Model Registration Using Singular Points

Operating system: Windows 10 build 17763.775
Slicer version: 4.10.2

Expected behavior: I currently have 2 main transforms within my scene: NeedleToReference and PhantomToReference. Within the NeedleToReference transform, I have another transformation that maps the NeedleTipToNeedle. I would like to place some spherical models inside the phantom. As I can locate the center of the sphere position within the phantom using the needle tip I was thinking of placing fiducial points in 3D space using the needle tip, finding the linear transform between the marker and my phantom tracker, and placing a spherical model in the Transform Hierarchy in the Data module.

Actual behavior: I am currently unsure about how to calculate the transformation between the fiducial point relative to the phantom position sensor.

Any help on the issue would be greatly appreciated!

The process for landmark-based object registration using a tracked stylus is described in detail in SlicerIGT tutorials (“Pivot calibration” and “Landmark registration”).