# Would like to develop a method to identify cranial openings in surface model via ITK-Snap... must I synthesize a Dicom/Analyze image?
**URL:** https://discourse.itk.org/t/would-like-to-develop-a-method-to-identify-cranial-openings-in-surface-model-via-itk-snap-must-i-synthesize-a-dicom-analyze-image/7631
**Category:** Algorithms
**Created:** [September 16, 2025, 1:29pm UTC](https://discourse.itk.org/t/would-like-to-develop-a-method-to-identify-cranial-openings-in-surface-model-via-itk-snap-must-i-synthesize-a-dicom-analyze-image/7631 "2025-09-16T13:29:19Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@MichelODU](https://discourse.itk.org/u/MichelODU)
#### Post date: [September 16, 2025, 1:29pm UTC](https://discourse.itk.org/t/would-like-to-develop-a-method-to-identify-cranial-openings-in-surface-model-via-itk-snap-must-i-synthesize-a-dicom-analyze-image/7631/1 "2025-09-16T13:29:20Z")
Dear ITK users,
I would like to develop a method to identify cranial openings in surface model via ITK-Snap… must I synthesize a Dicom/Analyze image via ITK first? Is there a way to do this in a manner that precisely spans the volume of the surface model? I need to produce a labeled mapping of the cranial openings, and my intuition tells me that I simply cannot do this with only the surface model. If so, is it possible to load the surface model while retaining the vertex coordinates, to produce an isotropic CT-like image that encapsulates it? (I do not have access to the original CT scan that was used to produce the surface model…)
I tried to ask this on ITK-Snap users list, but my membership has not been approved yet. Thanks for your consideration.
Cheers, Michel
---
### Author:  [@dzenanz](https://discourse.itk.org/u/dzenanz)
#### Post date: [September 16, 2025, 2:35pm UTC](https://discourse.itk.org/t/would-like-to-develop-a-method-to-identify-cranial-openings-in-surface-model-via-itk-snap-must-i-synthesize-a-dicom-analyze-image/7631/2 "2025-09-16T14:35:09Z")
If you need a one-time conversion, [3D Slice](https://www.slicer.org/)r can import polygonal models into its Segmentations module, and convert it into a label image. For that you do need a “base image”, which can be created via resample module (where you can specify origin, spacing, direction, size).
Also, what do you mean by “identify cranial openings”? If you mean topological holes, I believe that can be done in polygonal meshes, though ITK is not the library for it.
---
### Author:  [@zivy](https://discourse.itk.org/u/zivy)
#### Post date: [September 16, 2025, 3:14pm UTC](https://discourse.itk.org/t/would-like-to-develop-a-method-to-identify-cranial-openings-in-surface-model-via-itk-snap-must-i-synthesize-a-dicom-analyze-image/7631/3 "2025-09-16T15:14:14Z")
Hello Michel,
Possibly look at the [vtkPolyDataToImageStencil](https://www.vtk.org/doc/nightly/html/classvtkPolyDataToImageStencil.html) for mesh to volume conversion (see the [Python example](https://examples.vtk.org/site/Python/PolyData/PolyDataToImageDataStencil/)).
---
### Author:  [@MichelODU](https://discourse.itk.org/u/MichelODU)
#### Post date: [September 16, 2025, 3:19pm UTC](https://discourse.itk.org/t/would-like-to-develop-a-method-to-identify-cranial-openings-in-surface-model-via-itk-snap-must-i-synthesize-a-dicom-analyze-image/7631/4 "2025-09-16T15:19:52Z")
Hi Dzenan,
thanks for your reply. By cranial openings, I designate cranial foramina, such as foramen magnum, foramen rotundum, and so on. Not topological holes in the triangulated surface. I will suggest your solution to my student. Cheers, Michel
---
### Author:  [@MichelODU](https://discourse.itk.org/u/MichelODU)
#### Post date: [September 16, 2025, 3:20pm UTC](https://discourse.itk.org/t/would-like-to-develop-a-method-to-identify-cranial-openings-in-surface-model-via-itk-snap-must-i-synthesize-a-dicom-analyze-image/7631/5 "2025-09-16T15:20:34Z")
Hi Ziv,
it’s nice to see you in this forum. Thanks for your kind contribution. I’ll have my student look into this option too. Cheers,
Michel