Override ""no extrusions on first layer" error message
I have a complex object that I split using connectors.
Post-splitting, I want to create several versions of the object by masking the tops of verious different vertical, cylindrical channels (holes) in the original object.
To do this, I use "Add shape: Box" to create a "patch" that I then size and position to cover the top of the cylinders. Since I don't want the patch the entire length of the cyliner (just the top portion), I use a "Negative volume" to cut out the bottom of the patch -- conceptually, the patch "hovers" about the base plate.
When I slice, I get the "no extrusions on first layer" error message, presumably since when sliced alone, the patch does appear to float in mid-air -- however, combined with the original object, it doesn't so it's not really a problem.
NOTE: I can get around the problem partially by adding a support but that messes things up since the support overlaps with the original object.
Why doesn't Prusa slicer allow me to create the G-code -- which is actually valid?
Why can't it just warn rather than erroring and blocking export?
It seems like I can't merge the patch with the original object -- perhaps because there are connectors.
Also, presumably I don't want to merge objects since I want to be able to move around the added shape to create different versions of the print -- rather than having it fixed.
Is there any way to "override" the error message and save or upload the gcode anyway?
I don't like the fact that Prusa is acting smarter than it needs to be 🙂
RE: Override ""no extrusions on first layer" error message
There is no way to over ride the warning.
You can normally add a Part to an existing Object to make a single Object with multiple Parts, and still move those individual Parts around. However you have to use the object list tree on the right to select a specific Part, as clicking on it in the Platter just selects the combined Object.
I don't know if the fact you have connectors or not effects that as I haven't tried that particular use case and I'm not near a suitable pc to test it at the moment. I rarely use the Cut feature anyway as I prefer to do all my splitting and connectors in the original model in CAD.
I have used the 'patch' method in the past to add a sacrificial layer to the bottom of holes allowing them to bridge but find adding them and positioning them to still be way easier in Blender anyway. The snap to vertice or face makes this a breeze.
While they made massive improvements to the Cut tool during recent releases basically the Slicer tools are just about 'ok' if you absolutely have to use them but anything related to model manipulation is just so much easier to do using other software once you get the hang of it.
Adding/Merging Objects also makes the support work without it going through other objects. PS slices each Object individually. That means it doesn't care and overlapping models (or their supports) will cause 'bad things(tm)' to happen as there will be 2x the amount of plastic in 1x the space. It is up to the user to make sure there is no overlap, although I believe they now added a warning. Its why your 'patches' should also be merged with the object you are patching.
It is this slicing individually that allows it to do different settings like layer heights for different Objects etc. It is also why the merge option (or right click an existing Object and then Add Part) is there.
RE: Override ""no extrusions on first layer" error message
There is no way to over ride the warning.
You can normally add a Part to an existing Object to make a single Object with multiple Parts, and still move those individual Parts around. However you have to use the object list tree on the right to select a specific Part, as clicking on it in the Platter just selects the combined Object.
I don't know if the fact you have connectors or not effects that as I haven't tried that particular use case and I'm not near a suitable pc to test it at the moment. I rarely use the Cut feature anyway as I prefer to do all my splitting and connectors in the original model in CAD.
I just tested and it seems that "connectors" prevent merging -- unless you "invalidate cut info" which I would prefer to do.
I wish that you could override the errors though..
RE: Override ""no extrusions on first layer" error message
I ended up using "invalidate cut" and then merging the added shape.
It's not clear to me why so many operations fail without "invalidate cut" -- it's not clear to me why that needs to be so.
Any thoughts?