Is it design, slicer or printer

For Halloween I have been printing ghosts for family and friends. They have all been designed using Fusion 360 form mode, in the drawing they appear to be solid. However when I slice them some of the designs have holes in the arms as you can see in the picture. All of the designs are similar. Just one more thing that I have discovered in my 3d printing journey that I don’t understand.

. As always any advice is greatly appreciated.

What Slicer are you using? You should be able to preview the sliced object layer by layer to see if those holes are there. If they are, you may need to go back into F360 to investigate.

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I agree with @bd43, first check your slicer layer view to see if it is slicing properly. If you have a secondary sliver installed try it on both.

The other thing I have run into with Form modelling in F360 is that the shell or surface may only be 0.1mm thick, meaning the slicer wont even try to print it because it’s too thin. If the slicer shows an issue I might check to see if the shell is too thin, I usually use something like the section analysis tool.

Looks like the ghost is hollow with single wall, maybe its a bridging thing. what is your fan speed set at for bridging?

Thanks for the quick response! Just got home from a 2 hour trip down the QEW from Mississauga to Brantford.
When designing I always thicken the form to a minimum of .8 mm so it should be at least 2 lines thick. The other thing is that all of the designs (there are 7) are very similar and it only happens on 3 of them. I was using Cura 4.10.0 and when this happened downloaded 4.11.0 but the same thing happened. If I was going to try another slicer do you have a recommendation.

Wait, You live in Brantford? Where? I’m out by the airport.

As for the the missing ghost parts, is it possible the slicer is being expected to slice a wall thinner than the width of the nozzle?

In Cura, at least, there is a Walls->Print Thin Walls checkbox. I have to use it sometimes to get text to not partially disappear when the slicer would make (let’s say) parts of a “T” thinner than the nozzle diameter and thus chooses not to print it at all.

I suppose, other than enabling this setting, there are two tests for this:

  1. scale the ghost to be significantly larger (say, 200% in each direction) which will have the effect of doubling the element sizes which may make them printable, or
  2. use a thinner nozzle (say, 0.2mm) which will take a lot longer to print, but my manage to print thin walls.

If either of these things solves the problem, then you will need to check the original model to ensure the ghost’s features are all thick enough.

Pesky things, those ghosts.


Thanks for your thoughts. I have gone back to the design stage and made it 3 mm thick and they print fine. What I still don’t understand is why one design would print and another wouldn’t. However I have convinced myself that even though they should all be 0.8 mm thick the design program doesn’t always properly complete the command.
Thanks for your help