Dragging in the Z direction does not work  

RE: Dragging in the Z direction does not work

Posted by: @anthony-o5

I have two objects on the 'plater', I assume this means 'platen'.

The name actually originated with Slic3ron which PrusaSlicer is based. From that page:

Slic3r has a tool, called Plater, which allows one or more models to be loaded and arranged before being sliced.

I believe it has to do with the idea of placing objects to be printed on a plate so they can all be sliced into common layer gcode commands. A 2014 Hackaday article provides some background:

Plater is a software that can generate the plate for you, it can import STL files, with quantity and orientation, and it will try to create puzzle the parts to create at least plates as possible, given some parameters sucha as plate dimensions, parts spacing etc.

That module does the "plating" (arrangement) for you. I assumed it was an error myself early on.

I click on the Move icon to drag the currently selected object.

I can move it in X and Y, but Z always snaps the object to the plater.

Is this a bug, am I doing it wrong, or is this a feature?

It works the same way with a single part. You also can't elevate (float) the part by manually entering a Z position in the Position box. Simplify 3D and other slicers have a "place part" function. I think this is really a feature that just isn't working as expected. The part does need to be on the bed to print, but you could find a case where you want the entire thing supported. You can rotate the part so only a small edge is on the plate and the rest supported. If you just want to raise the part off the bed, a raft (ugh) might work. Otherwise, I think you've got a bit of an edge case in that you want to position the part such that it can't be printed successfully in most cases, and there was probably a design decision that it would be better to avoid accidental floating parts than allow them. Not sure why there's not an override though, other than such a thing just not making it up the ever-growing ToDo list.

If you really need such a capability, perhaps you can design the part with a bit of "dummy" shape at the bottom and elevate the rest?

RE: Dragging in the Z direction does not work

This is a "feature" (though it might not do this for STL printers, I haven't tried). Plicer expects that you can't start a print in mid air, so it does what it can to stop you from doing that. If you want to force it, you could add a primitive shape to your object. Select the primitive part and move it away from your model, and then use the drop to bed icon:

Now select the part that is your original object and you can now freely move it vertically. Here the small orange cube is my primitive, and you can see Buddy's feet hovering over the bed:

If I tried to slice this without supports I would get an error because I'd be trying to print Buddy in mid air. But once I turn supports on:

Don't know why you would want to do this though... Adding a raft is easier.

RE: Dragging in the Z direction does not work

It’s part of the underlying logic that you can’t print without some part of the object being on the bed. There’s a big thread on Github with people complaining about it as it’s different to every other slicer out there. The thing is though that doing what sembazuru says is easy and works, and it’s very logical when you think about it. 
if you accept that it’s physically impossible to print without something touching the bed then with a multipart model you can place the bottom first and then place the other parts on top to stack them wherever you want. I think most people just don’t get the add to model function where you can logically add a part to an existing object and once placed Slicer then treats it as the same object when it comes to slicing. 

it’s the same logic when adding parts for manual support, if it’s not part of the same group then slicer will auto generate supports through the model as it’s treats them as separate objects. You just have to understand and use the model heirachy. 

RE: Dragging in the Z direction does not work

Thanks to all; the word 'plater' was unfamiliar to me, it seems to be part of the 3DPrinting vocabulary I have not encountered, and so I thought it was a typo!

As for the models, they started off life as .svg files, then imported into openscad, exported as .stl files, then pulled into PrusaSlicer.

The upper part of the model was (unintentionally) translated to a Z of 2mm, and when converted to .stl it did not land on top of the base properly, hence the attempt to use Move Z in PSlicer to fix things.

Once I discovered the 2mm Z offset in openscad, I set it to 0, exported to .stl, and back to PSlicer.

The upper part of the model now rests properly on the lower part of the model.

thanks again, this my first time posting to the forum, and you all have been most helpful!