cbarry
Posts: 11
Joined: Thu Apr 18, 2019 1:52 pm

support pattern tied to platform - not model

Wed May 27, 2020 5:56 pm

While the guys that coded this will likely call this oversimplification a 'feature' or 'optimization', it is clearly a shortcut that really cheeses out of doing the right thing.

Let me explain if anyone is unfamiliar with this issue (and by the way I did search for this issue, and came up empty handed).

You have a model with some overhangs, so you need to enable support. You obviously want to keep the support structure as minimal as possible for a variety of reasons, like not wasting material, or avoiding too many touch points to have to fix later, etc. The issue is that where on the bed the model sits will dictate how the supports get applied to the model, and not on the shape of the area to be supported. I know, it is a very strange optimization.

You would assume that the algo looked at the actual things to be supported, then would generate optimized supports exacly correct for that area. But you'd be wrong. Instead, the support structure's location on the bed is preordained by the percentage you set, and actually has nothing to do with the spot to be supported. What happens is an outline (and not a good one) is created for the area to be supported, and this outline is then used as a 'window' to allow the already calculated supports, based on the percentage you set, to poke through to hit the model. Now you know why the way the supports come out is almost arbitrary, often with areas needing support having nothing at all. Pure Unadulterated Cheddar.

So if you're supports do not hit the model in a reasonable way, shift you model on the bed slightly, and hit 'prepare to print' again, and you will observe the situation I describe above. I have to shift my model around very often to get supports that will work as expected. Of course I know I can laboriously insert individual support sticks, or let it add and then remove those I don't want. In the end, the underlying supports are aligned to the bed and not the model. The sticks are basically allowing you to define the window.

So S3D Developers, How about actually examining what needs to be supported, and generating the correct support pattern aligned for that particular area when they are needed? That's the correct answer to this problem.

Thank You,
-C

PS where's the awesome new version that's been coming out any day now...
Last edited by S3D-Jake on Wed Jun 10, 2020 12:50 pm, edited 1 time in total.
Reason: not a bug

S3D-Jake
Posts: 771
Joined: Wed Jun 20, 2018 12:45 pm

Re: bug: support pattern tied to platform - not model

Wed Jun 10, 2020 12:50 pm

As with infill, this is by design. I'll document this for our development team to consider as an option in the future.
"A bird does not sing because it has an answer. It sings because it has a song."

billyd
Posts: 196
Joined: Mon Jan 19, 2015 12:13 pm

Re: support pattern tied to platform - not model

Thu Jun 11, 2020 10:35 am

Wow this is an amazing post, dead serious. I had no idea this is why this happens! I never even thought to shift the model around on the bed. It's so completely arbitrary it never even occurred to me as a possibility of why sometimes things don't get supported. Thanks for this, this is a great help to me to avoid manual supports if possible.

zemlin
Posts: 319
Joined: Mon Feb 01, 2016 11:36 am

Re: support pattern tied to platform - not model

Thu Jun 11, 2020 12:58 pm

This behavior has been clear to me, and I'm not sure I'm hip on getting it "fixed". By shifting the model around I can tweak the support so it lands where I want it to. Who's making that decision if the support becomes smart? Creating the logic to evaluate every different possible structure that anyone will ever want to print, and determine the optimal orientation and position for the support seems like a pretty tall order to me. Having to nudge a model a bit so the support lands better based on what I want is a pretty minor inconvenience.

billyd
Posts: 196
Joined: Mon Jan 19, 2015 12:13 pm

Re: support pattern tied to platform - not model

Fri Jun 12, 2020 11:30 am

I don't disagree I don't mind moving the part around. I just wish I knew about that over the several years I've owned the program. Not too observant lol.

User avatar
dkightley
Posts: 2226
Joined: Tue Mar 10, 2015 4:09 pm

Re: support pattern tied to platform - not model

Fri Jun 12, 2020 12:28 pm

You've obviously not been keeping up-to-date with things by reading the forum on a regular basis. This subject has been discussed at least once in the past couple of years.
Doug Kightley
Volunteer at the National Tramway Museum http://www.tramway.co.uk
Railway modeller and webmaster at http://www.talkingtgauge.net

Return to “Feature Requests”