bottom solid layers on, but not for first layer?

[bourgoynestudio]

ok, new problem:
why, if I set a process to print only solid top layer (1) and solid bottom layer (1), with no perimeter (Outline/perimeter shells 0), does it print most but not all of the layers solid, but if it also has 1 perimeter on, it doesn't?

I was trying to force printing bottoms and tops before perimeters by having them separated into two different processes, but the result was a mostly solid object

[jimc]

what you are trying to do here is reaching the limit of fdm printing. you cant print a single shell with zero infill at high layer heights then expect the bottom of the mushroom thing to be filled in. to make that shape the extruder needs to step over further than your extrusion width so you seeing gaps. its just the way it is. you need to give it more in some way. it can fill the gaps in with bottom layers OR shells by either turning bottoms on or bump up the shell count to 2 or 3. you can lower the layer height a bit so the gap is divided by more layers which will add additional perimeters, increase the # of perimeters OR put bottoms on everything. your asking a slicer to do the job but your not giving it anything to work with here. for a test drop the layer height on the mushrooms to .2mm, slice it and have a look. those gaps are now divided up enough that there are enough perimeters to fill that. you would still need support there of some kind but they will be filled. as for your other issue, why would you print infill with no perimeter. that wouldnt even make a usable part of any kind. your confusing the crap out of the software.

[bourgoynestudio]

Yes, exactly, I am trying to use fdm printing at its limits. That is where its greatest advantages are. Its most powerful asset, especially in contrast to subtractive fabrication methods, is in that it slices a solid object into perimeters and builds them almost out of thin air. If we could just route the paths more efficiently, we could print a lot faster and with a lot less material. The extruded bead has some amazing bridging capacity that is just being underutilized. I am just trying to find the maximum capabilities of this slicer, which I have so far been very impressed with. With just a few more features in selectively controlling the number of perimeters, and in ordering the sequence of print paths, it could really rocket.

I actually found a very good, fast work around this morning. I'll experiment and see if it works.