Extension/Reduction of a vascular segment

[SMSadat98]

Hello @hkjeldsberg ,

I want to extend/reduce a certain portion of the vascular geometry lengthwise, while preserving (if possible) its natural curvature or centerline path. Is it possible to implement such a feature?

Adding to that, I would like to bring up a previously discussed issue. While changing the bend severely, the length of the vascular geometry changes. Is it possible to keep the length unchanged while changing the bend or will this issue be addressed/worked on later?

Best Regards,
Sadat

[hkjeldsberg]

Hi @SMSadat98 ,

Great feature suggestion! For extension or reduction of relatively straight segments, I think manipulate_bend would do the trick. Attached is two examples with extension and reduction of a model provided by you previously. Using alpha=0 and beta=+/-0.4, respectively.

For manipulation of longer curved segments, manipulate_bend could probably still be used with a good combination of parameters alpha and beta, but might introduce geometric artifacts.
Alternatively, for (1) reduction the model can simply be clipped for the desired reduction, followed by translation (and rotation) of the remaining geometry. For (2) extension, the model could either be extended based on the direction of the centerline tangent, or be some sort of extrapolation based on the centerline curvature. I'd be happy to hear what you think!

As for the second feature/issue, this is something we have wanted to implement from before (see issue #48), but his has not been implemented yet. Although this is not prioritized at the moment, it is something that can be investigated in the near future if there is interest.

Best,
Henrik

[SMSadat98]

Hello @hkjeldsberg ,

Thank you for the idea! The extension works just fine with alpha/beta values. The reduction does work, although needs a number of trial-and-error runs and indeed, it introduces artifacts in most cases.

For extension method, in my opinion, extension based on centerline tangent would be a better approach. That way the new centerline curvature would stay true to the original curvature. Additionally, simple bending operation can be performed after the extension to get any desired curvature.

I hope the length preservation during bending operation gets implemented in the near future as it will retain the patient specificity even more!

Best regards,
Sadat