How to create custom animation from glb file with joints

[michaelaeriksen]

How do I animate a model? I have a glb file with joints, but I'm lost trying to animate the model.

When I print the model I get something like this

VsgVisitor::apply(vsg::MatrixTransform&)
VsgVisitor::apply(vsg::Group&)
VsgVisitor::apply(vsg::Group&)
VsgVisitor::apply(vsg::Object&) N3vsg20BindGraphicsPipelineE
VsgVisitor::apply(vsg::Object&) N3vsg17BindDescriptorSetE
VsgVisitor::apply(vsg::Object&) N3vsg14PipelineLayoutE
VsgVisitor::apply(vsg::Object&) N3vsg13DescriptorSetE
VsgVisitor::apply(vsg::Object&) N3vsg19DescriptorSetLayoutE
VsgVisitor::apply(vsg::Object&) N3vsg15DescriptorImageE
VsgVisitor::apply(vsg::Object&) N3vsg15DescriptorImageE
VsgVisitor::apply(vsg::Object&) N3vsg15DescriptorImageE
VsgVisitor::apply(vsg::Object&) N3vsg16DescriptorBufferE
VsgVisitor::apply(vsg::Object&) N3vsg16DescriptorBufferE
VsgVisitor::apply(vsg::Object&) N3vsg16DescriptorBufferE
VsgVisitor::apply(vsg::Object&) N3vsg22BindViewDescriptorSetsE
VsgVisitor::apply(vsg::Object&) N3vsg14PipelineLayoutE
VsgVisitor::apply(vsg::Object&) N3vsg15VertexIndexDrawE
VsgVisitor::apply(vsg::Group&)
VsgVisitor::apply(vsg::Object&) N3vsg20BindGraphicsPipelineE
VsgVisitor::apply(vsg::Object&) N3vsg17BindDescriptorSetE
VsgVisitor::apply(vsg::Object&) N3vsg14PipelineLayoutE
VsgVisitor::apply(vsg::Object&) N3vsg13DescriptorSetE
VsgVisitor::apply(vsg::Object&) N3vsg19DescriptorSetLayoutE
VsgVisitor::apply(vsg::Object&) N3vsg15DescriptorImageE
VsgVisitor::apply(vsg::Object&) N3vsg15DescriptorImageE
VsgVisitor::apply(vsg::Object&) N3vsg15DescriptorImageE
VsgVisitor::apply(vsg::Object&) N3vsg16DescriptorBufferE
VsgVisitor::apply(vsg::Object&) N3vsg16DescriptorBufferE
VsgVisitor::apply(vsg::Object&) N3vsg16DescriptorBufferE
VsgVisitor::apply(vsg::Object&) N3vsg22BindViewDescriptorSetsE
VsgVisitor::apply(vsg::Object&) N3vsg14PipelineLayoutE
VsgVisitor::apply(vsg::Object&) N3vsg15VertexIndexDrawE
VsgVisitor::apply(vsg::joint&)base
VsgVisitor::apply(vsg::joint&)a_1
VsgVisitor::apply(vsg::joint&)a_2
VsgVisitor::apply(vsg::joint&)a_3
VsgVisitor::apply(vsg::joint&)a_4
VsgVisitor::apply(vsg::joint&)b_1
VsgVisitor::apply(vsg::joint&)b_2
VsgVisitor::apply(vsg::joint&)b_3
VsgVisitor::apply(vsg::joint&)b_4
VsgVisitor::apply(vsg::joint&)c_1
VsgVisitor::apply(vsg::joint&)c_2
VsgVisitor::apply(vsg::joint&)c_3
VsgVisitor::apply(vsg::joint&)c_4
VsgVisitor::apply(vsg::joint&)d_1
VsgVisitor::apply(vsg::joint&)d_2
VsgVisitor::apply(vsg::joint&)d_3
VsgVisitor::apply(vsg::joint&)d_4
VsgVisitor::apply(vsg::joint&)e_1
VsgVisitor::apply(vsg::joint&)e_2
VsgVisitor::apply(vsg::joint&)e_3

I assume I need to use a JointSampler, but I can't find any examples in vsgExamples.

right now I have something like this, but I assume I need to add the joints and then somehow update the joint rotations

  auto jointSampler = vsg::JointSampler::create();

  auto animation = vsg::Animation::create();
  animation->samplers.emplace_back(jointSampler);

  auto animationGroup = vsg::AnimationGroup::create();
  animationGroup->animations.push_back(animation);

  auto scene = vsg::MatrixTransform::create();
  scene->addChild(model);
  scene->addChild(animationGroup);

How do I set the rotation of lets say joint:c_1 from code?

Any help would be appreciated.

[robertosfield]

With your VsgVisitor you should be able to use object.className() to return a human readable name.

With the GLB file I would have expected that the glTF loader would have inserted an vsg::AnimationGroup above the animated subgraph with vsg::Animation above it. These animations would do the animations for you. I don't see any AnimationGroup in the snippet you've provided which is curious.

The vsganimation example illustrates how to find the Animation's and then activate them by assigning them to the viewer's vsg::AnimationManager.

Could you try running vsganimation with your .glb file to see what happens?

[AnyOldName3]

Is there even an animation in the model? Some collections of assets will store them separately so you can reuse the same animations for several characters or sets of accessories without having to duplicate all the animations in all the assets.