Bug in support generation is wrecking my prints

Hi @Formlabs1 ,
I’ve mentioned this several times in the past, both here and in the application feedback panel, but this is a bug that really needs to be addressed ASAP, either by allowing the user to drag the support-post bases around after generation, or fix the generator to actually do the right thing on it’s own.

In the image, you can see a small part (about 3cm tall, and 2mm thick). Printing it vertically, like many of my parts, produces the best print, except when the support generation algorithm works against me, and literally destroys my parts. I will not accept the ‘print it at an angle’ excuse as a solution. That does not fix the problem, it merely causes other, different problems.

It’s a bit hard to see on the clear part, so I’ve drawn black lines on the photo showing where the support sides are completely fused to the surface of the part. Supports are also fused on the backside as well. The tips of the supports are in the right location, and these are all I obviously want to touch the part.

I’ve increased the hieght of the supports on some other parts of a different geometry, and this can accidentally minimize this phenomenon somewhat, but that adds considerably to the print time for no good reason, and is not a fix - it’s an unintentional side-effect.

There is no way to remove the supports on the part in the image without destroying it. Which sucks, because otherwise it’s perfectly fine.

Obviously, the algorithm must make a complete pass after generation to verify there are no collisions of support posts to part. Either there is a parameter I can adjust (e.g. minimum distance of post to part) pre-generation, or I need to be able to drag the post base around (within some radius) post-generation. Dragging the post base so I can see it’s position in real-time would be the preferred method.

Please. Can you try to fix this problem? This is really effing up my ability to get things done.



I’ve also noticed this problem with supports welding to the actual print, although in the software everything looks fine.

right - it seems like it’s missing the part by a very tiny amount - but it aint!

I think you can get away with deleting the supports that are causing you issues. Rotating it clockwise a little bit would help it print (without supports) a bit cleaner too.

Are you using Preform 1.9.1? If yes, can you send us the file so we can take a look?


Hi @Jory
Yes, running latest code. See .form file attached. Hmm, wait, no. It can’t be uploaded, as it’s 13MB and 7MB is the maximum file size one may upload for some odd reason… Does anyone even have a .form file less than 7MB?
Here’s an image instead, and I’ll email support the .form file.

Another thing to notice in the generated structure is the weird doubling of struts where it’s obvious a single entity would suffice.

@ChristopherBarr, Have you tried printing the part with deleting the 3 supports on this side as well as deleting the ones from the other side that are welding themselves to the part? Looking at the part, it should be ok if it is placed near the hinge.

@Jory, It would be nice to be able to edit the base support locations like we can edit the attachment points to the model. This would give us the ability to preserve model faces in cases like this.

Hi @DavidRosenfeld,

Yes, I’ve tried that. I get distortion or dropped layers. This part is not actually round, it’s slightly eliptical. Even though I have dialed in my printer as best I can, to ensure symmetry, I need to keep it straight up to keep it as precise as possible. Notice the lower opening (closest to build platform); the center of the upper surface needs to print before the ousides. With no support this area would not print right. The other supports help stabilize and minimize distortion.

The point I’m trying to make with this post is exactly what you are re-stating here:

This part is not the only part I’m doing that is negatively affected by this issue. In fact, for other parts it’s even more of a problem. It’s simply that I can show this part to the World without compromising my design.

Simply put, what I am trying to get across is at no time should support sides contact the object being printed.
If that proves to be too difficult to code for every possible permutation of object and support need, that’s fine, just give me the ability to manually modify the support bases.


Now I see. I didn’t notice that part hanging below. Oops. Would it be possible to add a thin surface or support yourself and cut it away after the part is printed? I know you should not have to do this but until FL adds the feature, I do not see how else to print the part successfully.

Have you tried printing mold halves and casting the part? Since the part would have to get sanded / finished removing the supports from the edge, You could add the pour hole on the edge and cut away any flashing, air vents, fill holes. Again, not what you should have to do but maybe as a temporary work around.

@Jory, This has been a pain for me on occasion as well. I know you can’t promise anything, but could this be added to the feature request list.

@Christopher - yes emailing over to support@formlabs.com is fine. We can take a look there.

@David - that’s a good thought! We are taking a look into why this is happening and the best way to resolve. Our software team is in full swing pushing improvements to Preform with each release.


I removed some supports, and added a few to force the algorithm to have to keep the supports sides away-ish from the surface (e.g. by putting a support point right where it was fusing). In this way I have printed the part in the file so I can use it. Was not perfect, and the support fusing issue is still huge problem, but I’m moving forward. I can’t say I need support (no pun intended) on this other than a code correction for hopefully, ideally, pretty please v1.9.2.

Thanks for all of your help/advice.


I have also had this fusion of supports to model. I now have to just keep replacing the support until it is at a fair distance.

Yeah, they’re telling me it’s not really a bug, I’m just using the tool wrong. Printing vertical is not something they ‘support’ apparently.

@ChristopherBarr, can you elaborate on you are just using the tool wrong?

I am not sure I would classify the issue as a bug myself, but what we have seen certainly needs to be addressed in a future update. There needs to be a way to edit the support bases for our needs. Not just live with what we get. With Jory saying they are looking into what is going on, I have to believe him. He has not lead me astray yet. We will just have to wait and see.

If FL had said that we have to use PreForm how they say per the guidelines, I would have never been able to print some of my parts.

The earrings are off my Form 1+. The coin is an old print off my old Form 1 that could have benefited from a few more edge supports and probably better orientation but overall the text is readable (not so much in the pictures) and the poor paint job didn’t help with the clarity.

Being able to triangulate edge supports to secure the coin from waving side to while keeping the faces free from supports would be great. One day.


Eh, I was just whining. I’ll get over it. :smile:

I know they’ll fix it. just a million other things to do too.

Have you tried creating supports in the free Autodesk MeshMixer? You can create the support structures where you think they should go and then export an STL of your work from there. Import that STL into PreForm and mount the bottom of the sports flat to the build platform. Just an alternative workflow. Good Luck!

I tried meshmixer a long time ago, but maybe it’s time to try it again. Thanks for the thoughts.


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