Affine matrices (Insight format) with tag MatrixOffsetTransformBase_double_3_3 cannot be loaded into Slicer anymore

Support
1

After running ANTs buildtemplateparallel.sh script to create a template from several of our MRI scans, we receive multiple pairs of linear-affine matrices (.txt) and deformation fields (.nii.gz) that I want to load into Slicer for visualization&sanity checking.
Expected behaviour: drag&drop the .txt affine matrix file into Slicer, and the transform gets loaded.
Actual behaviour: the matrix transformation tag is not recognized by Slicer, as described in the error log:
“Could not create an instance of “MatrixOffsetTransformBase_double_3_3”
The usual cause of this error is not registering the transform with TransformFactory”.
I have to manually change the tag “MatrixOffsetTransformBase_double_3_3” to “AffineTransform_double_3_3”, then it gets loaded correctly.

The full .txt content prior to the manual change is the following:
#Insight Transform File V1.0
#Transform 0
Transform: MatrixOffsetTransformBase_double_3_3
Parameters: 1.128638506675143 -0.018901975572667252 0.003732574598088019 0.05839336218683332 0.9249441890918595 0.012912029188555302 -0.0007861952948720328 -0.09741033293018547 1.2857967364097567 3.45194891887621 -1.6884605061223075 8.428466991955123
FixedParameters: -2.1885326956456645 -15.230008711557268 -15.255627879066756

Previously (Slicer versions <4.8), I was able to load these files without error, now it doesn’t work anymore. Could you please advise?

2

There were 1-2 days recently when this was broken in the nightly version. It should work well in the current nightly version.

3

Indeed, commit r27035 fixed the regression