Unnecessary supports. How tho get rid of them?  

Re: Unnecessary supports. How tho get rid of them?

Use support blockers ... lol.

A blocker on the bed does nothing. The blocker must surround the area of the part you want blocked.

Imagine printing a human hand in free air - to block all supports for it, place a support blocker that surrounds the hand.

Re: Unnecessary supports. How tho get rid of them?

As said before: Support blockers did NOT help.
The support I don't want is on the bed and therefore the blocker I created is also on the bed. Or am I doing it wrong?

Re: Unnecessary supports. How tho get rid of them?

As said before, they do work, but must be applied properly. Post your stl (in a zip) and I'll try making it work.

Re: Unnecessary supports. How tho get rid of them?

Thank you for your reply! Attached are the files.

Re: Unnecessary supports. How tho get rid of them?

Your attached modifier is too small. Make it larger, so it envelopes the areas you want to protect and it will work. Again: modifiers need to cover the area entirely. There are limitations, sort of a "minimum size" needed, but those cases will be obvious when you run into them.

Here's how they work:

Re: Unnecessary supports. How tho get rid of them?

Support is only wanted in the holes.

Re: Unnecessary supports. How tho get rid of them?

This is what I am using and which is not working:

Re: Unnecessary supports. How tho get rid of them?

Okay - I think you are worrying about a cosmetic effect/artifact. There is only a support first layer. No other support is being built up.

Re: Unnecessary supports. How tho get rid of them?

Yes. No support under the chamfer is my goal.
I have also done a few more tests. The support blockers seem to work fine on layer 1+ but on the first layer I am getting these additional supports.

Re: Unnecessary supports. How tho get rid of them?

Yea, you call it "cosmetic". My problem is that these are sticking to my print because the first layer is much wider than shown in the preview (called elephant foot?). I have to remove it manually.
Is the shown behavior a bug in Slic3r?

Re: Unnecessary supports. How tho get rid of them?

Its the nature of supports to overbuild the first layer. A good thing really because they only have half the adhesion of a normal first layer.

I've found that you can limit supports fairly well, but there seems to be a range of control: you can't expect to be ultra precise with it, some resolution limits are in place. A 1cm block may only provide 8mm coverage in some cases, or 12mm coverage in others.

You can reduce the width of supports in print settings, or increase your layer 1 height so you get less elephant foot. On your part reducing the support width might be okay.

Honestly though, I'd just turn on bridge detection and go without supports. Those holes are well withing the printers capabilities of bridging well. Turn on bridging, and then is not getting good results, slow bridging print speed from 80% down to 40%. Some might suggest turning up bridges to 100%...

And you might try making your modifier a bit larger on the inside dimension so it intrudes into the holes a bit, reducing the size of the supports that are being made.

I have to run, I'll take a look later if you're still working on this.

Re: Unnecessary supports. How tho get rid of them?

Why do they only have half the adhesion of a normal first layer? I think this overbuild is senseless.

Re: Unnecessary supports. How tho get rid of them?

I have a bug request in for the half filled first layer. And other support issues, too.

Re: Unnecessary supports. How tho get rid of them?

Yes, it would be great if you could look at it again. In the mean time I will try to print it without supports.
This is a repeatedly popping up issue for me because I often design boxes like this and every time I run into this issue.

Re: Unnecessary supports. How tho get rid of them?

Perhaps changing XY separation to 0.8 or .9 mm will help. It moves that extraneous support well away from the part - you'll only need to remove it from the bed.

It also reduces the area supported, but still supports the central perimeter overhang. 1 mm fully eliminates the detritus, but leaves only the external perimeter supported, not ideal.

Re: Unnecessary supports. How tho get rid of them?

Thank you for your effort!
I have now simply created circular supports by my self which work really great. Printing without supports didn't work so nice for me.

RE: Unnecessary supports. How tho get rid of them?

ps: the images I posted were lost in the April forum "degrade" ... they were one-off clips all named "capture.jpg". When Prusa agents moved the posts they did not consider same-name files and over wrote images. Thus, a few repeated images placed out of context.

Sadly, it makes many of the pre-April'19 posts on the new forum much less useful than they could have been.

RE: Unnecessary supports. How tho get rid of them?

Hi Tim,

regarding the forum upgrade, the previous version was a total mess and it took us several weeks just to organize the database to some reasonable shape. I'm aware the transfer wasn't 100%, but I'm working on it with the devs day and night. Thanks for the feedback. We will look into this today.

We have a backup of all the content, so we should be able to recover it.

RE: Unnecessary supports. How tho get rid of them?

Jakub - I've written a lot of software over the years, and ended up retiring while I was product manager for a fairly large engineering software platform people are still trying to figure out 10 years later (and still using it, too 😲 ).  Transferring a database is probably one of the tougher tasks to take on, and not sure I've ever seen it work the first time.   So yes, I am fully aware of the effort you are putting into this.  But also a bit frustrated: One, at myself for my not-so-good habit of not uniquely naming each and every image got caught up in the chaos. Two, by such an obvious "requirement" missed during testing. 

If it can be repaired, that will be great news.   And thank you for taking the time to let us know you are working the issue.