Support generation is hit or miss -- mostly miss

[siemslikelynn]

I don't think I fully understad S3D's support generation. How did it determine the most overhang part on this model didn't require supports... and the other supports all over it are just as spotty, seeming to choose when and if it bothers to put supports on a model at all.

I had to spend 45 minutes carefully placing my own supports which is way too much work when there are other slicers out there doing it perfectly the first time. Prusa had no issues supporting this model beautifully, but S3D has the superior quality and tolerances. With so many slicers out there making perfect supports, some of them open-source, I'm not sure I understand how S3D is continuing to miss the mark on this.

[S3D-Jason]

It might help to lower the size of your support pillars. They look a little large for that ledge. For example, instead of using 4mm pillars, try 1-2mm in size.

[siemslikelynn]

It might help to lower the size of your support pillars. They look a little large for that ledge. For example, instead of using 4mm pillars, try 1-2mm in size.

I tried that, it was bad for all possible options, I tried everything from 1mm to 4mm and every single time it missed large patches of overhangs seemingly for no reason.

[Al1deR]

Hello,
I found the same problem on many files

[siemslikelynn]

Hello,
I found the same problem on many files

For sure, it's not just one file, it's lots of them. The support generation is just garbage unless it is extremely straight forward overhangs with no thinking required by the program. Complexity is beyond it, and that makes me sad.

[gearsawe]

I total agree how it calculates if things need support. Most of the time it misses on very complex models and I miss what it misses very frustrating. if you have something with an edge of 0.75mm it probably will not get any support even though it should. Have found 4mm to never be close to adequate. Truthfully the pillar should be anything larger than half a bead width.

[billyd]

The problem is that S3D takes a short cut by creating an invisible grid on the bed. And supports are only placed on those grid points. So one approach is to move the model around slightly and see if you can get a better auto create support result and then edit from there. I agree they shouldn't take this approach and need to change it.

[siemslikelynn]

The problem is that S3D takes a short cut by creating an invisible grid on the bed. And supports are only placed on those grid points. So one approach is to move the model around slightly and see if you can get a better auto create support result and then edit from there. I agree they shouldn't take this approach and need to change it.

This is very interesting, thanks for the tip, I'll give it a try.

[gearsawe]

something to try a little bug to work to your advantage.
scale your design up. 400%. set pillars to 1mm. if you have room on your build plate.
generate the support. scale down by to 100% this effectively makes your support pillars 0.25mm. When you scale the supports also scale. Side note: another "bug" the scale might show 100% if the scale tool is closed and may not show 400% so may need to set to 25% if this happens. Been trying this on things with small over hang and it seem to actually work. Now if they would just let us set the grid smaller would be a more effective result. HINT!

Would like to hear if this work for your case

[kyleamorgan]

I would agree on the mostly miss part. I'm unable to add manual support in some areas (can add all around but there are random places where v5 just won't let me add any sort of support).

I've also noticed that a lot of supports that I've manually added don't show up once the model is sliced. The software removes most of them. I did not catch until I had a failed print because of missing supports and was able to reproduce what happened. See attached screenshots. The ones removed weren't even manually added.