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Building animations

AUTHOR: Mike McGoveran
DATE: 6/29/23


The problem:
While building a new Spider Boss  I found that the available animations that came with the asset were lack luster and didn't really open up the capacity to run behaviors akin to what one would like a spider to do.  In my case I had decided to take the opportunity to go a little outside the box and fire a laser from it's rear-end.  In order to make it sweep the laser I would need an animation to mimic this.   My first thought was to just have it rotate it's legs while stationary, however I felt that this wouldn't look right considering there is limited animation input to draw from for a rotating animation.  Since there is no animation available that fits this behavior I decided to instead go for a rotating the abdomen while using it's legs to brace it.  But how could I make such an animation?

The Solution:

The first thing I looked at was telling the animation BP to do something moving each bone at a time.   This solution was immediately apparent to be painful to build and unrealistic to pursue,  but it did result in me making a passive throbbing of the abdomen that increased the creepiness of the spider.  Instead I landed on the ability to deconstruct and re-bake existing animations.  The first step I had was to drop an animation sequencer into my level as a testing tool.  Then I imported the Skeletal mesh into the sequencer.   Upon doing so I found the skeleton lacked a control rig.   So I build a whole new control rig for the asset that would allow me to manipulate each bone on the spider.  The next step was to import in the idle animation on the spider and bake it onto the control rig I created. 

After that was done I had to remove the keyframes I didn't need on the parts I planned to manipulate and add instructions for each bone at the extent of each movement I wanted to make.   The animation would then lerp between each keyframe I put in instruction. 

 From there I could then re-bake the whole sequence back into a whole new animation. 

 Considering I am a developer playing the designer role with zero experience with any of these systems.  I found the system fairly easy to operate after watching a few tutorials.

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