Preform support long&thing


I nottice preform sometimes makes very long support without connections to other supports. I am under the impression that with the tough material this is the cause of some of my failures.

Unless i add some supports myself or randomly move supports i cant controll how long a support gets without support for the support:)

You may want to arrange the support points manually, the automatic method doesn’t always do a good job and you can likely get better results if you place them yourself.

Also orient by hand. I can’t see the back side of the model, but I doubt it has to be angled that high. Tilting it down closer to the build platform will reduce the length of any long supports that do get generated.

It was angled this way because it did not fit otherwise :wink:
Also at this angle i limited the supports on the surfaces where i did not want any.

I fully agree that i can put my own supports to limit this. But isn’t the goal of preform to limit any manual edits? To be as automatic as possible?

I like the preform support system as a starting point but I would not feel good about sending a job without me adding or editing the computer generated supports. I’m not sure my edits help or hurt but I feel better doing it .

PreForm’s computer-generated orientations and supports should be considered starting points. Depending on the complexity of the print, what PreForm comes up with might not need or benefit from additional “organic” optimization. In my experience, the further away components of the print are from the build plate, the more better off you are orienting and adding supports manually. When I know I’m going to likely want to place my own supports, I let PreForm build an initial “scaffold” at a lower-than-100% support density (I’ll use 75% typically) and then I go edit manually to reinforce areas I feel would benefit.

The objective (mine anyway) is always to print with the fewest supports possible, since supports mar the surface of the print and need post-print finishing. Which can be a real PITA when you’ve got 100s of contact points to sand down…

But that being said, I’d say that maybe 50% of what I print, I print using PreForm orientation and supports unmodified.

I do the same technique–though I almost always replace the generated supports. For orientation, I have a box that’s the size of the build volume in my 3D software and I plan out the orientation there. The only issue I have is that with large objects the supports/base will extend further out from the model so you might not have enough room when the supports are added in Preform.

Re: Box - yep, I do the same thing… Two “standard” objects, a Form1 print volume and a Form2 print volume (actually, 90% of the print volume, to allow for the base to be slightly larger as you point out, Zachary).

Not only does this help with planning orientation, it prevents embarrassing “too large” for the printer errors.

Doesn’t the “slope multiplier” affect the crossmember settings?

I’ve never actually convinced myself I understood what slope multiplier did.

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Slope multiplier should affect how many supports are attached to a surface based on the angle of the surface–for example, with FDM printing you need support on surfaces beyond a certain angle or the print will droop. With SLA that’s not really as much of a problem, but you still need supports on large surfaces for stability, and if a layer is significantly bigger than the previous layer then it will also need supports.
Other than that, SLA really only needs supports where an area is not supported by a previous layer. That’s due to how each layer is supported while it cures.

Yeah, no, that part I get. I’m just not sure how exactly the numerical value relates to the behavior you describe…

Maybe it’s just density on the sloped areas regardless of angle.

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