Lift Model Off Build Plate

[CrazyIvan2 1]

I'm using Cura 5.3.0 on Linux, with an Entina Tina2 printer.

 

I want to improve the clean-up of the undersides of prints by raising the model off the z=0 plane, and thus have support structure under the entire model.  I've turned off snapping to zero and set z=10mm (say), but although the Prepare view shows the model off the bed, when I slice and view Preview the model is back on the base (with a "ghost" of the model shown where it should be).  Scanning through the layers in Preview shows the build at z=0.

 

Some Google results say that's what to do, but others indicate the z offset is to make the printer start on top of an object placed on the print bed.

 

What to do please?  I don't want to just "suck it and see" without some advice.  Thanks.

[obewan 37]

There is a setting in 'mesh fixes' called 'remove empty first layers' try de-selecting that.

 

 

[CrazyIvan2 1]

It's interesting you mention that, because I found it too.  However, although it's ticked to be displayed in the menus in Preferences,  I can't actually find it in Print Settings!  Why would that be?

[CrazyIvan2 1]

Aha!  https://github.com/Ultimaker/Cura/issues/15505

 

Quote

This is a known bug in the last couple of versions of Cura. There is a workaround.

• Disable "Generate Supports"
• In the Mesh Fixes section disable "Remove Empty First Layers"
• Re-enable "Generate Supports"

The setting is improperly hidden when Generate Supports is active.

 

[CrazyIvan2 1]

🙄

 

The above gave me exactly the preview I wanted.

 

Unfortunately the resulting GCode upset my printer (Tina2) to the extent that it tried to print the adhesion raft below the level of the bed!

 

UPDATE: False alarm!

 

I spent ages looking at the GCode and comparing it with a previous run (without the model's Z offset), and couldn't find any significant differences.  So I prepared to re-run the same print file.

 

By a strange coincidence, the Tina2's z offset calibration had gone awry.  I recalibrated it, and the print is now proceeding correctly (apparently).

Edited August 11, 2023 by CrazyIvan2