Wednesday, May 28, 2014

Open letter to slicer makers

There's a lot of talk about this hot new slicer called Simplify3D. Simple to use but easy to configure. Hey, I'm all for that. MakerWare is a nightmare to configure. Plus any tie I can sever with the big jerk Makerbot the better. However, I did a little exploration with the help of some friends and discovered some things that MakerWare does that other's don't, things I've come to rely on, that makes me hesitate to pull the trigger on a new slicer.

So if the Simplify3D people, or anyone else writing a slicer for that matter, wants to know what it will take to win my business here is a very short list:

Easy to use, easy to configure. If I don't have to open a text editor to change filament diameter I'd be very happy. (Of course having a mod to my machine that measures the incoming filament and adjusts on the fly would be even better, but that's neither here nor there.)

Implement spurs. In the image above Simplify3D on the top and Makerware on the bottom are slicing the same test model I made a while ago for 3DHacker. The wall at the bottom was designed to get too thin to print by conventional means. Most slicers, Simplify3D included, give up and leave a gap. MakerWare uses a technique they call "spur" to make a single shell thick wall. It doesn't always work and it doesn't always make the best result, but it's been the key to success on more than one soap stamp in the past. Plus it fills in that gap that occurs when a wall is just the wrong thickness. I need spurs.

No extra shells on fill areas. This one noone is doing, but discovering someone is doing it would erode my hesitation to nothing (provided they're doing spurs).

Shells create ugly prints. You end up with nested acute angles that can't fill in. The feel of the top surface changes where it goes from drawing shells to filling in the layer. (Simplify3D's shell fill option addresses the second point, but not the first, and I suspect causes the gap problem mentioned in the last point.) One easy way to address all these problems is to reduce the shells on your print to 1.
I took one of the Squirrel Squabble tokens to demonstrate this. The token on the left was sliced with 2 shells and it's a mess. Wall gaps and tight angles where it doesn't get the second shell in there. Mess. But on the right the model was resliced with only one shell and looks much better. However with only one shell the infill areas on other layers don't have much between them and the outside of the print which can cause structural and delamination problems. So why can't we have both? Single shells adjacent to the fill areas, and as many shells as we want adjacent to the infill areas?

There is it. Short list. Easy to use, easy to configure, spurs, and no extra shells on fill areas. Anyone who makes those three things happen and I'm all yours.


  1. My personal workarounds in S3D:

    Spurs: well, usually I'd just edit the model to make it easier for the printer. If that isn't an option for some reason you can also: change extrusion width so it interprets thinner walls as printable. If you really need to you can use multiple processes to isolate just the part you need printed thinner.

    Single shell on non-fill areas: if your issue is flat objects with a flat layer on top that have too many shells, you can just tell your print to stop just before that top layer Z height, then make another process starting from that height for just the top layer to print any way you want.

    I have an object that uses multiple infill patterns and various extrusion widths for cleaner top fill throughout the parts of the model that need it and more precise details on symbols and lettering.

    There's solutions to your problems, and so far every problem I could think of in S3D, you might just need to implement some things manually instead of relying on the slicer to guess exactly what you want.

  2. I'm not sure your solutions to the spurs will work, but it's nice that "a" solution exists. That's not as good as a default option you can use easily, which is what I'd like.

    What about patterned infill? I found out about S3Ds line infill and I gotta say I'm not in love because I really don't like line infill. It shrinks and pulls on the print and can cause problems, especially when you're only doing one shell.


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