When STL is loaded Z position is not zero
 
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Pedja
(@pedja)
Trusted Member
When STL is loaded Z position is not zero

I noticed that after I load STL into PrusaSlicer (2.2.0) x and y positions are zero but Z is not zero. It seems it is always half of the height of the object.

It happens even with all default profiles, so no customisations.

I can bet this did not happen before. I noticed this as I was going to do some stacking and then I needed exact height.

Is this something I did somewhere in configuration or this is normal?

Posted : 16/07/2020 9:32 am
Neophyl
(@neophyl)
Illustrious Member
RE: When STL is loaded Z position is not zero

Can you please clarify your 'issue' ?

The centre of a loaded object is its own 0,0,0.  Normally by default slicer will place the object into the centre of the bed.  So if I load in a 20mm calibration cube for example the co-ordinates of the object will be 125,105,10mm (assuming a MK3 printer).  The centre of the object matches the x/y centre of the bed.  This is entirely normal.

As you can manipulate the X/Y freely you can of course change the location by moving it around the bed.  If you moved it to 0/0 on x/y then the edges of the cube would be at -10/-10 and outside the printable area.  As the Z height is locked to put the object in contact with the bed then you can not adjust the z height from the 10mm (for a 20mm cube in this case) unless you have it added as part of another object. 

In that case then the Z height is also freely editable too, which is how you can stack objects in slicer.  While there are many voices trying to get the z height restriction changed as yet (version 2.2.0) this has not been changed.

Its been that way for all versions of Prusa Slicer.  I'm having trouble recalling if Slicer PE did it differently though and I really cant be bothered to hunt up an old copy and install it to check 🙂

Posted : 16/07/2020 11:15 am
Pedja
(@pedja)
Trusted Member
Topic starter answered:
RE: When STL is loaded Z position is not zero

That makes sense, I mean explains what I noticed.

Other than that I see it quite odd. Those numbers are important only if user has to manually arrange objects on sheet and this forces him to deal with odd numbers.

I realized what confused me. When I deal with single part on sheet I see this odd Z, but if I have several parts of the object, object has odd Z but parts have Z as zero (as it is relative to object's zero).

Thanks a lot, mystery resolved.

Posted : 17/07/2020 11:53 am
Neophyl
(@neophyl)
Illustrious Member
RE: When STL is loaded Z position is not zero

I have done a lot of experimenting but when it comes to parts of single objects theres also the drop down for co-ordinates that lets you choose local or global.  That will probably change whats displayed as you are settings the co-ordinate system.  With single objects I dont think it makes a difference.

Posted : 17/07/2020 2:58 pm
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