Missing sections of a print in Preview

[Raven_CDN 0]

I have an odd issue where random sections are missing in the preview whenever I scale my object. 

Original size is 320mm

I scale down to 210 huge 10-12mm sections are missing,

I scale it down to 150mm 5 mm sections are missing but different areas than the first.

I scale it to Under 100mm everything is fine

Using version 4.8. I appreciate this a complicated item but this is really odd. 

I have not actually tried printing it, I am assuming the preview is accurate. 

Thanks

 

[GregValiant 1,330]

If possible post the STL and also use "File | Save Project" and post the 3mf file as well.  It will contain your settings.

Some models just don't scale well and you are pushing it down a long ways.  Features can disappear because Cura knows the printer can't print them with the current settings.  Why it says it can print at 100mm but not at 210 is odd though.

[Raven_CDN 0]

Yes it is really confusing me considering the empty areas move around depending on scale ratios.  Even tried different exports of the same project, stl,obj, etc...

[Raven_CDN 0]

I just uploaded both of those files.

I uploaded them before any scaling is done. So don't be surprised by the height. 

I would like to print this at 50%.

Thanks Greg.

CE3_Main_Bodymiddle v1.stl CE3_Main_Bodymiddle v1.3mf

[GregValiant 1,330]

When you open a model in Cura and the popup says "The model is not watertight" it means the model itself has errors.  In your case, a lot of errors.  When a surface is red in X-ray view it is facing the wrong way and Cura can't figure it out.

 

Here are two models.  On the right is the one you uploaded and on the left is the same model repaired at NetFabb (where you have to create a free account).  Just upload a model and download it when it's been processed.

 

Here they are sliced.  Missing pieces in the right model.  The repaired model looks pretty good.  Notice how the missing pieces in the right model coincide nicely with the red areas in the Xray view.

BTW I think this needs to be printed on a fair sized raft.  Its so tall and has very little contact with the build plate.  Trying to print this fast could cause the model to fall over of it's own accord.  I'd have accel control enabled at about 250 as well.  Nice soft starts and stops are the way to go.

Edited February 20, 2021 by GregValiant

[Raven_CDN 0]

Thank you very much for your help with this. That makes sense. I will start working to get those resolved.