Thar she blows

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jsc
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Re: Thar she blows

Post by jsc » Sun Apr 20, 2014 4:45 pm

jimc wrote:Tim, in the new version you have a setting to take your selected supports and inflate them a bit to cover that in between gap that can get missed from the end of one support to the start of the next one.
I'm not sure what you mean, Jim, but that's not quite right. Or at least, not entirely clear....

S3D puts down support in a grid pattern, like rectilinear infill, with a spacing that you can control. The grid spacing is not modified by the new setting at all.

The flaw that the new setting is intended to paper over is that the automated support is only specified for those grid locations in some not-entirely-apparent way that can leave areas that really need it (overhanging arcs and corners) uncovered. The "extend supports" setting takes the automated supports you would get, and just increases its placement by n millimeters in every direction in the x and y plane. You use it to try to make sure the supports cover everything it needs to.

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jimc
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Re: Thar she blows

Post by jimc » Sun Apr 20, 2014 6:30 pm

yes jin what you said is pretty much what i was trying to....lol It enlarges the support to cover areas that might not get covered because you havent activated the next block in the grid so to speak. it leaves areas that might not get covered. there was a recent topic on the s3d forum on this which im sure you read jin but tim probably didnt.

http://www.forum.simplify3d.com/viewtopic.php?f=9&t=796

ketil
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Re: Thar she blows

Post by ketil » Sun Apr 20, 2014 8:31 pm

For what it's worth, I think slic3r started doing a pretty good job of supporting the outer perimeter of protruding features a while ago.

https://github.com/alexrj/Slic3r/issues/1295

Tim, I'm curious what sort of prints you get bad support for in slic3r. I don't use a lot of support, but I would like to understand slic3r's weak sides better, and I think I'd be able to convince Alessandro to improve slic3r's behavior if I can describe the problem accurately.

jsc
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Re: Thar she blows

Post by jsc » Sun Apr 20, 2014 9:27 pm

ketil, here's an example of what turned me off using slic3r for anything that required supports in the past:

https://groups.google.com/d/msg/makerge ... rMRkqUVtoJ

That thick circular shell on the left was basically welded to the part. The new pillar support on the right looks much improved, but now there are issues with thin walled objects: https://github.com/alexrj/Slic3r/issues/1875

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Tim
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Re: Thar she blows

Post by Tim » Sun Apr 20, 2014 10:15 pm

I feel like apologizing to my machine.

I just purchased S3D, and now I realize how I've been abusing my M2 by feeding it crap that came out of slic3r. I have been working on designing and printing a model car, and I just fed S3D the part that I thought would be the hardest to print, and it gave me the most beautiful print I've seen for ages. No longer is the M2 spending all its time doing retractions and dropping pointless miniscule dots of plastic in seemingly random places. And this is with doing nothing more than selecting all the defaults! I am truly impressed. Now I understand why that whale of yours came out looking so nice.

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jimc
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Re: Thar she blows

Post by jimc » Sun Apr 20, 2014 10:35 pm

Yeah tim i love it. its not perfect. It does have some flaws but every release they come out with it truly gets better and adds some real nice features

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Tim
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Re: Thar she blows

Post by Tim » Mon Apr 21, 2014 2:57 am

Hello Ketil,

I expect that in the long run, if I took the time to understand every aspect of slic3r and tweak all the parameters just right, I might be able to get the same quality as S3D Creator just did for me. The difference is that Creator seems to know what's right to use in every situation that I've thrown at it (which is admittedly limited to what I was working on today).

Here are my problems with slic3r, and please advise me if I have been missing something obvious. But I have not seen much difference between slic3r versions 0.9.8, 1.0.0, and 1.1.0.

(1) Slic3r does a huge amount of retraction. I would guess this is a quality of the algorithm issue---per layer, slic3r can only get the number of paths needed down to a number that's usually in the dozens. S3D appears to get the number of paths down to one or two.

(2) Slic3r generates a huge number of tiny segments that are so small that they cannot possibly make any difference to the print, but because they are separated from the other segments in the layer by a retraction, they tend to cause excessive amounts of blobs and stringing.

Every time slic3r does a retraction, it increases the chance that pulling up the extruder will cause the layer to pull up with it, which increases the chance of layer delamination, and ultimately print failure.

(3) Recently I have tried making rafts in slic3r, and what I get does not look like a raft at all; it just drops down some short lengths of crosshatch lines randomly here and there, sometimes under the print, sometimes not. I did a raft in Creator and it made a solid surface under the whole print. I could choose how dense to make that layer, how many vertical layers to make the raft, etc. I could not get anything like that in slic3r.

(4) I tried generating support structures in slic3r, and they were so close to the walls of the printed part that it was all stuck together, and I couldn't get the support structures off of the piece after it was printed. I looked for some parameter that would let me pull the supports back from the walls of the piece, but I could find no such parameter.

Today I got a complete epic fail in slic3r, where it printed the first layer at 0.1mm and the second layer at 0.675mm (not good!). While this was admittedly my fault (I had two separate structures that were accidentally intersecting, making a non-manifold object), slic3r 1.0.0 just sliced it (wrong) with no comment. At least slic3r version 0.9.8 had the good sense to warn me that I had a non-manifold object.

Sorry this is getting off-topic. I should start another thread on slic3r problems. We are supposed to be admiring a translucent whale here!

Toby
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Re: Thar she blows

Post by Toby » Mon Apr 21, 2014 3:15 am

Tim wrote:I feel like apologizing to my machine.

I just purchased S3D, and now I realize how I've been abusing my M2 by feeding it crap that came out of slic3r. I have been working on designing and printing a model car, and I just fed S3D the part that I thought would be the hardest to print, and it gave me the most beautiful print I've seen for ages. No longer is the M2 spending all its time doing retractions and dropping pointless miniscule dots of plastic in seemingly random places. And this is with doing nothing more than selecting all the defaults! I am truly impressed. Now I understand why that whale of yours came out looking so nice.
Lol, I feel like I should welcome you into the light or something. Then I remembered that just two days I was cursing S3D and telling myself as soon as someone came out with a *real* slicer/printer control package I would buy that in a heartbeat.

On the other hand, the new version actually seems to have addressed some issues and now I'm happy with it again.

So anyway welcome to the gang of S3D users in the Makergear forum.

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Tim
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Re: Thar she blows

Post by Tim » Mon Apr 21, 2014 3:39 am

I was thinking about starting a "friends don't let friends use slic3r" campaign, but I don't want Ketil to feel too isolated. . . I really do support open source solutions. I'm an open source developer, myself (opencircuitdesign.com). But that's for software where the commercial alternatives run in the hundreds of thousands of dollars for a single seat license (per year!). $140 is a tempting price point. But I'd also like to see slic3r meet the challenge of being software that can realize the potential of the M2 hardware. Which it's a bit short of doing at the moment. I would love to contribute to slic3r myself if I didn't have my hands full with other projects. At the moment, my priority is getting good prints, not trying to improve the algorithms that might get me better prints in the future.

jsc
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Re: Thar she blows

Post by jsc » Mon Apr 21, 2014 3:46 am

Tim wrote: (1) Slic3r does a huge amount of retraction. I would guess this is a quality of the algorithm issue---per layer, slic3r can only get the number of paths needed down to a number that's usually in the dozens. S3D appears to get the number of paths down to one or two.

(2) Slic3r generates a huge number of tiny segments that are so small that they cannot possibly make any difference to the print, but because they are separated from the other segments in the layer by a retraction, they tend to cause excessive amounts of blobs and stringing.
I've noticed this as well. When printing something complex with Slic3r, I have to wonder what it was thinking when it came up with that tool path. Jump-dot-jump-dot-jump-dot, over and over. Jump-scribble-jump-scribble. With Simplify3D, with all its faults, bugs and annoyances, at least I can watch the print and see it doing reasonable-seeming things. I think it would be instructional to slice and make available some small but complex object with slic3r and Simplify3D just to showcase the difference.

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