how would you add vector blur and defocus together ?
I tried to put defocus before the vectorblur, but the z-depth is then not accurate …
First you need to understand that alpha channel effects (vector blur in this case) and depth channel effects (defocus) are not really compatible with each other. Vector blur will disrespect z-space tiem and tiem again. Why? Because it isn’t really geometry that the camera is looking at. Vector blur produces a 2D mask that basically smears the pixels around the screen. Vector blur will even disrespect the z-space within a single model. It is really only suitable for use when the models being blurred are only moving left to right and top to bottom on your screen and when the parts of those models do not move in front of them selves, otherwise you get some very undesirable effects. In some cases you can rotoscope the undesirable effects out. In other cases you scene basically gets trashed.
Knowing this you could try to to use stand ins such as planar objects objects which are at the proper distances from the camera as your blurred objects AND which cover the apropriate areas that are being vector blurred) to generate a depth map which you would then plug into the z-input of the defocus node while plugging a prerendered, vector blurred image sequence into the image input socket of the defocus node. That may or may not work. How ever you choose to go about it you are definitely in for a long and sweaty ride. Even if you don’t get it to work you will definitely learn a lot during the journey.
I too explored using both defocus and vector blur together. Take a look at the attached screenshot of my node layout.
In this example, the defocus DOES soften the vector blur to a degree, but the vector blur is still there. This was my first attempt with it, I believe additional experimentation may yield better results.
I have mine set up like Qigong’s and am not noticing a problem in regards to the combination of vector blur and motion blur. Maybe the problem has been fixed since 2005?
Vector blur itself is an odd beast, but when it works, it doesn’t keep defocus from working. As long as you defocus after blurring.