First layer under bed when negative z offset is set  

RE: First layer under bed when negative z offset is set

Is it just me who is having this problem? Is this a bug or a new 'feature'? 

Am I missing something obvious?

RE: First layer under bed when negative z offset is set

In Slicer, my offset is ZERO.

Only the Live-Z value on the printer needs to be negative (Mk3/s models).

RE: First layer under bed when negative z offset is set

First picture shows 2.2.0. The other 2 show 2.3.0 alpha 3. In 2.2.0 bed was transparent and you could see the raft even if it is below bed (which I didn't realise before). In 2.3.0 alpha 3 bed is not transparent and you can only see raft if you look from below the model. 

I liked it better when bed was transparent.

Different z offset might sometimes be needed for different filaments, for example PLA sometimes needs to be squished more than PETG for the first layer to stick. I don't want to change the setting on the printer every time I change the filament type. I would much prefer to have different z offsets set in different slicing profiles.

So, is there a way to make sliced model appear on the bed even when negative z offset is set? If not is there a way to make bed transparent like it was in 2.2.0?

RE: First layer under bed when negative z offset is set

The bed transparency change was deliberate from what I read on one of the github issues.  

You might want to read this closed issue, https://github.com/prusa3d/PrusaSlicer/issues/4496 .  I dont know if the advice in there will work for you but its worth a try.

RE: First layer under bed when negative z offset is set

Thank you, that should work.

So, instead of setting negative z offset in printer settings tab I added a G206 Z-0.255 in my filament start G-code. 

After making this change slicer correctly shows my print on the bed and I don't see a reason why my printer shouldn't print exactly the same as before. Will test this in practice next time I need to print something.

RE: First layer under bed when negative z offset is set

Why are you slicing with a negative value? Some sort of user side print sheet compensation ?

No matter - seems you have it under control. Regards.

RE: First layer under bed when negative z offset is set

@witor

Z minus values usually indicate danger. Just make sure that the gcode does not contain any Z minus values, otherwise the nozzle will scratch the printing bed. Not much can happen with X/Y minus values, but Z minus is always dangerous and not common in 3D printing because Z0 or the print bed surface is the starting level 0 and Z always moves away from the bed in the direction of plus.