Hi, I'm a complete novice at the field of Dipy so, first, thank you very much to all of you. I would like to exploit Dipy tractography tools to draw my own data (Not DWI), but I have some problem about the fiber directions representation. I work with 3D images of heart muscle tissue, and I developed a simple code that extract the fibers orientation by means of a Structure Tensor Analysis. So, I have a 3d matrix 'R' (numpy.ndarray); every R(z, y, x) element contains: - three eigenvalues (3x1 matrx) - three R3 eigenvectors (3x3 matrix) - others informations (for example, the Fractional Anisotropy, useful for the stop criterium) In the attached, there is a one-frame example (only one XY plane analyzed) of the orientations maps, plotted with matplotlib and mayavi. I'm trying to understand how to format my data to generate the streamlines. I have reproduced some examples. Here ( http://nipy.org/dipy/examples_built/tracking_quick_start.html#example-tracki...) i find that csd_peaks contains the vectors informations (the source of the tractography process?) while here ( http://nipy.org/dipy/examples_built/reconst_dti.html#example-reconst-dti) seems that tenfit contains the same vector field. I'm reading also the documentation about dipy.tracking.local.LocalTracking and dipy.tracking.local.DirectionGetter. How I can merge my data with the Dipy structures, to generate and display my streamlines? I'am looking forward to your reply. Thank you very much. Francesco Giardini -- Dr. Francesco Giardini (giardini@lens.unifi.it) LENS - European Laboratory for Non-linear Spectroscopy Via Nello Carrara 1, 50019 Sesto Fiorentino (FI), Italy University of Florence - Biomedical Engineering Tel. 055 457 2477 (off.) http://www.lens.unifi.it