1
$\begingroup$

I'm trying to use the knife tool. I click on the tool and it does appear.

But when I try to press LMB to cut, instead of the guidelines I am supposed to create appearing, the only thing that happens is that only the green square that marks the beginning appears, and it always appears at the source point of the object. (you can see in the gif I added that i'm trying to click and nothing happens)

In addition, from time to time it happens that the tool does respond to my clicks. (It should be noted that sometimes it reacts and sometimes not. In both cases it happens for no apparent reason) But even when the tool responds, it seems that for some reason it constantly insists on choosing the edges of the objects instead of creating edges the way I draw with the mouse.

I tried of course to check if it had anything to do with the edge selection mode, but no matter what mode I was in or what object I tried to perform the action on, All I could do was make this green square appear and nothing more.

I believe this is some definition that has changed in this specific project, because in every other project the knife works properly.

please help!!

enter image description here

$\endgroup$
9
  • $\begingroup$ What Blender version are you using? $\endgroup$
    – Emir
    May 31 at 15:40
  • $\begingroup$ you can share the blend file via blend-exchange.com so that it's easier for other to look into your issue. $\endgroup$
    – Nand 27
    May 31 at 17:07
  • $\begingroup$ for Emir: im using blender 2.91 $\endgroup$
    – JonasBH2
    May 31 at 17:11
  • $\begingroup$ for Nand 27: it doesn't let me upload files more then 30mb $\endgroup$
    – JonasBH2
    May 31 at 17:14
  • $\begingroup$ @JonasBH2 a standard procedure when reporting bugs or asking for help is reproducing the problem in as simple environment as possible. Creating a new project and reproducing the problem is sometimes hard, but removing half of the objects, checking if the problem remains and repeating that until there's a minimum number of objects still reproducing the issue, not only makes it easier to share the file, but also to find the problem. $\endgroup$ May 31 at 17:45
1
$\begingroup$

This issue occurs when you have overlapping geometry like double faces. try selecting all in vertex mode and hit m> merge by distance. this might be the solution for your issue!

$\endgroup$
5
  • $\begingroup$ ok! I can see the overlapped face in you screen. You can spot this when a face looks weird (something like weird shining). You can see it in the first selected face when you rotate the screen in the clip you shared. $\endgroup$
    – Nand 27
    May 31 at 16:46
  • $\begingroup$ I assume when u siad to "select all" you meant that I would select an object, then select all of its vertexes in edit mode with vertexes selection mode. i tried. nothing changed. Besides, the solution you suggested sounded more appropriate to me if the problem was with a particular object. In my case, the knife tool behaves this way about all the objects in the project, including new objects I create $\endgroup$
    – JonasBH2
    May 31 at 16:53
  • $\begingroup$ by the way, about what u said that u thought it was overlapped face, it was a seleted face $\endgroup$
    – JonasBH2
    May 31 at 17:00
  • $\begingroup$ sorry! it looked like a overlapped face, maybe due to the compression. if you don't find the solution it's best to copy all the objects to a new blend file. $\endgroup$
    – Nand 27
    May 31 at 17:03
  • $\begingroup$ It indeed looks like z-fighting when it moves, but looking on a paused frame reveals it's GIF dithering, not z-fighting: i.imgur.com/xB8XswE.png $\endgroup$ May 31 at 17:52

Not the answer you're looking for? Browse other questions tagged or ask your own question.