Preform Auto Support Generation: why so much resin?

I’m just curious if anyone knows the physics behind Preform’s decision to build so much infrastructure into the supports, regardless of the number of touch-points.

For example - this is an auto-generated support for a ball and socket structure:

Note all the extra strength in the base (this part is about 2 CM tall)

vs this manual approach with the same touch points…

The latter definitely saves a bit of resin, prints faster, and would seem to generate less bubbling/heat/deformities when using black resin.

Both are aligned parallel to the hinge-side of the tank. So perhaps that is the thing: if they were perpendicular to the hinge, we’d need more intra-supports like the first picture?

Just wondering as I’m starting to delete these intra-supports a bit more and have not see failures yet. Perhaps this could be an option when doing autogeneration to turn that off or make it less aggressive?



PS these are both the exact same auto-gen situation - I just manually deleted the ‘intra-supports’

Most of the work I do in PreForm is removing all the arches. Without them the print uses much less resin and is also easier to remove from the base. I haven’t noticed any problems with my prints. I agree that PreForm needs a “toggle arches” or “remove all arches” feature, perhaps we should move this thread to feature requests.

The arches make the entire group of support as a system to resist moments and lateral forces during peel. I am not an engineer but this what I can think.

Thanks Cesar. I have had some success when removing them, but I’ll admit that is in situations where the part is very close and parallel to the hinge… so that the stress from the peel is probably not putting stress laterally across that range of supports. I could not say it would work so well if the length of that part was perpendicular to the hinge side. I’ll continue to test sparingly. (These are also very small parts so that may help as well.

Testing is expensive. I am the point where just need parts to just come out and despite “lessons learned” and using an FDM printer to make similar mechanical parts seem quicker and produces in my eyes a better product - for such application…