Motion Blur - Accessing Layer's Transforms

if you're indeed making an artisan plugin, then we're entring the twilight zone...

first, let's tall 2 things apart:

1. the layer texture, where plug-ins render their output pre-layer-transformation, and the output is a 2d, untransformed image that's in the same coordinate space of the original layer image.

2. the layer transfomation, where the ready-to-use texture is then 2d or 3d transformed by the artisan and composited into the comp buffer.

now. "classical" motion blur, is where the transformation (clause 2 in the paragraph above) is repeaded multiple time in intervals between the transformation values of 2 points in time (usually the current time, and some point between the current time and the next frame's time).

some effects, such as prticale systems or element 3d, are not transfomed by the artisan, but instead mimik the comp's perspective and output an image that looks transformed even though the texture gets compsited at the layer's "rest" position in 2d.

now we're getting somewhere.

if you want to replace the comp's "built in" motion blur where layers move in 2D or 3D, then your can either write an artisan that does the WHOLE process of transforming and compositing, OR:

1. mimik the whole movement of the layer and have a simple layer plugin render the transformation along with the motion blur onto the layer texture, and the user would do that on an untransformed layer as he would with 3D effects.

2. ahve the layer transform normally, but you just add motion blur to the texture. that is tricky but possible. you'll need to deal with projections to tell what the next transformation of the layer would look like efrom the camera's point of view, and where that lands on the original layer at it's current position, and then blur the layer's image from it's rest position to the projected target position... if done correctly, you'll get a natural looking motion blur without forcing the user to work on a flat image and without writing an artisan. alas, in such a case i fail to see the point...

again, if you lay out the problem you're trying to solve, then parhaps i could help with a better strategy.