Knife Tool when faces are exactly aligned (zero screen-space-area), get cut diagonally #43816

New Issue

Matsuiko · 2015-02-26T00:38:59+01:00

Matsuiko commented

2015-02-26 00:38:59 +01:00

System Information
Windows 7 SP1
Gtx 770

Blender Version
Broken: : Started at 2.72 until now 2.73a
Worked: 2.71

Short description of error

When > Knife Tool > Cut through > it will create a tri on other planes that is not projected ex. orthographic view + top

Video ( please download for High quality Drop Box )

2.73a Version ( Heavy Plugin and Shortcut Keys )
https://www.dropbox.com/s/87l9rfgxtgxooxv/2.73_Modified.mp4?dl=1

2.73a Restore Factory ( Deleted >Appdata > Blender foundation )
restored.mp4

2.71
knife is working as intended
https://www.dropbox.com/s/mj7o15o6eifmbjo/2.71.mp4?dl=0

TEST.blend

Q> Hi i would like to ask if i should mind because it is normal function and a new feature of 2.72 and not a bug ?

**System Information** Windows 7 SP1 Gtx 770 **Blender Version** Broken: : Started at 2.72 until now 2.73a Worked: 2.71 **Short description of error** When > Knife Tool > Cut through > it will create a tri on other planes that is not projected ex. orthographic view + top Video ( please download for High quality Drop Box ) 2.73a Version ( Heavy Plugin and Shortcut Keys ) https://www.dropbox.com/s/87l9rfgxtgxooxv/2.73_Modified.mp4?dl=1 2.73a Restore Factory ( Deleted >Appdata > Blender foundation ) [restored.mp4](https://archive.blender.org/developer/F145895/restored.mp4) 2.71 knife is working as intended https://www.dropbox.com/s/mj7o15o6eifmbjo/2.71.mp4?dl=0 [TEST.blend](https://archive.blender.org/developer/F145896/TEST.blend) Q> Hi i would like to ask if i should mind because it is normal function and a new feature of 2.72 and not a bug ?

Matsuiko commented

2015-02-26 00:38:59 +01:00

Changed status to: 'Open'

Matsuiko commented

2015-02-26 00:38:59 +01:00

Added subscriber: @hirokamatsuiko

Matsuiko commented

2015-02-26 00:47:21 +01:00

This comment was removed by @hirokamatsuiko

*This comment was removed by @hirokamatsuiko*

Matsuiko commented

2015-02-26 06:41:13 +01:00

More info : http://blenderartists.org/forum/showthread.php?363895-Problem-with-Knife-Tool-Behavior-Bug-Or-Normal&p=2825076#post2825076

Julian Eisel commented

2015-02-26 19:34:45 +01:00

Added subscribers: @ideasman42, @JulianEisel

Julian Eisel commented

2015-02-26 19:34:45 +01:00

Can only recreate this in Orthographic view.
I personally don't see a bug in here, the triangles might come from a change in the algorithm so this may be exceptional. It also shouldn't be a big deal to clean this up as you can just select the edge and press X/Del -> "Dissolve Edges"

@ideasman42, do you agree?

Can only recreate this in Orthographic view. I personally don't see a bug in here, the triangles might come from a change in the algorithm so this may be exceptional. It also shouldn't be a big deal to clean this up as you can just select the edge and press X/Del -> "Dissolve Edges" @ideasman42, do you agree?

Matsuiko commented

2015-02-26 20:12:51 +01:00

In #43816#291841, @JulianEisel wrote:
Can only recreate this in Orthographic view.
I personally don't see a bug in here, the triangles might come from a change in the algorithm so this may be exceptional. It also shouldn't be a big deal to clean this up as you can just select the edge and press X/Del -> "Dissolve Edges"

@ideasman42, do you agree?

yes im aware of dissolve edges function but
what if the object becomes complex

ive started learning blender at 2.71 version

ive download blender from 2.71 to 2.73b tested them one by one and
creating tri's started version 2.72a till 2.73a

anyway thanks for answer i really dont now know which one is the stable and confuse why the function is sudden altered while the knife tool in 2.71 do the cutting more clean ( ex. dont need to worry the tri face created and use the function dissolve )

> In #43816#291841, @JulianEisel wrote: > Can only recreate this in Orthographic view. > I personally don't see a bug in here, the triangles might come from a change in the algorithm so this may be exceptional. It also shouldn't be a big deal to clean this up as you can just select the edge and press X/Del -> "Dissolve Edges" > > @ideasman42, do you agree? yes im aware of dissolve edges function but what if the object becomes complex ive started learning blender at 2.71 version ive download blender from 2.71 to 2.73b tested them one by one and creating tri's started version 2.72a till 2.73a anyway thanks for answer i really dont now know which one is the stable and confuse why the function is sudden altered while the knife tool in 2.71 do the cutting more clean ( ex. dont need to worry the tri face created and use the function dissolve )

Campbell Barton commented

2015-03-02 14:38:32 +01:00

From watching the video Im still not totally sure what the error is. (diagonal cut across a face when that face is aligned directly on the view axis?)

if you perform cuts side-on to the mesh this may cause odd cuts like this, while we could attempt to check for this case, its likely to backfire in other places (since there would need to be some threshold - as faces approach being aligned to the view.)

However I found some issues with the knife tool while checking this bug,

(#43862, fixed d2b6c6fd9b)

Could you check a recent build to see if that fix also fixes this bug?

From watching the video Im still not totally sure what the error is. (diagonal cut across a face when that face is aligned directly on the view axis?) if you perform cuts side-on to the mesh this may cause odd cuts like this, while we could attempt to check for this case, its likely to backfire in other places (since there would need to be some threshold - as faces approach being aligned to the view.) However I found some issues with the knife tool while checking this bug, (#43862, fixed d2b6c6fd9b) Could you check a recent build to see if that fix also fixes this bug?

Matsuiko commented

2015-03-03 10:29:24 +01:00

In #43816#292621, @ideasman42 wrote:
From watching the video Im still not totally sure what the error is. (diagonal cut across a face when that face is aligned directly on the view axis?)

if you perform cuts side-on to the mesh this may cause odd cuts like this, while we could attempt to check for this case, its likely to backfire in other places (since there would need to be some threshold - as faces approach being aligned to the view.)

However I found some issues with the knife tool while checking this bug,

(#43862, fixed d2b6c6fd9b)

Could you check a recent build to see if that fix also fixes this bug?

**recent build
Bool Tool Method : https://www.dropbox.com/s/26xzvctf20wddp6/latest.mp4?dl=0
Manual Method : https://www.dropbox.com/s/7axs68t047banpi/manual.mp4?dl=0

Not Fix and still same as 2.72a
**

Hi yes exactly the vertical slice is cutting even in other view

from 2.71 to 2.72 ( no tri is created no need to dissolve )
http://i.imgur.com/ponqsoO.gif

now 2.72a to 2.73a ( same method but vertical slice is created which forms tri and need to dissolve )

http://i.imgur.com/9YephYW.gif

dissolving the tri in this simple object is easy
but what if Object is more complicated. sometimes the tri's that is created is unnoticeable in view i need to use mesh lint

now if my method wrong using knife ( cut through ) for quickly adding force loop cut then my apologize

Summary :
2.71 - 2.72 ( the cut is clean and no need to worry dissolving )
2.72a and later ( creation of vertical cut or tri's in other view )

Question :
is the cut through right now where it creates tri will be permanent implementation and really meant to be?

is cut through on version 2.71 and 2.72 is not normal and which was fix in 2.72a?

ive started version 2.71 and the sudden change of knife cut through behavior on 2.72a and later added confusion to me

thank you for answers and sorry for bad english i hope you understand

> In #43816#292621, @ideasman42 wrote: > From watching the video Im still not totally sure what the error is. (diagonal cut across a face when that face is aligned directly on the view axis?) > > if you perform cuts side-on to the mesh this may cause odd cuts like this, while we could attempt to check for this case, its likely to backfire in other places (since there would need to be some threshold - as faces approach being aligned to the view.) > > However I found some issues with the knife tool while checking this bug, > > (#43862, fixed d2b6c6fd9b) > > Could you check a recent build to see if that fix also fixes this bug? **recent build Bool Tool Method : https://www.dropbox.com/s/26xzvctf20wddp6/latest.mp4?dl=0 Manual Method : https://www.dropbox.com/s/7axs68t047banpi/manual.mp4?dl=0 Not Fix and still same as 2.72a ** ------------------------------------- Hi yes exactly the vertical slice is cutting even in other view from 2.71 to 2.72 ( no tri is created no need to dissolve ) http://i.imgur.com/ponqsoO.gif now 2.72a to 2.73a ( same method but vertical slice is created which forms tri and need to dissolve ) http://i.imgur.com/9YephYW.gif dissolving the tri in this simple object is easy but what if Object is more complicated. sometimes the tri's that is created is unnoticeable in view i need to use mesh lint now if my method wrong using knife ( cut through ) for quickly adding force loop cut then my apologize Summary : 2.71 - 2.72 ( the cut is clean and no need to worry dissolving ) 2.72a and later ( creation of vertical cut or tri's in other view ) Question : is the cut through right now where it creates tri will be permanent implementation and really meant to be? is cut through on version 2.71 and 2.72 is not normal and which was fix in 2.72a? ive started version 2.71 and the sudden change of knife cut through behavior on 2.72a and later added confusion to me thank you for answers and sorry for bad english i hope you understand

Julian Eisel commented

2015-03-09 01:05:08 +01:00

I wouldn't consider this as a bug tbh. There were quite some changes/fixes in that area recently, which always brings the risk of breakage, this is just something you have to live with. We usually get more improvements than breakages though ;)

So @ideasman42, awaiting your decision

I wouldn't consider this as a bug tbh. There were quite some changes/fixes in that area recently, which always brings the risk of breakage, this is just something you have to live with. We usually get more improvements than breakages though ;) So @ideasman42, awaiting your decision

Campbell Barton commented

2015-03-09 02:57:29 +01:00

This is something we could support ... but looking into it and its not really simple.

I had the idea we could do a check: If all a faces vertices intersect a single cutting line, ignore that face But this doesn't work reliably enough since in the example given, 3 vertices of a quad are often intersecting - so its not resolving the problem.

Setting this as TODO, nice to support but its not well defined what happens when a knife cut is nearly exactly crossing the entire face.
If you don't want to cut the face you're dragging your mouse over - you can always hide the face too.

http://wiki.blender.org/index.php/Dev:2.5/Source/Development/Todo/Tools#Mesh_Editing

This is something we could support ... but looking into it and its not really simple. I had the idea we could do a check: *If all a faces vertices intersect a single cutting line, ignore that face* But this doesn't work reliably enough since in the example given, 3 vertices of a quad are often intersecting - so its not resolving the problem. Setting this as TODO, nice to support but its not well defined what happens when a knife cut is nearly exactly crossing the entire face. If you don't want to cut the face you're dragging your mouse over - you can always hide the face too. http://wiki.blender.org/index.php/Dev:2.5/Source/Development/Todo/Tools#Mesh_Editing

Campbell Barton changed title from ~~Knife Tool is acting Weird when using Cut Through~~ to Knife Tool when faces are exactly aligned (zero screen-space-area), get cut diagonally

2015-03-09 02:58:42 +01:00

Philipp Oeser removed the

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Knife Tool when faces are exactly aligned (zero screen-space-area), get cut diagonally #43816

Not Fix and still same as 2.72a **

Not Fix and still same as 2.72a
**