The tree supports in my project are supposed to support two faces, A and B in the pic. I’ve flooded the faces purple in Bamboo Studio. When the supports are generated, they look as if they would indeed support A and B. But when I look closer, there is no interfaces filament generated for face B. The support structures near face B come close to the model but do not seem to touch it (circle in pic)?!
There are a lot of pictures without a lot of explanation for why each was provided.
But, I think I can determine your question.
Why is the face shown in the last picture highlighted with a circle not shown with any support that touches the face?
I imagine because the photos show it doesn’t require it.
The edge is built up from below with an angle more than capable of being built up by touching the layer below it. No overhanging layers are shown in the image, at least nothing in blue like the bottom surface.
because the photos show it doesn’t require it. The edge is built up from below with an angle more than capable
Just because an angle allows printing without supports does not mean that supports are not necessary. Those supports at the edge have to carry a lot of weight before the supported part and the main part join late in the print. I need as much stabilization as possible at that edge (labeled “supports planned”) because I cannot place supports anywhere else. The label “this surface must be clean” indicates a surface where I should place supports but cannot afford blemishes. Without good stabilization at the edge, the printer will eventually tear the model apart. This happened multiple times today.
I guessed from the little you gave, and you are welcome to not like my attempt at help.
If you wish to enforce supports, use a support-enforced primitive object.
The overhang angle of the area circled in yellow is high enough it does not require supports. “A” needs support. “B” does not. There are other areas of your model with a similar angle as “B” that you are not supporting.
Even if there was an interface layer contacting the print at “B”, it wouldn’t make the print any better. Might even make it worse.
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There are other areas of your model with a similar angle as “B” that you are not supporting.
I’ve explained above that I don’t want to place supports in the area you’ve marked in yellow. This surface is very visible afterwards (top side; the print occurs upside-down). I can live with supports at the edge. I’m also fully aware that the printer can print the edge itself, consisting of faces A and B, without supports under B. I still want to attach supports at B because I neet to tie a large structure (circled) to the build plate well enough to survive the fast movements of the printer. Why doesn’t the slicer respect my manual choice? I think it is a bug.
You should paint some supports to the underside of that part on the right, to stabilize it properly before it’s joined to the part on the left. Adding supports to surface B doesn’t help stabilize that at all. That surface is under tension, not compression. For that surface to provide any stability, you would need to merge the supports with the print so that they were stuck together.
You need to put supports on this surface.
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It might seem overkill, but you can also design supports that are easy to snip away afterwards on spots where you can’t see the blemishes.
For work I had to have a twist shifter that needed to be strong, printing it at 45 degrees ensured this but made it almost impossible to print cleanly and fast with generated supports.
That’s why I designed a complete support interface that has enough bed surface against warping, physical contact points (very tiny bridges) and at the bottom it is fully connected with a saw line. It takes a couple minutes of cleanup but it prints flawlessly and fast every time:
Another thing I have done in connecting things at 45 is have a very tiny slit at the connection point so that the print will first lay parallel lines against each other (fusing both halves a bit together) before it starts bridging perpendicular and possibly knocking the print over:
These are not on how to fix the generated support issue that you were having. It might have to do with the threshold angle but I’m not yet comfortable enough in Studio. But in an unstable design like this I would really try to gain some more stability with snip off supports connecting at strategic points and try to force the slicer to bridge safer.
Thanks for the tips. The stairway supports idea made me realize that I need to rotate my model by 90 degrees on the plate to reduce the stress for the supports. I’m still thinking too much about vertical pull instead of the plate slinging (former SLA user). That seems to be sufficient for now, prints go through.
