Is it possible to cut objects without generating walls?

[PlasticPercolator]

I have a large model that I would like to print and (eventually) fill with resin for strength and stiffness.

When I cut the model into parts, walls are created, which is logical for most cases. However, I’d like to leave those sides mostly open so that when the object is assembled I can pour the resin in and it hardens as a single contiguous piece.

I did attempt to use modifiers with zero wall loops (based on some online searches), but these only appear to recess the walls, rather than expose the infill area.

Any advice would be greatly appreciated. Thanks!

[TeamPuddlePuppy]

@PlasticPercolator

walls are created,

Welcome to the community! I’m glad you made a post! Unfortunately, although others are surely more knowledgeable than I am, I do not think that there is a way to not generate walls during a cut.

[RetroSharky]

Let me summarise: You want to make a cut in the slicer while also keeping the infill open?

Yes, that is possible, but it involves a few extra steps and you will lose maybe a few millimetres in the process. First, it is important to select an infill that also supports filling like Archimedean chords

Infill patterns | Prusa Knowledge Base

Then make your cut: Also make sure that you set the checkbox for flip if necessary on an object, for example.

Now you need to set the following settings: Top shell layer 0

However, this approach has one drawback: it only works with objects positioned upwards. Or, to be more precise, the area where the infill should be visible. This means that you have to make sure that the object is actually positioned upwards.

_______

Here is another example:

[PlasticPercolator]

Thanks for the detailed response here!

Unfortunately, the object I’m printing is large enough that I can’t just cut it in half - I have to then cut each half of the object to fit them onto the print plates (at the moment arranging the cut parts ends up on 6 plates).

This means that two of the sides are cut on most of the parts (e.g. in the X and Y directions). It would great if there was a feature where you could select a face or wall and set the wrap number to 0 just for that selection!

I wonder if this is something I should attempt to solve in the source CAD application (FreeCAD) for now. I’m guessing this is not a common request, so I’m not surprised that what I’m trying to do doesn’t work initially

[RetroSharky]

@PlasticPercolator

Unfortunately, the object I’m printing is large enough that I can’t just cut it in half

Take a look at this topic, it might interest you and give you some helpful tips. It also deals with filling and weighting. In your case, it might be more appropriate to simply leave a hole, fill it, and then seal it. You might also want to check out the topic I linked to; there are some real experts there. Maybe ask the question there, but include photos.

Weighted prints. Note to self: Don't use sand while printing!

I needed another storage method for my build plates. I ended up finding this 5 plate solution. It printed OK but I was dissatisfied with the weight. https://www.printables.com/model/529432-bambu-build-platebed-holder-5-slots-trimmed In the past I used ball bearings and steel disks for weight. However, this time I wanted to try out sand since this particular model had lots of nooks and crannies. So I had the second print pause at 4 layers before it was about to close off the top and with a funn…

By the way: In case you’re wondering, to post photos, you have to complete the short mini tutorial and confirm the rules during the process. You should have received a message about it.

[PlasticPercolator]

@RetroSharky

In your case, it might be more appropriate to simply leave a hole, fill it, and then seal it.

Do you mean a hole in each cut object? I currently have 14 objects that would need the epoxy to run through once it’s fully assembled.

Thanks for the link - that was a quite amusing account of an unfortunate situation! I wasn’t planning on doing any filling until all of the prints were done and assembled into the full object.

[RandomKhaos]

@PlasticPercolator

I wonder if this is something I should attempt to solve in the source CAD application (FreeCAD) for now.

It’s easy enough to do. In the Part workbench you can slice up the model into parts and hollow each piece out.

Here are some steps you can follow:

1. Switch to Part workbench
2. Select Create Primitives
3. Select Plane and choose dimensions that are larger than the piece you want to slice
4. Use Transform to move the plane around into the position where you want to place the cut
5. Select both the body you are cutting and the plane
6. Click on Slice Apart
7. This will separate the body into two parts
8. From here you can create more planes and further cut up the model
9. Once that’s done, you can hollow out the parts
10. Hide the parts, minus the one you want to hollow out
11. Select the face you want to be hollow
12. Select Thickness and choose a negative number in the thickness you want the walls
13. Do the same for all the split parts and export.

It’s a bit more involved than slicing up models in Bambu Studio, but you’ll get the results you are looking for.

[PlasticPercolator]

Thanks for the guide! Unfortunately when I get to step 12 I get the error message ‘BRep_API: Command not done’.

[RandomKhaos]

You’ve ran into one of the limitations of Freecad. It was unable to process the thickness step. Could be that the part is too complex for it to calculate the steps necessary to apply the thickness or there’s just a feature somewhere that it’s struggling to compute. Depending on the part geometry, you could clone it, scale it. and use it as a subtractive part to create a hollow body. You can also do that in Bambu Studio.

[PlasticPercolator]

I think I’m more inclined to accept that this is user error I’m working on the model again with this in mind, and I’ll see how things go.