Minima Detection = Maxima Frustration

I can’t shake the feeling that this new “unsupported minima (UM)” business is only solving a problem that it created itself. Since this feature, literally EVERY file I work reports 10-50 UM. Statistically, that extrapolates to mean everything I’ve printed in the last two years must have been equally swarming with UM, just undetected. Yet I don’t recall two years of prints missing dozens of details, nor my PDMS full of adhered resin patches, nor resin gone sandy with free-range chunks. Neither do I recall it being a recurring forefront problem here on the forums in two years. So either UMs are hardly as serious as the big red blotches onscreen would imply, OR something else has also changed. The reason I say this is because I’ve seen areas on my new files needing such obvious support that I feel very sure older PreForm would have just put a support there and been done with it. I’d like to do some side-by-side tests with old and new Preform on a test file, if time ever permits. But based on my printing success rate and history, I have a gut feeling that Preform now takes some of it’s previously-automatic support-placement and dumps the responsibility into the laps of the users to finish manually. Or in other words, to give this UM feature more credibility as a great new thing, the procedure it augments (support placement) has been “dumbed down” somehow. All I know is that after two years of mostly plug ‘n’ play printing, now I’m scared to send anything without many minutes of manual surgery.

And what only makes it better? On fixing the 29th UM out of 30, suddenly I’m not allowed to place the support point anywhere near where it’s needed to fix things. “Support point cannot be placed where indicated” or some such. What’s up with that? So now, no hope of turning that red barred circle into a check mark unless I reorient the whole figure one or two degrees and start all over… I’m finding it difficult to call this progress.

@Volguus Yeah part of me likes the feature and part of me hates it. I dont really trust it. It seems so random at times. Like RNG in a modern videogame. I also struggle with it randomly not allowing me to put a support in. Like there are areas it highlights that dont seem to need it then other areas that obviously need support but it deems fine.

I’ve ignored the warning every time I have gotten it and haven’t noticed any problems with the finished print. Perhaps our prints don’t need to be as precise as some. We are vinyl extruders and the nature of that beast is part science part art …So usually our prints are closer to our die print than the actual extrusion.

In many cases, unsupported minima that’s close to adjacent geometry will recover. It tends to be optimal to support any minima as even if they do recover, dimensional accuracy will take a small hit, and they could lead to stray cured resin in the tank. That said, I’m surprised by the 10-50UM volume you’re seeing. Do these all seem to be minima that are close enough to adjacent geometry that they recover, or do some of them seem to be false positives?

Our team has been focusing on updating the support generation algorithms to improve cleanup without sacrificing reliability. This might account for the differences in placement you’re seeing, and our intention isn’t to defer support placement to the user. I’ll get in touch with our team to make sure we haven’t made any negative changes to automatic support placement on minima.

I’ve run into the ‘can’t place support point’ error a few times, and it’s frustrating especially after adding a number of other custom points. There are same regions that can’t accommodate supports, and modifying orientation is the best option there.

Maybe a more realistic question to ask is: if the unsupported minima detector can pinpoint the need for a support, literally with a nice red bullseye, then why doesn’t it, like, y’know, just PUT ONE THERE? Or at least try to, so that the only unsupported minima left to report would be the ones that won’t allow a point placement, and you’ll know right away that the ONLY cure is to reorient? The “Printability” results may take a few more seconds to arrive, but in my experience that’s already a “take a break from the computer” moment anyway so it shouldn’t matter much. :wink:


A button next to the minima warning to “populate detected minima with supports” might be a good idea :wink:


I just upgraded to the latest version of preform, all my old .form files are now reporting “unsupported minina” although in most cases there are no red areas that I can see. The support points were all done manually since I can never trust the automatic support generator.

All the files print OK. It seems to be rather useless feature.

Let me clarify for Jhnywalter, In most cases Preform actually generates the supports. What I have to do manually is select the support points. In some special cases I build some of the supports into the 3D model.

Yea I’ve been ignoring the small errors in preform as it doesn’t seem to be working quite perfectly detecting issues.