Hey, I just want to know if it’s possible to make the Motion Blur affect only one layer, so that way I can place in that layer the objects i want to be affected by the blur. I’ve tried to tweak the settings of the blur in the node editor but it seems that the slow objects in my scene (the ones i don’t want to be blurred) are allways affected by the blur.
yes, but you have to put those objects on their own layer(s). Then create a new renderlayer in the RenderLayer panel, and specifiy only those layers, and be sure to enable Vector pass. Then, in the node editor, choose that renderlayer as the input source and run that to the vector blur node.
You will then have to mix that output with another renderlayer that renders everything else.
For your particular note, based on your desire to only blur the objects that are moving really fast, I would also think that you could run the Vector output through a Map Value node and clamp the low values, thus only let the higher vectors pass through to the vector blur. Off the top of my head I forget how, but it involves two map value nodes; one makes it negative and uses the min button to cut off small negative numbers, and the second multiplies again by a negative which flips them all around; except of course for the vectors made zero by the first map value.