Let's talk about Slic3r support material (Page 1 of 2)

Slic3r support could use some improvement. The only cool improvement I've found is the "support for X number of layers". This has helped me minimize the support fail when I really did need some support.

I have been doing just that.   I'm a Solidworks user and I'm also OK with Sketchup, but most of the models I want to print are either STL, OBJ, or their native format which is usually 3D Studio Max.  You can't inport those formats into Solidworks and edit them.

I find that the simplest way is to add the support using Repetier itself.  Here is what I do:

I made a very simple bar in Solidworks, it's about 3mm wide by .25mm thick and about 20mm long.  After I import the object in Repetier, I also import the bar, then I rotate it and scale it to fit just under the overhang.  I then copy it and place another copy , and another copy until the area is properly supported.  I also found that depending on the height of the support I may have to support the support itself, so I place the copies at 90° to each other and intersecting, so the support is a pretty solid zig zag. 

When I import the support bar, I uncheck the aspect ratio box, so I can scale the support unevenly as needed.  I also do the finer alignment by looking at the build platform from the bottom.

Nice.  I use openscad which can import obj and stl files.  I make cylinders or cones as the support structures which is super easy with openscad.  I like your Repetier method and will likely try in the future.  Thanks for sharing.

instep is free and converts stl to stp. the stp gemoetry can be selected and used as work planes or whatever really.

for the record, i have the same issue with slic3r

Well, it took a while to figure out how and where to post it, but finally did, so the issue is now on the Slic3r Github. 

If you guys are interested in following it, here is the thread. Hopefully we get some answers.

https://github.com/alexrj/Slic3r/issues/1406

Alex is pretty good about answering stuff. However, people tend to ask the same question about 20-30 times a week. Make sure and subscribe to his github page, and read all of the docs for slic3r.

Yes, but at least someone will point to the already existing posts, even if it's just to berate them for not doing their due diligence in searching.

Try angles greater than 90. No support is 180 (think of the angle of a tangent to a circle with axis parallel to x-y plane: top is 0 deg, sides are 90 deg, bottom is 180 deg). That said, I still cannot get it to do exactly what I want. My guess is that slic3r first prunes triangles whose tangent is below threshold, then projects remaining triangles onto x-y plane to find support area, then uses spacing in some way to decide where and how to place support over these areas... So the interplay between these parameters (angle and spacing) is non-intuitive. I'll have to "use the source" (github repo) to see if my guess is correct...

I already tried that.  Anything over 90° generates very little support, usually in the wrong place or only at extremities, adn sometimes the support is incomplete (like it never reaches the part it's supposed to support).  Not only that, but sometimes it takes like 3 times longer to generate the code.  Not very useful in my opinion.

One thing I found useful though is the option to generate support for the first ## layers even when the support checkbox is disabled.  That seems to generate support for the first 50 layers or so, and it works pretty well (like when you have a bottom surface which is not flat or it's slightly above the build surface.  That works OK.  You can input any number you want, but the support seems to top out at around 50 layers.  Additionally, it will only place support that starts on the build platform, and no support above the actual model surface

Ah:
https://github.com/alexrj/Slic3r/issues/1082

Broken in 0.9.10b, fixed in master..

I don't think there are nightly builds. You can either wait (judging by past release cycles, and by the fact that there's just 3 issues open for 0.9.11 milestone, a new release is overdue -- after summer vacation, perhaps or downgrade. If you really want to buld from git, its not too complicated, eg Windows:
https://github.com/alexrj/Slic3r/wiki/R … on-Windows
(Google "slic3r build" for other platforms).

Edit: And, by glancing at source, it seems my guess was way off... For one, threshold applies to angle between layer edges not triangles -- and generally everything is done on toolpaths, not the original mesh?

Edit2: Not near computer, may give STL shot over weekend..