22 lines
1.5 KiB
Markdown
22 lines
1.5 KiB
Markdown
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# Ozz-animation sample: Attachment to animated skeleton joints
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## Description
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Demonstrates how to attach an object to an animated skeleton's joint. This feature allows for example to render a sword in the hand of a character. This could also be used to attach an animated skeleton to a joint of an other animated object.
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## Concept
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The idea is to get the joint matrix from the model-space matrices array (for the selected "hand" joint), and use this matrix to build transformation matrix of the attached object (the "sword").
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Model-space matrices are outputted by LocalToModelJob. An offset (from the joint) can be applied to the joint transformation by concatenating an offset matrix to joint matrix.
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## Sample usage
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Some parameters can be tuned from sample UI to move the attached object from a join to an other, or change the offset from that joint:
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- Select the joint where the object must be attached: "Select joint" slider.
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- Offset of the attached object from the joint: "Attachment offset" x/y/z sliders.
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## Implementation
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1. Load animation and skeleton, sample animation to get local-space transformations, optionally blend with other animations, and finally convert local-space transformations to model-space matrices. See Playback sample for more details about these steps.
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2. Concatenate object offset transformation (offset relative to the joint) with joint model-space matrix to compute final model-space transformation of the "attached object".
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3. Use resulting transformation matrix to render "attached object" or update the scene graph.
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