Hello, i’m trying to render a single shot of a space filled with people, I would like to have a motion blur effect to simulate the movement of those.
Is there any chance to have this effect just with native Rhino and Vray?
No, only Maxwell supported object motion blur some years before.
You can create this effect pretty easy in 3ds max. Otherwise I would recommend a rendermask including all the people and then use photoshops motion blur to create the effect.
My eyes 
yes, how did you do that?
V-Ray supports both camera and object motion blur. You just need velocity vectors. Here I made a small 2 frame animation, where I rendered the second one. V-Ray takes velocities from the differentiation between the frames, and that’s it
Totally noob with gh but I totally understand the process. Are the object or the camera moving here? Could you share the gh file by any chance?
Thanks !
Is there a way to add vectors to objects? Best rotation and translation.
This is Camera motion blur here. I just moved the camera a bit i frame 2. for objects, velocities are inferred from the differences of the positions of the objects between the frames.
V-Ray for Rhino sets 1 frame per second, so every new frame advances the time by 1 second. Thus having positions and time V-Ray infers the velocity using simple linear equation (the one from 4th grade in school)
basically that’s it.
Is it possible to move the objects rather than the camera to obtain the same effect?
yes, but it is a bit more complex. You must be using V-Ray for Grasshopper for the object animation, but render the whole thing 8n Rhino, since no motion blur in VfGH
Also you may set the whole thing 8n GH and export a vrscene file. Then edit the file to manually enable the moblur.
it is a matter of preference.