animating footprints

Man, is the search on this forum lacking.

I’m sure this has come up as a topic before, but I find myself needing to put footprints into snow and I was wondering if anyone’s figured out simple ways of doing this in Blender.

I’ve come up with only two solutions:

  1. Use proportional editing with footprint-like meshes and move them downwards. (See attached pic.) Problem with this is that the snow mesh then has to be very, very polygon heavy. This is based on a suggestion by Modron that I found after a lot of searching.

  2. Use an animated texture to displace the surface. I could do this if I first modeled my character’s walk and then marked where its feet fall, but it seems overly tedious.

Is there anything better out there?

http://ministryofdoom.org/cloud/blender/20060119/shot1.png

You can use an image of all the footprints as a bump map, and progressively uncover it with a stenciled Blend texture. The mask needs to be in the texture slot above the feetprints.

Look in the wiki if you are unfamiliar with stencils:

http://mediawiki.blender.org/index.php/Manual/PartIV/Map_To#Stencil

Key the offset of the stencil and use Constant IPO’s to make the prints appear in a stepwise rather than gradual manner.

EDIT:

  1. Use an animated texture to displace the surface. I could do this if I first modeled my character’s walk and then marked where its feet fall, but it seems overly tedious.

Ah sorry, the first time round I somehow missed that you don’t want to use animated textures. I’ll think about it more, and hope someone else finds this method useful anyway!

Hiya,

Actually using a stencil map with a ramp to gradually uncover the prints is a neat idea… I’m going to give it a try. As far as animated textures go, I meant I’d thought to make the prints on a flat texture and have them fade in, then map that animated movie to a texture. Your way would be a lot quicker, although it still requires that the placement of every footstep is known beforehand.

However, that’s better than what I had. ^-^ Cheers!

Any other takers?

I’m interested in seeing what you can do with this.

For another strategy, I vaguely remember seeing a post about doing prints by applying a build effect on modeled rows of feet. I think it inverted the Z buffer to make them into dents? Can’t find it with the bleeping search function though; maybe you’ll have better luck.

Here’s a wierd thought, use RVKs

Define a shape key for each footprint then have each one in turn go from 0 to 1 effect in a few frames.

Now that would be a sweet trick, and a perfect use of shape keys

Like this:

footprints.blend

Ok here’s another bizarro idea that’s tedious but might work. Model and duplicate a bunch of “footprints” with the same material as the ground. Add a bumpmapped texture so they look indented. Step through your animation and place one print at each footfall. Keep track of the order they go down.

Now to every print, add a copy location constraint that copies the footprint location to an Empty object vertex-parented to the foot.

For each print, in the IPO editor key the influence of this constraint so it starts at 1, then at the frame when the foot touches the ground change it to zero. Of course you’ll have to keep track of which print is which so they appear in order.

The net effect will be to have the foot “carrying” a bunch of prints, then depositing them in place at the keyframe for each footstep.

Whoa, my idea’s overly complicated. If you’re going to premodel and place the footprints anyway, just put them all on a non-rendered layer and key a change to a visible layer at each step. Forget all that guff about copy location constraints, gah!

Yeah, I had that thought too… instead of RVKs, though, I’d go with shape keys and object drivers so that I can line up the amount of displacement with the character’s foot by moving the object with the foot’s IK handle.

Well, I found some nice displacement settings and managed to get them working on a not-too-poly-heavy surface, but the stencil texture is giving me grief. Has anyone gotten it to work on a bump map? What’s the secret? So far the only thing I’ve been able to stencil is the color map:

http://ministryofdoom.org/cloud/blender/20060120/snowtest2.jpg

I intentionally left it colored here. What I want is to have the pawprints in half of that image disappear. Anyone have any clues?

Well, I’ve been working on a script that if modified quite a bit might produce the right effect. It works by deforming the vertices of the mesh near an object (usually an empty) either away from the empty or towards the empty. It uses the custom properties (found on the Logic/Game panel) to store settings, etc. required by the script.

If this script is modified so that it:
a) makes a deformation stay, after the object has moved away
b) deforming the mesh by other mesh objects
it should be perfect for this task.

Originally, I started working on it so that I could have a cheap way to animate/simulate ocean waves. However, in its current state, the results produced are quite ugly.

Aligorith

Oh oh - Me again!

Hooks - I forgot hooks!

Use an empty for each footstep and make it a hook for each footstep, then just push the hook into the snow at each foot location!

Yeah, I had that thought too… instead of RVKs, though, I’d go with shape keys and object drivers so that I can line up the amount of displacement with the character’s foot by moving the object with the foot’s IK handle.[/quote]

Um… Shape keys ARE RVKs !!!?!??! :o

…but just to be a little obnoxious - Why try to set up drivers to the foot IK? Are you trying to create an animation or mimic real life?

Sorry for the small rant, but when I see what Aardman goes through to make a second of animation, being able to do what we can do with Blender is heaven without having to automate every little thing!

PS: I like your paw prints!

Kattkieru: Here is a crude blendfile of an animated stencil uncovering footprints. A colorbanded blend texture works best, mapped only to Stencil with NoRGB. Stencil’s offset is keyed using Constant curves. Remember to npack the file so you get the textures.

http://www.savefile.com/files.php?fid=1808018

EDIT: Uploaded link to file with bumpmap texture properly packed.

Oh hey, I did too! :stuck_out_tongue: I never used that feature; it begs some investigation.

The way you work with them is very different to me… shrugs I mean, I know they work using the same basic principals but in my head they’re very different. For one, Shapes are waaaay easier to set up, modify and remove.

Well, I’m trying to match. I want this looking as good as I can make it look without having it be a pain in the ass. That’s why I’m willing to explore a lot of different avenues.

Cheers. :slight_smile: But they won’t be the final ones. I’m animating a fox, and fox prints are smaller and more together, without the toes being so splayed:

http://ministryofdoom.org/cloud/blender/20060120/foxprints1.jpg

… although my fox’s proportions are cartoony, so his paws may well be larger than normal for his size.

CD38: You rock.

Well, your blend sorted me-- now stencils are working fine on bump maps, but they still fail on displacement maps. It’s looking more and more like I’m going to have to model in the detail and use shapes or hooks or something to make the changes.

… or an animated displacement map.

Thank you all so much for your help! I’ve got a fairly decent thing going now using two hooks per paw and some arcane trickery.

Here’s a movie: http://ministryofdoom.org/cloud/blender/20060120/print-test3.mp4 . What do you think? I know it’s a little fast and the specular on the snow is still too high (haven’t found a nice setting for that yet), but it’s about as close as I’m going to get without a fluid sim, I think.