[vtkusers] Volume rendering produces rough surface at clipping plane

[Andras Lasso]

This is awesome! Thanks a lot for implementing this. It will greatly improve clipped volume visualization.

Andras

From: Sankhesh Jhaveri <sankhesh.jhaveri at kitware.com>
Sent: Wednesday, August 29, 2018 9:49 AM
To: Andras Lasso <lasso at queensu.ca>
Cc: vtkusers at vtk.org
Subject: Re: [vtkusers] Volume rendering produces rough surface at clipping plane


Hi Andras,

!4627<https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgitlab.kitware.com%2Fvtk%2Fvtk%2Fmerge_requests%2F4627&data=02%7C01%7Classo%40queensu.ca%7C1b0e2ad2d9874241678b08d60db63cd7%7Cd61ecb3b38b142d582c4efb2838b925c%7C1%7C0%7C636711473694883358&sdata=9QSPhtudVqpDJdcEPxqZWO9hV0iqEG%2Fmt58KwRe9w8I%3D&reserved=0> implements a mode in vtkVolumeProperty that lets you use custom intensity values for voxels in the clipped space when computing gradients at the clip face.

Best,
Sankhesh
​

On Fri, Nov 3, 2017 at 10:48 AM Andras Lasso <lasso at queensu.ca<mailto:lasso at queensu.ca>> wrote:
Hi all,

I’m working on visualizing cardiac images using volume rendering. I need to cut into the volume to see surfaces inside the heart, which works quite well by using clipping planes of the volume mapper. The only problem is that that surface at the cut plane looks very rough, which makes it difficult to distinguish from actual endocardial surfaces. If I “cut” the volume by setting voxel values outside the clipping box to “empty” (-1000 = air intensity value) then the cut surface looks nice – smooth and flat. See example for both cutting method in the attached files.

Is there a way to change volume renderer to get smooth cut surfaces (the same look as we get by setting outside voxels to “empty” values)?

Andras

---

See full resolution images and more examples here:
https://1drv.ms/f/s!Arm_AFxB9yqHsOsClG_QsMx-4sh8rg<https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2F1drv.ms%2Ff%2Fs!Arm_AFxB9yqHsOsClG_QsMx-4sh8rg&data=02%7C01%7Classo%40queensu.ca%7C1b0e2ad2d9874241678b08d60db63cd7%7Cd61ecb3b38b142d582c4efb2838b925c%7C1%7C0%7C636711473694883358&sdata=Kv2zau7vHuPxMEosN89SF1IGYjCwCKQk0lrngO9Tnzg%3D&reserved=0>

CT volume can be downloaded from here:
http://slicer.kitware.com/midas3/download/item/292309/CTA-cardio.nrrd<https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fslicer.kitware.com%2Fmidas3%2Fdownload%2Fitem%2F292309%2FCTA-cardio.nrrd&data=02%7C01%7Classo%40queensu.ca%7C1b0e2ad2d9874241678b08d60db63cd7%7Cd61ecb3b38b142d582c4efb2838b925c%7C1%7C0%7C636711473694893363&sdata=atKizvUvC92hjztLus1b6ybp8OrwZJh6%2B599fLLctbU%3D&reserved=0>

________________________
Andras Lasso, PhD
Senior Research Engineer, Associate Director (Engineering)
Laboratory for Percutaneous Surgery
School of Computing, Queen's University
Kingston, ON, Canada

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Sankhesh Jhaveri
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