutorial can be posted anywhere, but can not be changed in ANY way. If anyone wants to change something, mail me. Due to some people still having 56k modems all images will be thumbnailed and can be clicked on to get a bigger image.

Lets start:
The goal with this tutorial is to create so called secondary motion. Lets say we have a rabbit jumping and we wants it ears to wiggle and deform in relation to how it moves. Well this is one way of doing it without having to set a lot of keys

1. First of, you can download this rar file (which includes a simplified bunny ear mesh and also the finsihed tutorial file), if you cant be bothered to make your own ears. What the scene consists of is just one ear and a polygon that emitts hair, the hair has been scaled up to better match the length of the ear.
2. Now we modify the strands to better match the shape of the ear. When you are done your scene should look something like this.
3. Okej, so we have our ear and we have the hair, now what? Well we need a way to envelope the ear to the hair. for this we are gonna use nulls, constrain the nulls to the hair and then use these to envelope. First step is to create the nulls, for my ear I am going to use 9 nulls and then place them out roughly like this (it really doesnt matter since we are going to position constrain them to the hair points/clusters).
4. So lets now constrain the nulls to the hair, to get a satisfactory result we are going to have to constrain each null to the matching four hair points. How do we do this? Well, we create clusters matching roughly with where we put our nulls. To create the clusters select four matching points and press the cluster button, do this 9 times so that each null have a set of points to be constrained to.
5. The constrain part next. The easiest way to do this, I think, is to open two explorer windows and have the nulls in one window and the hair clusters in one (the hair clusters are located under: grid->hair->hair-> clusters. The constrain type we use is "object to cluster". So object to cluster constrain all the nulls to the different clusters.
6. Time to envelope tihs, which can be pretty tricky if you have a "bad" mesh or havemt quite placed your nulls right. Select your ear and envelope it to all the ear nulls. You are probably going to have to change the weight of the enveloping.
7. Finally done, almost. The last thing we need to do is to set some forces to the hair so it actually moves and give us that secondary motion. Select the hair and in the hair panel add some gravity and perhaps some wind. After this press the dynamics button and viola! Now all you need to do is the tweak the hair settings to match your requirements.

Notes: If you are making for example ears dont forget to constrain/parent the polygon from which the hair emitts to the headbone.

Hope this tutorial will help someone.

Peder Kallin