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Con­ti­nuing from our recent report about model­ling, this week our animator and level designer Michael explains how he goes about ani­ma­ting our main cha­rac­ter.

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Posted in Animation | Mar 26, 2013 | by Michael Benda

Our Artist Phil­ipp Schürz alre­ady wrote about the art of model­ling. It is a huge task to com­bine com­pel­ling art and infle­xi­ble mecha­nics into a sin­gle piece of work. On the one hand the model has to be visually appealing and fit­ting to the over­all art con­cept, on the other hand the artist has to ensure tech­ni­cal accu­racy and plan ahead for the animator’s demands: e.g. the prot­ago­nist must be model­led in a neu­tral pose, allo­wing the ani­ma­tor to trans­form the model into any other pose requi­red after­wards. Also addi­tio­nal ver­ti­ces (edge loops) along joints have to be inclu­ded, to allow a smooth ben­ding of the model and reduce the dis­tor­ti­ons that may occur otherwise.

As soon as the model­ling is done and the team appro­ves the result, my job begins. It con­sists of two parts: rig­ging and ani­ma­tion.

3D model­ling soft­ware usually offers a vast variety of tools to help you with the rig­ging pro­cess. Still it can be a huge pain when not done cor­rectly, and is often the main rea­son for pro­blems and slee­p­less nights, if those errors don’t reveal them­sel­ves until half of the ani­ma­tion pro­cess is alre­ady finis­hed.
Sim­ply said, one just has to prop up the model with a ske­le­ton and asso­ciate each ver­tex of the model to a joint. Thus, when the joint gets modi­fied the trans­for­ma­tion gets pro­pa­ga­ted to the respec­tive ver­ti­ces. As long as one keeps in mind to create a sim­ple hier­ar­chy and clean initial joint trans­for­ma­ti­ons, as well as the imp­li­ca­ti­ons of inverse kine­ma­tics and the extreme poses one wis­hes to achieve, ever­y­thing should work out well.

With this ske­le­ton made of bones and joints one could alre­ady start the ani­ma­tion pro­cess. And if it is sup­po­sed to be a sim­ple model with a short ani­ma­tion, that is what I do. But as soon as you aspire more than that, I warmly recom­mend to make your life much easier by adding addi­tio­nal fea­tures to your model. Instead of rota­ting each joint sepa­ra­tely you can create spe­cial objects to serve as con­trol hand­les, or con­trols. You con­nect the trans­for­ma­ti­ons of the con­trols to spe­ci­fic joints, IK hand­les or other values by using cons­traints. Now those con­trols allow me to have sim­ple access to com­plex actions of our prot­ago­nist. Ben­ding down requi­res a trans­for­ma­tion of only a sin­gle con­trol object; for loo­king in one direc­tion while hop­ping up and down and doing turns and twists, I only have to put one con­trol handle in the right position.

Finally there is the ani­ma­tion pro­cess. The two methods used most fre­quently are the strai­ght ahead approach and pose to pose ani­ma­tion. By using the first con­cept you create your ani­ma­tion chro­no­lo­gi­cally star­ting at the first frame. This allows the ani­ma­tion of more flu­ent and fle­xi­ble move­ment, but is also limited due to the lack of con­trol over accu­rate timing. Since timing is a big issue in the game flow, I pre­fer the pose to pose approach where one crea­tes fixed key poses for the ani­ma­tion and after­wards fills the mis­sing frames in bet­ween. E.g. I use fol­lo­wing four poses to ani­mate the run cycle of the prot­ago­nist – con­tact, pass, up and air.

Key Pose Animation

After the key poses are set, the 3D model­ling pro­gram can usually inter­po­late the frames in bet­ween. But since most of the time this leads to unna­tu­ral motion – like feet that move magi­cally through solid ground or knees twit­ching back and forth (knee pop­ping) – most of the time nee­ded for the ani­ma­tion pro­cess is spent twea­king the result until the model fits the expec­ta­ti­ons.
But once all the fiddling is done the click on the export but­ton can be pretty rewarding.

PS: Don’t for­get .. DON’T FORGET to save your pro­gress BEFORE cli­cking on this par­ti­cu­lar button…

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