Question I need help with slicing archicad model

[Darkglowing 0]

Hello!

So a friend asked me if i could print him a model 230mm x 230mm x 150mm he created in archicad 25 program for a project he is on. Because the project is to big in real life and the measurements were in meters he downscale it to fit the printers bed size and exported it as an .stl file. When i open the file, the model loads into cura, but the problems occur instantly, first i get a message about error with the model something with mesh tools that the model isnt watertight but it has holes in it logical. But when i try to slice it everything seems ok but i can not print it with roof upside because i would need to make supports everywhere ( waste of material and costly), so i decided to flip it roof first (on the printer bed), and there occurs the next problem, when i flip the model with the roof on the heat bed and slice it, the program doesen't recognize the holes anymore that were i as design implented. I don't understand same happens if i flip the model on the side wall where the holes are too, the holes simply dissapear but are still showing the position. Can someone check my file and tell me whats wrong with it? maybe even try to fix it so it would print roof first. Or must he change something in archicad before sending me the file

Thank you for any help provided!

radenci m1_2.stl

[nallath 1,120]

The default geometry of this model makes it extremely unsuited for 3D printing. The problems that that causes are made worse by the fact that the model isn't watertight.

[Darkglowing 0]

30 minutes ago, nallath said:

The default geometry of this model makes it extremely unsuited for 3D printing. The problems that that causes are made worse by the fact that the model isn't watertight.

So what are the options/solution here to be able to print this model? and what does it mean watertight?

[GregValiant 1,251]

+1.  Before going any further - that model is not repairable.

"Non-Watertight" means there are open seams between surfaces.  In the case of the holes, the cylinders that comprise the periphery of the holes (in the roof and sides) don't meet the walls. 

Consider a wall of your house that you fill full of water.  It will leak out around any electric outlet cover because the cover is not "watertight" to the wall.

 

Tall skinny vertical features (like your walls) are tough to print.  The nozzle itself can knock them around while printing.  If I get stuck HAVING to print something like that then I would build in removeable supports to keep the walls from wobbling as the nozzle travels and as the bed moves back and forth.  My first choice would be to break it down into parts and make it an assembly.  The three separate parts could be printed flat and both PLA and PETG are good with cyano-acrylic Super-Glue.

 

The model still needs to be "watertight" though.  Back to the CAD program for that.

Edited March 1, 2022 by GregValiant

[GregValiant 1,251]

Here is a close up of one of the roof holes (using MS 3D Builder).  The facets of the hole that are highlighted in black look OK.  The red arrows indicate facets that are wrong.  Those "wrong" facets are the problem as they are what is making the model "non-watertight".  There are a lot of those problem areas in that model.

 

[GregValiant 1,251]

BTW - This is the report from the STL repair site (https://formware.co/OnlineStlRepair).  Not good.

When attempting to repair the file, all the roof holes disappear.

--> 104 Naked edges (?)
--> 10 Planar holes (?)
--> 0 Non-planar holes (?)
--> 16018 Non-manifold edges (?)
--> 18179 Inverted faces (?)
--> 0 Degenerate faces (?)
--> 7181 Duplicate faces (?)
--> 0 Disjoint shells (?)
-> Repairing: 100.00%
----- Repair completed in 44801ms ------
-> Vertex count changed from 9688 to 22220 (+12532)
-> Triangle count changed from 29348 to 44622 (+15274)

[Darkglowing 0]

13 minutes ago, GregValiant said:

BTW - This is the report from the STL repair site (https://formware.co/OnlineStlRepair).  Not good.

When attempting to repair the file, all the roof holes disappear.

--> 104 Naked edges (?)
--> 10 Planar holes (?)
--> 0 Non-planar holes (?)
--> 16018 Non-manifold edges (?)
--> 18179 Inverted faces (?)
--> 0 Degenerate faces (?)
--> 7181 Duplicate faces (?)
--> 0 Disjoint shells (?)
-> Repairing: 100.00%
----- Repair completed in 44801ms ------
-> Vertex count changed from 9688 to 22220 (+12532)
-> Triangle count changed from 29348 to 44622 (+15274)

damn, so many errors, i really appreciate for your help and research you do, in reality im lost i dont even know what im watching right now here, but im eager to learn more about since it will help me in future to recognize such kind of things, so the problem lies with the holes how they were made in the first place. Would it help if the holes and the whole model were merged/grouped as a solid object?; i even saw a video where someone is explaing something about using archicad for 3d printing but i don't know what im searching in the video and if it is explained in it. Maybe something is wrong with de-scaling the object so that the details dissapear?

Links to the videos: