Wesley Smith

There was some talk a few weeks ago about vertex skinning. Here's a

patch that demos the technique. It's a little hairy, especially the

vertex shader, but it does work. This patch is not completely error

free yet. For some reason the vertex interpolation is squishing

segments together and I haven't figured out why, but I think the idea

I've divided the mesh into 5 sections, each controlled by the position

and rotation (modelview matrix without the scale) of a gridshape. I

generated a cylindrical mesh and assigned each vertex to a section

(bone in the vertex skinning terminology) and a weight. The weight

says how much a given vertex is affected by a particular bone.

Getting all this data into a vertex shader is a bit tricky. Here I

put the weights in the texture coordinate matrix and the bone

assignment in the tangents matrix. This choice was for convenience

The trickiest part of this whole business is getting the modelview

matrix for each segment ( aka the bone matrices) into the shader. To

conserve space, only the rotation and translation portions of the

matrix are sent which ends up being a 3x4 matrix. In the shader,

these are stored as an array of vec4s. For convenience, I actually

send the transpose of the 3x4 bone matrix so that a row of the matrix

is stored in a single vec4. Again, this isn't the only way to go. In

the shader, I build a modelview matrix from this data and use it to

Theoretically, all of this data could be generated in Maya. Maya has

really nice tools for building skins and bones for a mesh, but the

m********* f********* has really lame export facilities. I tried

about half a dozen plugins that supposedly export skin and bone data

but none of them worked. If someone knows how to do this, I would be

http://www.mat.ucsb.edu/~whsmith/PlaydoughMesh.zip

Hi everyone,
There was some talk a few weeks ago about vertex skinning.  Here's a
patch that demos the technique.  It's a little hairy, especially the
vertex shader, but it does work.  This patch is not completely error
free yet.  For some reason the vertex interpolation is squishing
segments together and I haven't figured out why, but I think the idea
still comes across.

Here's how it works:
I've divided the mesh into 5 sections, each controlled by the position
and rotation (modelview matrix without the scale) of a gridshape.  I
generated a cylindrical mesh and assigned each vertex to a section
(bone in the vertex skinning terminology) and a weight.  The weight
says how much a given vertex is affected by a particular bone.
Getting all this data into a vertex shader is a bit tricky.  Here I
put the weights in the texture coordinate matrix and the bone
assignment in the tangents matrix.  This choice was for convenience
but is not the only way to do it.

The trickiest part of this whole business is getting the modelview
matrix  for each segment ( aka the bone matrices) into the shader.  To
conserve space, only the rotation and translation portions of the
matrix are sent which ends up being a 3x4 matrix.  In the shader,
these are stored as an array of vec4s.  For convenience, I actually
send the transpose of the 3x4 bone matrix so that a row of the matrix
is stored in a single vec4.  Again, this isn't the only way to go.  In
the shader, I build a modelview matrix from this data and use it to
find a new position for the vertex.

Theoretically, all of this data could be generated in Maya.  Maya has
really nice tools for building skins and bones for a mesh, but the
m********* f********* has really lame export facilities.  I tried
about half a dozen plugins that supposedly export skin and bone data
but none of them worked.  If someone knows how to do this, I would be
most grateful to know how.

Here's the link.
http://www.mat.ucsb.edu/~whsmith/PlaydoughMesh.zip

playdough-mesh

hmm - Wes, when I hit initMesh, I get an instant crash

On Jan 2, 2007, at 1:24 AM, Wesley Smith wrote:

> There was some talk a few weeks ago about vertex skinning. Here's a

> patch that demos the technique. It's a little hairy, especially the

> vertex shader, but it does work. This patch is not completely error

> free yet. For some reason the vertex interpolation is squishing

> segments together and I haven't figured out why, but I think the idea

> I've divided the mesh into 5 sections, each controlled by the position

> and rotation (modelview matrix without the scale) of a gridshape. I

> generated a cylindrical mesh and assigned each vertex to a section

> (bone in the vertex skinning terminology) and a weight. The weight

> says how much a given vertex is affected by a particular bone.

> Getting all this data into a vertex shader is a bit tricky. Here I

> put the weights in the texture coordinate matrix and the bone

> assignment in the tangents matrix. This choice was for convenience

> The trickiest part of this whole business is getting the modelview

> matrix for each segment ( aka the bone matrices) into the shader. To

> conserve space, only the rotation and translation portions of the

> matrix are sent which ends up being a 3x4 matrix. In the shader,

> these are stored as an array of vec4s. For convenience, I actually

> send the transpose of the 3x4 bone matrix so that a row of the matrix

> is stored in a single vec4. Again, this isn't the only way to go. In

> the shader, I build a modelview matrix from this data and use it to

> Theoretically, all of this data could be generated in Maya. Maya has

> really nice tools for building skins and bones for a mesh, but the

> m********* f********* has really lame export facilities. I tried

> about half a dozen plugins that supposedly export skin and bone data

> but none of them worked. If someone knows how to do this, I would be

OSX 10.4.8 Intel macbook pro
max 4.6.2
jitter 1.6b2

> Hi everyone,
> There was some talk a few weeks ago about vertex skinning.  Here's a
> patch that demos the technique.  It's a little hairy, especially the
> vertex shader, but it does work.  This patch is not completely error
> free yet.  For some reason the vertex interpolation is squishing
> segments together and I haven't figured out why, but I think the idea
> still comes across.
>
> Here's how it works:
> I've divided the mesh into 5 sections, each controlled by the position
> and rotation (modelview matrix without the scale) of a gridshape.  I
> generated a cylindrical mesh and assigned each vertex to a section
> (bone in the vertex skinning terminology) and a weight.  The weight
> says how much a given vertex is affected by a particular bone.
> Getting all this data into a vertex shader is a bit tricky.  Here I
> put the weights in the texture coordinate matrix and the bone
> assignment in the tangents matrix.  This choice was for convenience
> but is not the only way to do it.
>
> The trickiest part of this whole business is getting the modelview
> matrix  for each segment ( aka the bone matrices) into the shader.  To
> conserve space, only the rotation and translation portions of the
> matrix are sent which ends up being a 3x4 matrix.  In the shader,
> these are stored as an array of vec4s.  For convenience, I actually
> send the transpose of the 3x4 bone matrix so that a row of the matrix
> is stored in a single vec4.  Again, this isn't the only way to go.  In
> the shader, I build a modelview matrix from this data and use it to
> find a new position for the vertex.
>
> Theoretically, all of this data could be generated in Maya.  Maya has
> really nice tools for building skins and bones for a mesh, but the
> m********* f********* has really lame export facilities.  I tried
> about half a dozen plugins that supposedly export skin and bone data
> but none of them worked.  If someone knows how to do this, I would be
> most grateful to know how.
>
> Here's the link.
> http://www.mat.ucsb.edu/~whsmith/PlaydoughMesh.zip
>
> best,
> wes

Don't hit init mesh then. It gets called on loadbang anyway. Just

turn on the metro. I was getting alot of crashes as well with this

patch but it worked on my macintel imac with jitter b3.

> hmm - Wes, when I hit initMesh, I get an instant crash

> On Jan 2, 2007, at 1:24 AM, Wesley Smith wrote:

Don't hit init mesh then.  It gets called on loadbang anyway.  Just
turn on the metro.  I was getting alot of crashes as well with this
patch but it worked on my macintel imac with jitter b3.

On 1/1/07, vade  wrote:
> hmm - Wes, when I hit initMesh, I get an instant crash
>
> OSX 10.4.8 Intel macbook pro
> max 4.6.2
> jitter 1.6b2
>
>
>
> On Jan 2, 2007, at 1:24 AM, Wesley Smith wrote:
>
> Hi everyone,
> There was some talk a few weeks ago about vertex skinning.  Here's a
> patch that demos the technique.  It's a little hairy, especially the
> vertex shader, but it does work.  This patch is not completely error
> free yet.  For some reason the vertex interpolation is squishing
> segments together and I haven't figured out why, but I think the idea
> still comes across.
>
> Here's how it works:
> I've divided the mesh into 5 sections, each controlled by the position
> and rotation (modelview matrix without the scale) of a gridshape.  I
> generated a cylindrical mesh and assigned each vertex to a section
> (bone in the vertex skinning terminology) and a weight.  The weight
> says how much a given vertex is affected by a particular bone.
> Getting all this data into a vertex shader is a bit tricky.  Here I
> put the weights in the texture coordinate matrix and the bone
> assignment in the tangents matrix.  This choice was for convenience
> but is not the only way to do it.
>
> The trickiest part of this whole business is getting the modelview
> matrix  for each segment ( aka the bone matrices) into the shader.  To
> conserve space, only the rotation and translation portions of the
> matrix are sent which ends up being a 3x4 matrix.  In the shader,
> these are stored as an array of vec4s.  For convenience, I actually
> send the transpose of the 3x4 bone matrix so that a row of the matrix
> is stored in a single vec4.  Again, this isn't the only way to go.  In
> the shader, I build a modelview matrix from this data and use it to
> find a new position for the vertex.
>
> Theoretically, all of this data could be generated in Maya.  Maya has
> really nice tools for building skins and bones for a mesh, but the
> m********* f********* has really lame export facilities.  I tried
> about half a dozen plugins that supposedly export skin and bone data
> but none of them worked.  If someone knows how to do this, I would be
> most grateful to know how.
>
> Here's the link.
> http://www.mat.ucsb.edu/~whsmith/PlaydoughMesh.zip
>
> best,
> wes
>
> v a d e //
>
> www.vade.info
> abstrakt.vade.info
>
>
>
>
>
>
>


On Jan 2, 2007, at 2:29 AM, Wesley Smith wrote:

> Don't hit init mesh then. It gets called on loadbang anyway. Just

> turn on the metro. I was getting alot of crashes as well with this

> patch but it worked on my macintel imac with jitter b3.

> Don't hit init mesh then.  It gets called on loadbang anyway.  Just
> turn on the metro.  I was getting alot of crashes as well with this
> patch but it worked on my macintel imac with jitter b3.
>
> wes

This thread is so sick, bump (did I use that word right?) Y'all should check out those shaders n patches above. good work boys.

Playdough Mesh