[Bf-committers] Use cases for warp modifier?

[Campbell Barton]

On Fri, Jun 24, 2011 at 7:52 PM, Bassam Kurdali
<bkurdali at freefactory.org> wrote:
> On Fri, 2011-06-24 at 21:15 +0200, Tobias Oelgarte wrote:
>> Recently i noticed the "warp modifier" inside the current builds. In my
>> understanding it works like an improved hook. But i had only very few
>> cases in which needed hooks anyway. So im a bit puzzled. What is so
>> special about this modifier? Any known usecases?
>>
>> At first i thought you had implemented the "warp tool" as an modifier
>> and that it would be awesome. But then i tried it and didn't know what
>> to say. Truthfully i was a bit disappointed. ;P But it gives me a
>> headache; why we would need this modifier?
> because it is great! TBH when I first saw it I thought I'd never need
> it.
>
> it's very much like an improved hook, in that it is based on the
> difference between a reference and target empty. This way you can move
> the hook 'target' around without deforming the mesh (say with an
> armature, avoiding double deform), and then still use it to add a bit on
> top.
>
> use case: adding little tweak controls that let you modify the surface
> on a rigged character with extra bulges and moves, more specific things
> possible (e.g. muscles bulges, or in my case the lip-roll in and out
> motions on the character - invaluable given my choice of face rig.)
>
> use case: a hook that, unlike hook, you can 'move it' around the
> surface, so similar to lattice, you can move the deformation along the
> surface, for instance, to make a depression that moves around with a
> thing that causes it.
>
> It's a great modifier, but if you don't need it, don't use it. I think
> it was used in Sintel, so poking around those files might also give you
> clues.
>>
>> Greatings from
>> Tobias Oelgarte

Warp modifier was used in the Sentel room scene to animate her blanket
(not exciting but was useful in this case apparently).

Most of blenders deform tools use a fixed set of vertices, since the
warp modifier isn't it gives it a few novel advantages,

One example is an animal running about under a rug, you want the bulge
to move about and be animated freely without worrying about which part
of the rug.
Shrink wrap could be used too but I noticed ray casts can jitter when
the object moves about, Displace modifier with an object + texture
could be used too, but with displacement you have less control, its
only displacement in 1 direction.
With warp, if you want to displace more you just drag the object more.
To carry the creature-under-rug scenario further - with the warp
modifier you can do squash/stretch/twisting or a temp offset of the
deformation if the creature runs and stops suddenly.

Not sure if that example is the best, but certainly if you have many
modifiers applied and you end up with a confusing intersection, this
could be used as a bandade without the going through the trouble of
painting a new vertex group and assigning an extra armature.