Prusaslicer: Feature Request: Option to combine results of 'support from build plate only' and 'support enforcers only'

[Blargedy]

Version

2.1.0-alpha1

Operating system type + version

Windows 10 64-bit

3D printer brand / version + firmware version (if known)

Prusa i3 mk3s MMU2s

Behavior

I would like to be able to add a couple spots of support in addition to the supports generated when I select "from build plate". Currently I'd have to either do support everywhere with support blockers, or support enforcers everywhere I want supports, both of which are tedious for the two parts I want extra.

This is the part I want to print

These are the two spots supported with support enforcers

This unfortunately leaves the bottom unsupported

It is quite complex so I don't want to use 6 different support enforcers or 4-6 support blockers with support all selected.

I would need the support enforcer generated supports plus the build plate only supports

project file for reference

[Jebtrix]

I think using Everything with Overhang threshold and then use enforcers for things above the threshold is pretty much same result though, on this model at least.

As for your particular model just using Everywhere with 5% Overhang threshold adjustments seems to get what your looking for:

[Jebtrix]

Actually even Build Plate Only with low Overhang Threshold gets you same place. I guess to match exactly your posted pictures one support blocker would have to be used.

[Blargedy]

Either way, I can come up with other situations where your solution wouldn't solve it. A boolean OR operation on enforcers and build plate only would be quite useful to me I think.

[Jebtrix]

My workaround wasn't to refute the feature request, its a good one. I meant it as alternate way to deal with it with less work in the mean time for anybody that hits this thread. Plus once the feature drops you can still use it to save time and get the _build plate only_ to do more initial work.

[Blargedy]

That's fair, sorry for misunderstanding.

[JohnnyDeer]

Hi, in the latest version of PrusaSlicer is possible to combine support on build plate only with support enforcers.

[MikePfaff]

I support this feature request. I am trying to print 1:1 models of human brains (based on MRI scans) and "build plate only" generates most of the supports needed for a successful print, but in 2-3 places the auto-generated supports are not sufficient and the resulting print has ugly strings/blobs in these places.

Thus I would like to be able to add manual supports - in addition to the "build plate only" generated ones - in these specific places. Having to manually reproduce all the "build plate only" supports (either by using "everywhere - support blockers" or "support enforcers only") would be extremely tedious, as the 3D model is quite complex.

I might start playing around with the suggested "overhang threshold" workaround, but this seems rather time and filament intensive for each try (69h, 600g), although I might be able to make testing easier by just cutting up the model and printing the affected areas only.

A "build plate + support enforcers" option would probably solve all these issues for me. Maybe it could also make sense to think about a "build plate - support blockers" option for other peoples use cases?

@JohnnyDeer Is your post a question or a statement? In the release notes I didn't see any mention of this feature actually being added.

[MikePfaff]

After looking at src/libslic3r/SupportMaterial.cpp and trying in PrusaSlicer 2.1.1, i can confirm that this already works. Just add support enforcers to your model, select "Support on build plate only" and Slice.
I additionally verified that this works correctly when combining "Support on build plate only" with support blockers.

Thus suggesting that the wording in the GUI should be changed to say "Support on build plate" (without the "only"), so that it is clear to the user that support enforcers will still be added. The word "only" kind of implies to the user that nothing else gets added to the build plate supports.

Actually, this "only" word is what made me look for a fix / workaround - and discovering this open feature request - without even trying. I just assumed from the GUI that i could not add anything to "build plate only" supports.

@Blargedy: Can this issue be closed? (In that case i can then open a separate feature request for the GUI improvement)

[Blargedy]

@MikePfaff I am unable to replicate your results of getting both enforced and build plate supports. I am on PrusaSlicer 2.1.1. Attached is the 3mf file for a part I am currently printing, used to test your claim.
Cutlery_OrganiserSupportTest.zip
What the support enforcers do however do is add supports that are both from the build plate up AND intersecting with the support enforcer. I would like a feature that combines with logic OR the "Support on build plate only" and "For support enforcers only". In the attached file I would want the supports on the two sides as well as supports between the top edge and bottom wall.

[zalexzperez]

Definitely not working on PS 2.2.0 Alpha-4
You're forced to select supports everywhere and start adding many support blockers when only a single support enforcer + touching buildplate would've been perfect.

[JohnnyDeer]

Combination of "support on build plate only" with enforcers are not working ideally right now. We know about it and it is on our to do list.