vtkCutter leaves "gaps"

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vtkCutter leaves "gaps"

Gerrick Bivins

Hi All,

I’ve run into a strange problem where with some of my datasets, vtkCutter is leaving “gaps” in the output polydata.

For example, if I use a plane as the implicit function the attached image shows the result.

Anyone seen this kind of  behavior before?

Is there some setting on the vtkCutter that is perhaps causing this?

 

Gerrick

 

 

 

DecisionSpace® 5000.8.3 Now Available

 


This e-mail, including any attached files, may contain confidential and privileged information for the sole use of the intended recipient. Any review, use, distribution, or disclosure by others is strictly prohibited. If you are not the intended recipient (or authorized to receive information for the intended recipient), please contact the sender by reply e-mail and delete all copies of this message.

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Re: vtkCutter leaves "gaps"

Gerrick Bivins

I realized I sent this at a time when most people were probably offline.

Just a “BUMP” in case this got missed.

Anyone have any ideas here?

Gerrick

From: [hidden email] [mailto:[hidden email]] On Behalf Of Gerrick Bivins
Sent: Monday, November 25, 2013 8:33 AM
To: '[hidden email]'
Subject: [vtkusers] vtkCutter leaves "gaps"

 

Hi All,

I’ve run into a strange problem where with some of my datasets, vtkCutter is leaving “gaps” in the output polydata.

For example, if I use a plane as the implicit function the attached image shows the result.

Anyone seen this kind of  behavior before?

Is there some setting on the vtkCutter that is perhaps causing this?

 

Gerrick

 

 

 

DecisionSpace® 5000.8.3 Now Available

 


This e-mail, including any attached files, may contain confidential and privileged information for the sole use of the intended recipient. Any review, use, distribution, or disclosure by others is strictly prohibited. If you are not the intended recipient (or authorized to receive information for the intended recipient), please contact the sender by reply e-mail and delete all copies of this message.


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Re: vtkCutter leaves "gaps"

Bill Lorensen
I do not see the attachment/



On Fri, Dec 6, 2013 at 12:50 PM, Gerrick Bivins <[hidden email]> wrote:

I realized I sent this at a time when most people were probably offline.

Just a “BUMP” in case this got missed.

Anyone have any ideas here?

Gerrick

From: [hidden email] [mailto:[hidden email]] On Behalf Of Gerrick Bivins
Sent: Monday, November 25, 2013 8:33 AM
To: '[hidden email]'
Subject: [vtkusers] vtkCutter leaves "gaps"

 

Hi All,

I’ve run into a strange problem where with some of my datasets, vtkCutter is leaving “gaps” in the output polydata.

For example, if I use a plane as the implicit function the attached image shows the result.

Anyone seen this kind of  behavior before?

Is there some setting on the vtkCutter that is perhaps causing this?

 

Gerrick

 

 

 

DecisionSpace® 5000.8.3 Now Available

 


This e-mail, including any attached files, may contain confidential and privileged information for the sole use of the intended recipient. Any review, use, distribution, or disclosure by others is strictly prohibited. If you are not the intended recipient (or authorized to receive information for the intended recipient), please contact the sender by reply e-mail and delete all copies of this message.


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--
Unpaid intern in BillsBasement at noware dot com

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Re: vtkCutter leaves "gaps"

David Gobbi
Hi Gerrick,

The cutter algorithm is fairly straightforward, it just creates a new point along each edge that is intersected by the plane.  Then it uses its knowledge about the connectivity of the original cells to join the new points together to create new cells.

The only problem I've ever seen with vtkCutter is the fact that its locator is limited by numerical precision: it might think two cells share an edge when in fact the edges are just very, very close to each other.  But the result of this is that gaps are closed, not created.

In response to the question about whether I've ever seen vtkCutter create gaps where no gaps exist in the original data, I'd have to say no.  That's not to say that it could never happen.  The vtkCutter delegates the "cutting" to the Contour methods of the various cell classes, so it is possible that your data uses a cell type with a buggy Contour implementation.  If that is the case, it would be good to know the details of your data so that someone can investigate, but my first suspicion is that the gaps are present in your original data.

  David


On Fri, Dec 6, 2013 at 11:13 AM, Bill Lorensen <[hidden email]> wrote:
I do not see the attachment/



On Fri, Dec 6, 2013 at 12:50 PM, Gerrick Bivins <[hidden email]> wrote:

I realized I sent this at a time when most people were probably offline.

Just a “BUMP” in case this got missed.

Anyone have any ideas here?

Gerrick

From: [hidden email] [mailto:[hidden email]] On Behalf Of Gerrick Bivins
Sent: Monday, November 25, 2013 8:33 AM
To: '[hidden email]'
Subject: [vtkusers] vtkCutter leaves "gaps"

 

Hi All,

I’ve run into a strange problem where with some of my datasets, vtkCutter is leaving “gaps” in the output polydata.

For example, if I use a plane as the implicit function the attached image shows the result.

Anyone seen this kind of  behavior before?

Is there some setting on the vtkCutter that is perhaps causing this?

 

Gerrick

 

 

 

DecisionSpace® 5000.8.3 Now Available

 


This e-mail, including any attached files, may contain confidential and privileged information for the sole use of the intended recipient. Any review, use, distribution, or disclosure by others is strictly prohibited. If you are not the intended recipient (or authorized to receive information for the intended recipient), please contact the sender by reply e-mail and delete all copies of this message.



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Re: vtkCutter leaves "gaps"

Gerrick Bivins

Bill,

For some reason it took a couple of tries to get that one through. Maybe attachement size was too big but it made it to the nabble list:

http://vtk.1045678.n5.nabble.com/vtkCutter-leaves-quot-gaps-quot-tt5724617.html

 

David,

Right, it feels like a bug in polyhedron cells.

My data was pretty simple, a block with poly cells a with varying thickness and width.

Definitely no holes. I probably can’t send it along but

note there was just recently a post (probably minutes before my “BUMP” made it through) about a very similar issue:

http://vtk.1045678.n5.nabble.com/Bug-in-slice-and-clip-for-mesh-containing-VTK-POLYHEDRON-cells-tt5724879.html

It also has a problematic model attached.

 

Gerrick

 

 

From: David Gobbi [mailto:[hidden email]]
Sent: Friday, December 06, 2013 12:42 PM
To: Gerrick Bivins
Cc: Bill Lorensen; [hidden email]
Subject: Re: [vtkusers] vtkCutter leaves "gaps"

 

Hi Gerrick,

 

The cutter algorithm is fairly straightforward, it just creates a new point along each edge that is intersected by the plane.  Then it uses its knowledge about the connectivity of the original cells to join the new points together to create new cells.

 

The only problem I've ever seen with vtkCutter is the fact that its locator is limited by numerical precision: it might think two cells share an edge when in fact the edges are just very, very close to each other.  But the result of this is that gaps are closed, not created.

 

In response to the question about whether I've ever seen vtkCutter create gaps where no gaps exist in the original data, I'd have to say no.  That's not to say that it could never happen.  The vtkCutter delegates the "cutting" to the Contour methods of the various cell classes, so it is possible that your data uses a cell type with a buggy Contour implementation.  If that is the case, it would be good to know the details of your data so that someone can investigate, but my first suspicion is that the gaps are present in your original data.

 

  David

 

On Fri, Dec 6, 2013 at 11:13 AM, Bill Lorensen <[hidden email]> wrote:

I do not see the attachment/

 

On Fri, Dec 6, 2013 at 12:50 PM, Gerrick Bivins <[hidden email]> wrote:

I realized I sent this at a time when most people were probably offline.

Just a “BUMP” in case this got missed.

Anyone have any ideas here?

Gerrick

From: [hidden email] [mailto:[hidden email]] On Behalf Of Gerrick Bivins
Sent: Monday, November 25, 2013 8:33 AM
To: '[hidden email]'
Subject: [vtkusers] vtkCutter leaves "gaps"

 

Hi All,

I’ve run into a strange problem where with some of my datasets, vtkCutter is leaving “gaps” in the output polydata.

For example, if I use a plane as the implicit function the attached image shows the result.

Anyone seen this kind of  behavior before?

Is there some setting on the vtkCutter that is perhaps causing this?

 

Gerrick

 

 

 

DecisionSpace® 5000.8.3 Now Available

 


This e-mail, including any attached files, may contain confidential and privileged information for the sole use of the intended recipient. Any review, use, distribution, or disclosure by others is strictly prohibited. If you are not the intended recipient (or authorized to receive information for the intended recipient), please contact the sender by reply e-mail and delete all copies of this message.

 


_______________________________________________
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Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html

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Re: vtkCutter leaves "gaps"

David Gobbi
Hi Gerrick,

If it's polyhedral cells, then yes, a bug is a definite possibility.  Gathering info from other poly users is the right way to go.  Sorry that I can't be of more help, but I haven't used poly cells myself.

  David


On Fri, Dec 6, 2013 at 12:47 PM, Gerrick Bivins <[hidden email]> wrote:

Bill,

For some reason it took a couple of tries to get that one through. Maybe attachement size was too big but it made it to the nabble list:

http://vtk.1045678.n5.nabble.com/vtkCutter-leaves-quot-gaps-quot-tt5724617.html

 

David,

Right, it feels like a bug in polyhedron cells.

My data was pretty simple, a block with poly cells a with varying thickness and width.

Definitely no holes. I probably can’t send it along but

note there was just recently a post (probably minutes before my “BUMP” made it through) about a very similar issue:

http://vtk.1045678.n5.nabble.com/Bug-in-slice-and-clip-for-mesh-containing-VTK-POLYHEDRON-cells-tt5724879.html

It also has a problematic model attached.

 

Gerrick

 

 

From: David Gobbi [mailto:[hidden email]]
Sent: Friday, December 06, 2013 12:42 PM
To: Gerrick Bivins
Cc: Bill Lorensen; [hidden email]
Subject: Re: [vtkusers] vtkCutter leaves "gaps"

 

Hi Gerrick,

 

The cutter algorithm is fairly straightforward, it just creates a new point along each edge that is intersected by the plane.  Then it uses its knowledge about the connectivity of the original cells to join the new points together to create new cells.

 

The only problem I've ever seen with vtkCutter is the fact that its locator is limited by numerical precision: it might think two cells share an edge when in fact the edges are just very, very close to each other.  But the result of this is that gaps are closed, not created.

 

In response to the question about whether I've ever seen vtkCutter create gaps where no gaps exist in the original data, I'd have to say no.  That's not to say that it could never happen.  The vtkCutter delegates the "cutting" to the Contour methods of the various cell classes, so it is possible that your data uses a cell type with a buggy Contour implementation.  If that is the case, it would be good to know the details of your data so that someone can investigate, but my first suspicion is that the gaps are present in your original data.

 

  David

 

On Fri, Dec 6, 2013 at 11:13 AM, Bill Lorensen <[hidden email]> wrote:

I do not see the attachment/

 

On Fri, Dec 6, 2013 at 12:50 PM, Gerrick Bivins <[hidden email]> wrote:

I realized I sent this at a time when most people were probably offline.

Just a “BUMP” in case this got missed.

Anyone have any ideas here?

Gerrick

From: [hidden email] [mailto:[hidden email]] On Behalf Of Gerrick Bivins
Sent: Monday, November 25, 2013 8:33 AM
To: '[hidden email]'
Subject: [vtkusers] vtkCutter leaves "gaps"

 

Hi All,

I’ve run into a strange problem where with some of my datasets, vtkCutter is leaving “gaps” in the output polydata.

For example, if I use a plane as the implicit function the attached image shows the result.

Anyone seen this kind of  behavior before?

Is there some setting on the vtkCutter that is perhaps causing this?

 

Gerrick

 

 

 

DecisionSpace® 5000.8.3 Now Available

 


This e-mail, including any attached files, may contain confidential and privileged information for the sole use of the intended recipient. Any review, use, distribution, or disclosure by others is strictly prohibited. If you are not the intended recipient (or authorized to receive information for the intended recipient), please contact the sender by reply e-mail and delete all copies of this message.

 



_______________________________________________
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Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html

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Re: vtkCutter leaves "gaps"

Gerrick Bivins

Ok. I tried to  “Tetrahedralize” the dataset before using the cutter, and it produced

a “gapless” slice in paraview.

It loses the structure of the cells (everything is triangles obviously) but at least it doesn’t drop elements.

 

What filter does “Tetrahedralize” map to in VTK?

 

Gerrick

From: David Gobbi [mailto:[hidden email]]
Sent: Friday, December 06, 2013 2:01 PM
To: Gerrick Bivins
Cc: Bill Lorensen; [hidden email]
Subject: Re: [vtkusers] vtkCutter leaves "gaps"

 

Hi Gerrick,

 

If it's polyhedral cells, then yes, a bug is a definite possibility.  Gathering info from other poly users is the right way to go.  Sorry that I can't be of more help, but I haven't used poly cells myself.

 

  David

 

On Fri, Dec 6, 2013 at 12:47 PM, Gerrick Bivins <[hidden email]> wrote:

Bill,

For some reason it took a couple of tries to get that one through. Maybe attachement size was too big but it made it to the nabble list:

http://vtk.1045678.n5.nabble.com/vtkCutter-leaves-quot-gaps-quot-tt5724617.html

 

David,

Right, it feels like a bug in polyhedron cells.

My data was pretty simple, a block with poly cells a with varying thickness and width.

Definitely no holes. I probably can’t send it along but

note there was just recently a post (probably minutes before my “BUMP” made it through) about a very similar issue:

http://vtk.1045678.n5.nabble.com/Bug-in-slice-and-clip-for-mesh-containing-VTK-POLYHEDRON-cells-tt5724879.html

It also has a problematic model attached.

 

Gerrick

 

 

From: David Gobbi [mailto:[hidden email]]
Sent: Friday, December 06, 2013 12:42 PM
To: Gerrick Bivins
Cc: Bill Lorensen; [hidden email]
Subject: Re: [vtkusers] vtkCutter leaves "gaps"

 

Hi Gerrick,

 

The cutter algorithm is fairly straightforward, it just creates a new point along each edge that is intersected by the plane.  Then it uses its knowledge about the connectivity of the original cells to join the new points together to create new cells.

 

The only problem I've ever seen with vtkCutter is the fact that its locator is limited by numerical precision: it might think two cells share an edge when in fact the edges are just very, very close to each other.  But the result of this is that gaps are closed, not created.

 

In response to the question about whether I've ever seen vtkCutter create gaps where no gaps exist in the original data, I'd have to say no.  That's not to say that it could never happen.  The vtkCutter delegates the "cutting" to the Contour methods of the various cell classes, so it is possible that your data uses a cell type with a buggy Contour implementation.  If that is the case, it would be good to know the details of your data so that someone can investigate, but my first suspicion is that the gaps are present in your original data.

 

  David

 

On Fri, Dec 6, 2013 at 11:13 AM, Bill Lorensen <[hidden email]> wrote:

I do not see the attachment/

 

On Fri, Dec 6, 2013 at 12:50 PM, Gerrick Bivins <[hidden email]> wrote:

I realized I sent this at a time when most people were probably offline.

Just a “BUMP” in case this got missed.

Anyone have any ideas here?

Gerrick

From: [hidden email] [mailto:[hidden email]] On Behalf Of Gerrick Bivins
Sent: Monday, November 25, 2013 8:33 AM
To: '[hidden email]'
Subject: [vtkusers] vtkCutter leaves "gaps"

 

Hi All,

I’ve run into a strange problem where with some of my datasets, vtkCutter is leaving “gaps” in the output polydata.

For example, if I use a plane as the implicit function the attached image shows the result.

Anyone seen this kind of  behavior before?

Is there some setting on the vtkCutter that is perhaps causing this?

 

Gerrick

 

 

 

DecisionSpace® 5000.8.3 Now Available

 


This e-mail, including any attached files, may contain confidential and privileged information for the sole use of the intended recipient. Any review, use, distribution, or disclosure by others is strictly prohibited. If you are not the intended recipient (or authorized to receive information for the intended recipient), please contact the sender by reply e-mail and delete all copies of this message.

 

 


_______________________________________________
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Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html

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Re: vtkCutter leaves "gaps"

David Gobbi
A "Tesselator" filter, I think?


On Mon, Dec 9, 2013 at 9:43 AM, Gerrick Bivins <[hidden email]> wrote:

Ok. I tried to  “Tetrahedralize” the dataset before using the cutter, and it produced

a “gapless” slice in paraview.

It loses the structure of the cells (everything is triangles obviously) but at least it doesn’t drop elements.

 

What filter does “Tetrahedralize” map to in VTK?

 

Gerrick

From: David Gobbi [mailto:[hidden email]]
Sent: Friday, December 06, 2013 2:01 PM


To: Gerrick Bivins
Cc: Bill Lorensen; [hidden email]
Subject: Re: [vtkusers] vtkCutter leaves "gaps"

 

Hi Gerrick,

 

If it's polyhedral cells, then yes, a bug is a definite possibility.  Gathering info from other poly users is the right way to go.  Sorry that I can't be of more help, but I haven't used poly cells myself.

 

  David

 

On Fri, Dec 6, 2013 at 12:47 PM, Gerrick Bivins <[hidden email]> wrote:

Bill,

For some reason it took a couple of tries to get that one through. Maybe attachement size was too big but it made it to the nabble list:

http://vtk.1045678.n5.nabble.com/vtkCutter-leaves-quot-gaps-quot-tt5724617.html

 

David,

Right, it feels like a bug in polyhedron cells.

My data was pretty simple, a block with poly cells a with varying thickness and width.

Definitely no holes. I probably can’t send it along but

note there was just recently a post (probably minutes before my “BUMP” made it through) about a very similar issue:

http://vtk.1045678.n5.nabble.com/Bug-in-slice-and-clip-for-mesh-containing-VTK-POLYHEDRON-cells-tt5724879.html

It also has a problematic model attached.

 

Gerrick

 

 

From: David Gobbi [mailto:[hidden email]]
Sent: Friday, December 06, 2013 12:42 PM
To: Gerrick Bivins
Cc: Bill Lorensen; [hidden email]
Subject: Re: [vtkusers] vtkCutter leaves "gaps"

 

Hi Gerrick,

 

The cutter algorithm is fairly straightforward, it just creates a new point along each edge that is intersected by the plane.  Then it uses its knowledge about the connectivity of the original cells to join the new points together to create new cells.

 

The only problem I've ever seen with vtkCutter is the fact that its locator is limited by numerical precision: it might think two cells share an edge when in fact the edges are just very, very close to each other.  But the result of this is that gaps are closed, not created.

 

In response to the question about whether I've ever seen vtkCutter create gaps where no gaps exist in the original data, I'd have to say no.  That's not to say that it could never happen.  The vtkCutter delegates the "cutting" to the Contour methods of the various cell classes, so it is possible that your data uses a cell type with a buggy Contour implementation.  If that is the case, it would be good to know the details of your data so that someone can investigate, but my first suspicion is that the gaps are present in your original data.

 

  David

 

On Fri, Dec 6, 2013 at 11:13 AM, Bill Lorensen <[hidden email]> wrote:

I do not see the attachment/

 

On Fri, Dec 6, 2013 at 12:50 PM, Gerrick Bivins <[hidden email]> wrote:

I realized I sent this at a time when most people were probably offline.

Just a “BUMP” in case this got missed.

Anyone have any ideas here?

Gerrick

From: [hidden email] [mailto:[hidden email]] On Behalf Of Gerrick Bivins
Sent: Monday, November 25, 2013 8:33 AM
To: '[hidden email]'
Subject: [vtkusers] vtkCutter leaves "gaps"

 

Hi All,

I’ve run into a strange problem where with some of my datasets, vtkCutter is leaving “gaps” in the output polydata.

For example, if I use a plane as the implicit function the attached image shows the result.

Anyone seen this kind of  behavior before?

Is there some setting on the vtkCutter that is perhaps causing this?

 

Gerrick

 

 

 

DecisionSpace® 5000.8.3 Now Available

 


This e-mail, including any attached files, may contain confidential and privileged information for the sole use of the intended recipient. Any review, use, distribution, or disclosure by others is strictly prohibited. If you are not the intended recipient (or authorized to receive information for the intended recipient), please contact the sender by reply e-mail and delete all copies of this message.

 

 



_______________________________________________
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Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html

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Re: vtkCutter leaves "gaps"

Jeff Lee-2
the contour algorithm for polyhedra is pretty complicated and you are probably hitting some edge case, if you can donate the test case and file a bug then it will be easier to see where things are going wrong.  tetrahedralization of polys might work on very simple hex geometry but it wont work on nonconvex cells.
Jeff


On Mon, Dec 9, 2013 at 11:55 AM, David Gobbi <[hidden email]> wrote:
A "Tesselator" filter, I think?


On Mon, Dec 9, 2013 at 9:43 AM, Gerrick Bivins <[hidden email]> wrote:

Ok. I tried to  “Tetrahedralize” the dataset before using the cutter, and it produced

a “gapless” slice in paraview.

It loses the structure of the cells (everything is triangles obviously) but at least it doesn’t drop elements.

 

What filter does “Tetrahedralize” map to in VTK?

 

Gerrick

From: David Gobbi [mailto:[hidden email]]
Sent: Friday, December 06, 2013 2:01 PM


To: Gerrick Bivins
Cc: Bill Lorensen; [hidden email]
Subject: Re: [vtkusers] vtkCutter leaves "gaps"

 

Hi Gerrick,

 

If it's polyhedral cells, then yes, a bug is a definite possibility.  Gathering info from other poly users is the right way to go.  Sorry that I can't be of more help, but I haven't used poly cells myself.

 

  David

 

On Fri, Dec 6, 2013 at 12:47 PM, Gerrick Bivins <[hidden email]> wrote:

Bill,

For some reason it took a couple of tries to get that one through. Maybe attachement size was too big but it made it to the nabble list:

http://vtk.1045678.n5.nabble.com/vtkCutter-leaves-quot-gaps-quot-tt5724617.html

 

David,

Right, it feels like a bug in polyhedron cells.

My data was pretty simple, a block with poly cells a with varying thickness and width.

Definitely no holes. I probably can’t send it along but

note there was just recently a post (probably minutes before my “BUMP” made it through) about a very similar issue:

http://vtk.1045678.n5.nabble.com/Bug-in-slice-and-clip-for-mesh-containing-VTK-POLYHEDRON-cells-tt5724879.html

It also has a problematic model attached.

 

Gerrick

 

 

From: David Gobbi [mailto:[hidden email]]
Sent: Friday, December 06, 2013 12:42 PM
To: Gerrick Bivins
Cc: Bill Lorensen; [hidden email]
Subject: Re: [vtkusers] vtkCutter leaves "gaps"

 

Hi Gerrick,

 

The cutter algorithm is fairly straightforward, it just creates a new point along each edge that is intersected by the plane.  Then it uses its knowledge about the connectivity of the original cells to join the new points together to create new cells.

 

The only problem I've ever seen with vtkCutter is the fact that its locator is limited by numerical precision: it might think two cells share an edge when in fact the edges are just very, very close to each other.  But the result of this is that gaps are closed, not created.

 

In response to the question about whether I've ever seen vtkCutter create gaps where no gaps exist in the original data, I'd have to say no.  That's not to say that it could never happen.  The vtkCutter delegates the "cutting" to the Contour methods of the various cell classes, so it is possible that your data uses a cell type with a buggy Contour implementation.  If that is the case, it would be good to know the details of your data so that someone can investigate, but my first suspicion is that the gaps are present in your original data.

 

  David

 

On Fri, Dec 6, 2013 at 11:13 AM, Bill Lorensen <[hidden email]> wrote:

I do not see the attachment/

 

On Fri, Dec 6, 2013 at 12:50 PM, Gerrick Bivins <[hidden email]> wrote:

I realized I sent this at a time when most people were probably offline.

Just a “BUMP” in case this got missed.

Anyone have any ideas here?

Gerrick

From: [hidden email] [mailto:[hidden email]] On Behalf Of Gerrick Bivins
Sent: Monday, November 25, 2013 8:33 AM
To: '[hidden email]'
Subject: [vtkusers] vtkCutter leaves "gaps"

 

Hi All,

I’ve run into a strange problem where with some of my datasets, vtkCutter is leaving “gaps” in the output polydata.

For example, if I use a plane as the implicit function the attached image shows the result.

Anyone seen this kind of  behavior before?

Is there some setting on the vtkCutter that is perhaps causing this?

 

Gerrick

 

 

 

DecisionSpace® 5000.8.3 Now Available

 


This e-mail, including any attached files, may contain confidential and privileged information for the sole use of the intended recipient. Any review, use, distribution, or disclosure by others is strictly prohibited. If you are not the intended recipient (or authorized to receive information for the intended recipient), please contact the sender by reply e-mail and delete all copies of this message.

 

 



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Re: vtkCutter leaves "gaps"

Gerrick Bivins

Tis the season of giving, Bug filed:

http://vtk.org/Bug/view.php?id=14485

 

There are a couple of other issues I’ve run into with polyhedron cells but looks like they are already logged:

http://vtk.org/Bug/view.php?id=14485

http://vtk.org/Bug/view.php?id=13944

http://vtk.org/Bug/view.php?id=14237

 

 

Gerrick

From: Jeff Lee [mailto:[hidden email]]
Sent: Monday, December 09, 2013 4:45 PM
To: David Gobbi
Cc: Gerrick Bivins; [hidden email]
Subject: Re: [vtkusers] vtkCutter leaves "gaps"

 

the contour algorithm for polyhedra is pretty complicated and you are probably hitting some edge case, if you can donate the test case and file a bug then it will be easier to see where things are going wrong.  tetrahedralization of polys might work on very simple hex geometry but it wont work on nonconvex cells.

Jeff

 

On Mon, Dec 9, 2013 at 11:55 AM, David Gobbi <[hidden email]> wrote:

A "Tesselator" filter, I think?

 

On Mon, Dec 9, 2013 at 9:43 AM, Gerrick Bivins <[hidden email]> wrote:

Ok. I tried to  “Tetrahedralize” the dataset before using the cutter, and it produced

a “gapless” slice in paraview.

It loses the structure of the cells (everything is triangles obviously) but at least it doesn’t drop elements.

 

What filter does “Tetrahedralize” map to in VTK?

 

Gerrick

From: David Gobbi [mailto:[hidden email]]
Sent: Friday, December 06, 2013 2:01 PM


To: Gerrick Bivins
Cc: Bill Lorensen; [hidden email]
Subject: Re: [vtkusers] vtkCutter leaves "gaps"

 

Hi Gerrick,

 

If it's polyhedral cells, then yes, a bug is a definite possibility.  Gathering info from other poly users is the right way to go.  Sorry that I can't be of more help, but I haven't used poly cells myself.

 

  David

 

On Fri, Dec 6, 2013 at 12:47 PM, Gerrick Bivins <[hidden email]> wrote:

Bill,

For some reason it took a couple of tries to get that one through. Maybe attachement size was too big but it made it to the nabble list:

http://vtk.1045678.n5.nabble.com/vtkCutter-leaves-quot-gaps-quot-tt5724617.html

 

David,

Right, it feels like a bug in polyhedron cells.

My data was pretty simple, a block with poly cells a with varying thickness and width.

Definitely no holes. I probably can’t send it along but

note there was just recently a post (probably minutes before my “BUMP” made it through) about a very similar issue:

http://vtk.1045678.n5.nabble.com/Bug-in-slice-and-clip-for-mesh-containing-VTK-POLYHEDRON-cells-tt5724879.html

It also has a problematic model attached.

 

Gerrick

 

 

From: David Gobbi [mailto:[hidden email]]
Sent: Friday, December 06, 2013 12:42 PM
To: Gerrick Bivins
Cc: Bill Lorensen; [hidden email]
Subject: Re: [vtkusers] vtkCutter leaves "gaps"

 

Hi Gerrick,

 

The cutter algorithm is fairly straightforward, it just creates a new point along each edge that is intersected by the plane.  Then it uses its knowledge about the connectivity of the original cells to join the new points together to create new cells.

 

The only problem I've ever seen with vtkCutter is the fact that its locator is limited by numerical precision: it might think two cells share an edge when in fact the edges are just very, very close to each other.  But the result of this is that gaps are closed, not created.

 

In response to the question about whether I've ever seen vtkCutter create gaps where no gaps exist in the original data, I'd have to say no.  That's not to say that it could never happen.  The vtkCutter delegates the "cutting" to the Contour methods of the various cell classes, so it is possible that your data uses a cell type with a buggy Contour implementation.  If that is the case, it would be good to know the details of your data so that someone can investigate, but my first suspicion is that the gaps are present in your original data.

 

  David

 

On Fri, Dec 6, 2013 at 11:13 AM, Bill Lorensen <[hidden email]> wrote:

I do not see the attachment/

 

On Fri, Dec 6, 2013 at 12:50 PM, Gerrick Bivins <[hidden email]> wrote:

I realized I sent this at a time when most people were probably offline.

Just a “BUMP” in case this got missed.

Anyone have any ideas here?

Gerrick

From: [hidden email] [mailto:[hidden email]] On Behalf Of Gerrick Bivins
Sent: Monday, November 25, 2013 8:33 AM
To: '[hidden email]'
Subject: [vtkusers] vtkCutter leaves "gaps"

 

Hi All,

I’ve run into a strange problem where with some of my datasets, vtkCutter is leaving “gaps” in the output polydata.

For example, if I use a plane as the implicit function the attached image shows the result.

Anyone seen this kind of  behavior before?

Is there some setting on the vtkCutter that is perhaps causing this?

 

Gerrick

 

 

 

DecisionSpace® 5000.8.3 Now Available

 


This e-mail, including any attached files, may contain confidential and privileged information for the sole use of the intended recipient. Any review, use, distribution, or disclosure by others is strictly prohibited. If you are not the intended recipient (or authorized to receive information for the intended recipient), please contact the sender by reply e-mail and delete all copies of this message.

 

 

 


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Powered by www.kitware.com

Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html

Please keep messages on-topic and check the VTK FAQ at: http://www.vtk.org/Wiki/VTK_FAQ

Follow this link to subscribe/unsubscribe:
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Re: vtkCutter leaves "gaps"

Gerrick Bivins

Has this bug had a chance to be “triaged” yet ?

http://vtk.org/Bug/view.php?id=14485

Also as a side note, I and noticed I can’t edit any of the info on it (severity and category for instance) even though I “reported” it.

 

Gerrick

 

 

From: [hidden email] [mailto:[hidden email]] On Behalf Of Gerrick Bivins
Sent: Friday, December 20, 2013 1:59 PM
To: Jeff Lee; David Gobbi
Cc: [hidden email]
Subject: Re: [vtkusers] vtkCutter leaves "gaps"

 

Tis the season of giving, Bug filed:

http://vtk.org/Bug/view.php?id=14485

 

There are a couple of other issues I’ve run into with polyhedron cells but looks like they are already logged:

http://vtk.org/Bug/view.php?id=14485

http://vtk.org/Bug/view.php?id=13944

http://vtk.org/Bug/view.php?id=14237

 

 

Gerrick

From: Jeff Lee [[hidden email]]
Sent: Monday, December 09, 2013 4:45 PM
To: David Gobbi
Cc: Gerrick Bivins; [hidden email]
Subject: Re: [vtkusers] vtkCutter leaves "gaps"

 

the contour algorithm for polyhedra is pretty complicated and you are probably hitting some edge case, if you can donate the test case and file a bug then it will be easier to see where things are going wrong.  tetrahedralization of polys might work on very simple hex geometry but it wont work on nonconvex cells.

Jeff

 

On Mon, Dec 9, 2013 at 11:55 AM, David Gobbi <[hidden email]> wrote:

A "Tesselator" filter, I think?

 

On Mon, Dec 9, 2013 at 9:43 AM, Gerrick Bivins <[hidden email]> wrote:

Ok. I tried to  “Tetrahedralize” the dataset before using the cutter, and it produced

a “gapless” slice in paraview.

It loses the structure of the cells (everything is triangles obviously) but at least it doesn’t drop elements.

 

What filter does “Tetrahedralize” map to in VTK?

 

Gerrick

From: David Gobbi [mailto:[hidden email]]
Sent: Friday, December 06, 2013 2:01 PM


To: Gerrick Bivins
Cc: Bill Lorensen; [hidden email]
Subject: Re: [vtkusers] vtkCutter leaves "gaps"

 

Hi Gerrick,

 

If it's polyhedral cells, then yes, a bug is a definite possibility.  Gathering info from other poly users is the right way to go.  Sorry that I can't be of more help, but I haven't used poly cells myself.

 

  David

 

On Fri, Dec 6, 2013 at 12:47 PM, Gerrick Bivins <[hidden email]> wrote:

Bill,

For some reason it took a couple of tries to get that one through. Maybe attachement size was too big but it made it to the nabble list:

http://vtk.1045678.n5.nabble.com/vtkCutter-leaves-quot-gaps-quot-tt5724617.html

 

David,

Right, it feels like a bug in polyhedron cells.

My data was pretty simple, a block with poly cells a with varying thickness and width.

Definitely no holes. I probably can’t send it along but

note there was just recently a post (probably minutes before my “BUMP” made it through) about a very similar issue:

http://vtk.1045678.n5.nabble.com/Bug-in-slice-and-clip-for-mesh-containing-VTK-POLYHEDRON-cells-tt5724879.html

It also has a problematic model attached.

 

Gerrick

 

 

From: David Gobbi [mailto:[hidden email]]
Sent: Friday, December 06, 2013 12:42 PM
To: Gerrick Bivins
Cc: Bill Lorensen; [hidden email]
Subject: Re: [vtkusers] vtkCutter leaves "gaps"

 

Hi Gerrick,

 

The cutter algorithm is fairly straightforward, it just creates a new point along each edge that is intersected by the plane.  Then it uses its knowledge about the connectivity of the original cells to join the new points together to create new cells.

 

The only problem I've ever seen with vtkCutter is the fact that its locator is limited by numerical precision: it might think two cells share an edge when in fact the edges are just very, very close to each other.  But the result of this is that gaps are closed, not created.

 

In response to the question about whether I've ever seen vtkCutter create gaps where no gaps exist in the original data, I'd have to say no.  That's not to say that it could never happen.  The vtkCutter delegates the "cutting" to the Contour methods of the various cell classes, so it is possible that your data uses a cell type with a buggy Contour implementation.  If that is the case, it would be good to know the details of your data so that someone can investigate, but my first suspicion is that the gaps are present in your original data.

 

  David

 

On Fri, Dec 6, 2013 at 11:13 AM, Bill Lorensen <[hidden email]> wrote:

I do not see the attachment/

 

On Fri, Dec 6, 2013 at 12:50 PM, Gerrick Bivins <[hidden email]> wrote:

I realized I sent this at a time when most people were probably offline.

Just a “BUMP” in case this got missed.

Anyone have any ideas here?

Gerrick

From: [hidden email] [mailto:[hidden email]] On Behalf Of Gerrick Bivins
Sent: Monday, November 25, 2013 8:33 AM
To: '[hidden email]'
Subject: [vtkusers] vtkCutter leaves "gaps"

 

Hi All,

I’ve run into a strange problem where with some of my datasets, vtkCutter is leaving “gaps” in the output polydata.

For example, if I use a plane as the implicit function the attached image shows the result.

Anyone seen this kind of  behavior before?

Is there some setting on the vtkCutter that is perhaps causing this?

 

Gerrick

 

 

 

DecisionSpace® 5000.8.3 Now Available

 


This e-mail, including any attached files, may contain confidential and privileged information for the sole use of the intended recipient. Any review, use, distribution, or disclosure by others is strictly prohibited. If you are not the intended recipient (or authorized to receive information for the intended recipient), please contact the sender by reply e-mail and delete all copies of this message.

 

 

 


_______________________________________________
Powered by www.kitware.com

Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html

Please keep messages on-topic and check the VTK FAQ at: http://www.vtk.org/Wiki/VTK_FAQ

Follow this link to subscribe/unsubscribe:
http://www.vtk.org/mailman/listinfo/vtkusers

 


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Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html

Please keep messages on-topic and check the VTK FAQ at: http://www.vtk.org/Wiki/VTK_FAQ

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