Generating support inside infill

[sanslos 0]

I have a large print (10x12 inches at the base) of Chaos Stones by DuncanShadow. I was trying to save plastic and reduced infill to 10% (it still estimates it will take more than a day to print).  As I looked closer at the preview I noticed that there are sections of the actual model (shell, top/botton) that are expected to be printed over infill, but there is no support structure for them.  I was expecting (hoping?) that Cura would be extremely clever and build a platform in one of the infill grid cells, build support on the platform, then build the final shell on top of the support.  But it doesn't seem to do that, it apparently thinks it can print in air 😊

 

  I suspect what will really happen is that it will extrude into open space and wipe the plastic off on the infill grid wall.  Hopefully there will be enough structural integrity that it will complete the shell, I'm not so sure.

 

  This thing is basically a ball (a flattened ball), what is the best way to slice it?

Edited December 18, 2019 by sanslos

[sanslos 0]

Note this is on Cura 4.4.0

[tinkergnome 927]

Well, if you ask for 10% - that's what you get... 🙂

That's probably a case where "gradual infill" comes in handy. I guess this can (kind of) used to solve the problem.

It's explained in the manual:

https://ultimaker.com/en/resources/20416-infill

[sanslos 0]

I had the same issue (but less severe) with any level of "grid" infill, gradual infill is the ticket.  Thanks.

[sanslos 0]

Well, clearly gradual infill is better but it needs tweaking.  With my "30% infill, 5 steps" setting Cura puts lines in space.  It seems to work at the edges, it gets a little weirder as it moves to the interior.