Morphing of the Sacrum

Hello AnyBody Team,

I currently want to morph the pelvis and sacrum in the AMMR to patient-MRI stl-files.
For the pelvis, the step-by-step instructions from the AnyBody Tutorials worked fine.
However, the sacrum does not change at all, despite several attempts. As with the pelvis morphing, I tried to include a custom scaling function for the sacrum:

HumanModel.Scaling.GeometricalScaling = {
SacrumSeg = {
#include "MyScalingFunctionSacrum.any"
ScaleFunction.Custom = &MyScalingFunctionSacrum.STLTransformSacrum;

The "STLTransformSacrum" is a "AnyFunTransform3DSTL" with a "AnyFunTransform3DRBF" and here a "AnyFunTransform3DLin2" as PreTransforms.
The model loads successfully, but does not adapt the sacrum. I have noticed that in the pelvis segment of the AMMR, there is also a DrwSacrum in addition to the DrwPelvis. So I tried to add the scaling function to the pelvis segment as well, but without success.

What is the right way to morph the sacrum into an individual stl file?

Thank you very much!

Kind regards,


Hi Ina,

I think your code does not look bad, I have an example here that looks similar:

HumanModel.Scaling.GeometricalScaling = {
  Pelvis.ScaleFunction.Custom = &Main.MyScalingFunctions.Pelvis.Transform;
  SacrumSeg.ScaleFunction.Custom = &Main.MyScalingFunctions.Pelvis.Transform;

Something else must be a problem - it's hard to say without seeing the rest.

You can also notice that I combined pelvis and sacrum scaling into the same function, since they are defined in the same ref. frame.

Kind regards, Pavel

Hello Pavel,

thank you for your quick response.

My "MyScalingFunctions" are structured as instructed in the Morphing-Tutorials with the Input-reference of the AnyFunTransform3DSTL to the Pelvis or Sacrum FileNames of the Source- and Target AnySurfSTLs.

Could you maybe specify how you combined the pelvis and sacrum scaling into the same function?

Kind regards,

I construct an RBF transformation from the landmarks of both pelvis and sacrum (i stop before STLRBF).

And regarding the details - I think we will need to see the code, the textual description can be very ambiguous.

Kind regards,

Hello Parvel,

the use of only RBF transformation for pelvis and sacrum landmarks in combination with your code example already worked for my model as well!
Thank you very much for your help!

Kind regards,