simplify 3d model has hole in preview mode

I create a process and hit prep to print and Im show a blank model space, and no slicing, as if the software thinks nothing is there.

So now, no matter what model i put into the program it won't slice it, I have tried models Ive sliced before, thinking it was the model and no. So i uninstalled and re installed figuring maybe I need to fresh install 4.0 it would only show the bottom slice, no matter what I did it would not show the top, it assumes I've cut the model in half and it keeps putting a top layer. Si I figured ok well that was good enough for what I wanted to split, so I split it, altered my processes and hit prep to print, and selected both models. I figured ok maybe that was just how it works, it only goes up 43 mm and no higher. It would only allow me to split a model in half up to a certain amount. I could salvage the print by re-pausing manually, sending a homing command from Octoprint's terminal, then resuming again.So I upgraded to 4.0 and immediately had issues, the variable settings wizard didn't work. Thought it would then rehome X/Y when resuming but it didn't. One little bug with it - I only noticed maybe 15mins after it paused, and it seems it will disable steppers after a while - which means you'll move the print head when pressing the lever to reinsert filament. The latter allowed removing the bit that was still in and reinserting a clean feed. Print paused when filament was about 1cm after ithe sensor, you get a page that allows you to either resume straight or go to the filament change wizard. On another note I've just validated my filament runout sensor works, stupid spool with tangles and I broke the filament while untangling during the print. So yup, seems I won't need to use that money back guarantee.

Oh and it was also 30% faster at giving me that better result.

Left the 120 height/150 width/50 speed defaults for first layer. and it was perfect, supports removeable just as you'd expect, clean surface, and also better overall look of the entire part. So bought S3D, spent 20 mins copying the C2 profile for the R2 and adjusting dimensions/adding a heat controller for the bed, porting my startup Gcode, reprinted the part. One part today is trashed becasue the support is basically impossible to remove. Even on 0.1 when you manage to remove it looks crud, and from the actual bottom part, not the support residue. I actually just purchased S3D this afternoon after printing a couple of parts with supports these past few days with Cura - Found that you pretty much have to change the vertical separation to 0.2mm if you want to be able to remove them, and there the bottom of the part looks crud.

Simplify 3d model has hole in preview mode