fos-pyside tractography not correct

[Eleftherios Garyfallidis]

Hello,

This is question is for Stephan but I am sure it can be interesting for others as well.

I started working on fos-pyside and I am interested on example tractography.py. However when I visualize it the tracks of the fornix are not correctly positioned. This is very easy to check with fvtk.lines or from Fos (InteractiveCurves). So what is the problem with this example?

Also perhaps the connectivity is not necessary for tracks, orbits etc. Are you sure we need this? Let me know what you think.

Best wishes,
Eleftherios

[Stephan Gerhard]

Hi,

Indeed the display of the fornix is wrong, havent noticed this so far.

The data should be correct, since I think I just copied the example
data from dipy,
but this needs to be checked.

The orientation (the affine of the region) is also not set to the
affine of the trackvis
file, but this should only impact the orientation of the axes.

Can you recognize how the ordering changed, because it looks somewhat similar.
It could well be that I made a mistake when constructing the connectivity array.
Can you check if this is correct?

> Also perhaps the connectivity is not necessary for tracks, orbits etc. Are
> you sure we need this? Let me know what you think.

You are right. Storing the connectivity always is more general, but very memory
inefficient because it is implicit for tracks, i.e. it could use the
OpenGL LINE_STRIP primitives.
The relevant bit is the Skeleton Actor in fos-pyside. We could have
another Actor that
assumes a segmentation of the coordinate position arrays, i.e. which
would not need
the connectivity information, but information where segments (e.g.
tracks) start and stop.

Stephan

[Eleftherios Garyfallidis]

Okay I fixed that. You were shifting every track to its center. Now do you have an example were picking works with pyside? And if yes which?

[Stephan Gerhard]

The microcircuit or skeleton examples should show picking. You should
be able to pick
with Ctrl-Click on the lines.
Stephan