Hi John and David,

Thanks a lot for your reply! Yes I'm thinking to move from Caret to Workbench 
since most of the time we use wb_command a lot and it makes sense to keep our 
tools up-to-date and consistent.


Just want to clarify: the weights (last 3 columns) of the vertices (indexed by 
the first 3 columns) are decided by the distance from the 3 vertices of SOURCE 
to the vertex of TARGET? If so, maybe that's the reason why why the sum of 
weights is not one for each vertex of TARGET?


So the reason why I'm looking at deformation maps is that I'm trying to figure 
out a way to quantify the deformation from native space to fs_LR at each vertex 
on the surface (32k fs_LR atlas surface). Could you give me any suggestion?

________________________________
From: David Van Essen <vanes...@wustl.edu>
Sent: Friday, October 20, 2017 3:41:11 PM
To: Caret, SureFit, and SuMS software users; tony han
Subject: Re: [caret-users] info in the deformation maps

Hi Tony et al.

John’s explanation regarding deformation map files is correct.  Here, I’m 
drawing to your attention the fact that Connectome Workbench (and wb_command) 
provides improved methods for mapping from one surface mesh that has been 
registered to another (see below).  Depending on your use case scenario, you 
(and others) may decide to stick with Caret and its deformation maps (even 
though Caret is no longer under active development). Or you may find it 
advantageous to switch to wb_command for future analyses, as it has become more 
 powerful and flexible, and is still under active development 
(https://www.humanconnectome.org/software/connectome-workbench).

wb_command -label-resample
wb_command -metric-resample
  <current-sphere> - a sphere surface with the mesh that the metric is
         currently on
      <new-sphere> - a sphere surface that is in register with <current-sphere>
         and has the desired output mesh
      <method> - the method name
The <method> argument must be one of the following:
      ADAP_BARY_AREA
      BARYCENTRIC
as explained in the command-line usage instructions

On Oct 20, 2017, at 2:36 PM, Harwell, John 
<jharw...@wustl.edu<mailto:jharw...@wustl.edu>> wrote:

Hello,

You are correct, it is not an affine matrix.   A description of the file’s 
content is available at 
http://brainvis.wustl.edu/CaretHelpAccount/caret5_help/file_formats/file_formats.html#deformationMapFile.

Essentially, the deformation map file defines a resampling of one surface 
triangular mesh to another.  For each vertex in the target surface, it 
identifies the corresponding location in the source surface using barycentric 
coordinates.  A barycentric coordinate contains three vertex indices that form 
a triangle and the weights define the location within the triangle.

John H

On Oct 20, 2017, at 1:00 PM, tony han 
<oktony...@hotmail.com<mailto:oktony...@hotmail.com>> wrote:

Hi,

I notice that there are 6 columns of data stored in the deformation map 
(actually it's 7 but the first one looks like the indices). So what are these 
columns? It doesn't look like affine matrices? Thanks!

Best,
Tony
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