Ever since I saw Disney’s Meander tool I’ve been wanting it. I’m crazy about NPR and this is the absolute holy grail. If you feel like I do please read on.
This may be a shot in the dark, but if anyone else is interested in trying to find a way to do this in Blender, let’s start a discussion!
I’ve been doing research and I believe it is possible with Grease Pencil. But, there seems to be few major hurdles:
How to make a [point] displace in the x and y axes based on an vector motion sequence (image sequence).
How to “motion paste” [multiple points, ie. Grease Pencil strokes] to follow that image sequence, based on where they are placed on the image.
Motion Tweening is a whole different beast. The first two should be hard enough.
So… any ideas, comments, and suggestions are welcome. Anyone with a deeper understanding of what info the Vector (Speed) pass contains and how to utilize it in ways other than Blurring will be greatly appreciated. (I assume it outputs delta X and delta Y for next and previous frames = 4 values)
I was/am deeply fascinated by this approach and wondered also if an Open Source strategy could be developed. I don’t have any great wisdom to contribute, but will watch and see.
Unless I missed something, the Grease Pencil can’t automatically create strokes based on the geometry in the scene (the screenshot gives the impression of a cell-shading algorithm reading the scene to create the final frame.
@Isscpp quite a bit of this Grease Pencil can do but it’s not quite there. Grease pencil can parent to bones but I haven’t found a way for anything to follow motion vectors from an image.
@Ace Dragon the program Disney is using is much more simple, I believe, the strokes are just following the motion vectors underneath and blending between key frames. The shading is also drawn or uses another method altogether.
Actually it’s Folkert de Vries who made the Freestyle to GP script , I just made the reversed script to be able to render GP as Freestyle :
(Also I’m currently looking at ways to improve that freestyle baking to get colors and shadows also baked.)
But to answer the main topic, for now Grease Pencil as most of the tools to do as Disney, on some build it even have interpolation.
Vector motion is used because they don’t have the 3D drawing feature so they have to export enough data to be able to reconstruct motion. That’s not the case in Blender where we can draw in 3D and parent to object/armature.
The feature that is missing currently is GP deformation according to weight. And also, on the case of the Freestyle baking, a way to say “that stroke at frame 0 is the same as this one at frame 10” to be able to do interpolation or offset (and in 3D space it would be a dream).
so tl;dr : instead of copying exactly the tech, we can do the same by adaptating to Blender 3D space !
@zeauro Yes, the work Yadoob is doing is amazing and very useful. Thanks for the info!
@Yadoob they do have the tech to parent strokes to objects/armatures(bones) the reason they used 2d motion vectors is that it contradicts the 3d look - it makes you wonder if it’s 3d or 2d. With parenting directly on the 3d mesh it would look like a texture painted on a surface.
In order to solve this you can cover the mesh in bones that always ‘look at’ the camera and parent strokes to those bit it still wouldn’t, as you point out, have a weighted feel.
Since you have some experience with Grease Pencil development, is there anyway to get a look at the most recent code or get in contact with those in development? Thanks, Yadoob!
of course i don’t expect it to be there. But afair GP strokes can be drawn on mesh surfaces. That resembles that smile painted on the hand. And now we can also animate the strokes
I still think it would be cool to find solutions to opening up the use of the speed vector pass. It doesn’t just have to be about drawings. I can see it being very useful for denoising or anti aliasing or easily adding “decals” onto an object that maybe you forgot to add or didn’t want to add to an object in the scene for some reason. This might be possible already but I’ve never seen anyone do it.
@xalener Yes, the speed vector pass is extremely useful but nothing takes advantage of it. Just getting a modifier or addon that uses the speed pass for something other than blurring would be VERY powerful!!!
