Unnecessary support structures in Cura

[Patronus 3]

             

Why would Cura generate support where clearly it isn't needed? In the first two pictures it's a bit hard to see but support starts against an almost vertical wall (the side of a large hole) where it's not necessary at all, in fact it can't even be printed there because it never touches the part so I have all these loose extrusions sitting all over my part as it tries to print it in mid air.

In the third picture it's quite evident that a tall support beam is generated for no reason at all. Again it's not even touching the part and only takes time & material to print.

Support horizontal expansion only makes these support structures a bit wider/narrower but doesn't take them away. Is there anything I can do to remove these unnecessary supports (other than manually)?

Edited February 3, 2019 by Patronus

[kmanstudios 1,120]

What are your overhang settings? That will greatly influence how much, and where, supports are added. And, then there is the support's horizontal expansion. This will greatly influence other aspects of the support structure.

 

As or the support not touching, I am going to venture that is a limitation of the graphical representation. I have seen that on my slices and not had an issue with contact in the actual print.

 

[Patronus 3]

My overhang is at 55 degrees and as I said the horizontal expansion has no effect on this, apart of course from making it thicker/narrower along with the rest of the support. These supports appear on what looks like a 10 degree overhang or even less.

As for the support not touching, it is not a just graphical representation, it does not touch the part in real life also. As I said in my original post, the fact that it tries to print the support in mid air creates lots of loose extrusions all over my part.

Edited February 3, 2019 by Patronus

[kmanstudios 1,120]

28 minutes ago, Patronus said:

and as I said the horizontal expansion has no effect on this

I was just mentioning this to reinforce the notion, no other reason.

 

28 minutes ago, Patronus said:

As for the support not touching, it is not a just graphical representation, it does not touch the part in real life also.

Then, this is of note for team ultimaker

 

29 minutes ago, Patronus said:

As I said in my original post, the fact that it tries to print the support in mid air creates lots of loose extrusions all over my part.

Wow...a bit snippy in that as I get that you said things, but just tried to offer a holistic approach as my experience dictates. It is rarely just one thing such as my experience with the 'non' touching thing. As for 'printing in mid air' I see the support going all the way to the base on the right hand image. Or, am I looking at the wrong image, because everything else looks like it is settled on some sort of edge.

 

Also, have you just tried the support blocker?

[ahoeben 2,016]

4 hours ago, Patronus said:

Why would Cura generate support where clearly it isn't needed?

 

Because of a bug. Cura is extending the support that is needed on the top of the model all the way down to the buildplate, disregarding the fact that it intersects with the model.  I've read that this has been "mostly fixed" (whatever that means) for Cura 4.0 (but not yet in Cura 4.0 beta 1).

 

Edit: support blockers will not fix this.

Edited February 3, 2019 by ahoeben

[kmanstudios 1,120]

2 minutes ago, ahoeben said:

Edit: support blockers will not fix this.

Well, phooey.

[ahoeben 2,016]

2 minutes ago, kmanstudios said:

Well, phooey.

 

Well, one could use support blockers to remove the support for the top hole. Arguably that probably prints ok without support.

[ahoeben 2,016]

For details on the bug. see https://github.com/Ultimaker/Cura/issues/5156

Turns out the fix may already be in Cura 4 beta 1

[Patronus 3]

@kmanstudios sorry I didn't mean to be snippy and appreciate your interest. It's only the support in pic 1 and 2 that hangs in mid air. The support in pic 3 prints fine.

@ahoeben sounds like the bug you refer to is causing this problem. If Ultimaker are working on a fix then I'll wait for it.

[kmanstudios 1,120]

10 minutes ago, Patronus said:

kmanstudios sorry I didn't mean to be snippy and appreciate your interest.

❤️

 

Yeah, I have  a hard time reading intent (even in real life), so I really appreciate that 🙂

 

@ahoeben strikes again 👍