Assigning bone transform in every draw a good idea?

Question

In my Draw method, I am doing the following:

thisMesh.CopyAbsoluteBoneTransformsTo(transforms);

Is this a good idea? Or should I do this once at the constructor level?

Answer 1

If the bones are static and so are the transforms, you only need to apply the transforms once. You can do that in the constructor.

However, if you're using the bones to position the model or animate the model, you'll need to update them more often. How often depends on how you're using them. For example, you may be reusing the same model and bones to draw multiple instances of a single model. In this case you'd have to update the transforms every frame. If you're just animating one model, you only need to update the transforms on a pose change. That could be at the same speed as your frame rate or it could be slower, it depends on your animation speed and run speed.