Mesh of stl file is all messed up!! Can anyone help?

**paccap** · 03-02-2016, 11:32 AM

Hi everyone,
I recently made a model that I exported via a plugin from revit (.rvt files to .stl files). I load it into makerbot to find that the mesh is all messed up!!! Trying a quick print shows that the sides of the roofs are not whole for some reason.
Can anyone help!? I have uploaded the relevant files as the attachment way is not working.
https://www.sendspace.com/file/sjj7y3

**ssayer** · 03-02-2016, 03:08 PM

Upload it here and download the fixed file...

https://netfabb.azurewebsites.net/index.php

**Geoff** · 03-03-2016, 12:33 AM

Well, yes you can netfabb your model - but that always doesn't come out right - I uploaded his file to Netfabb 20 minutes ago and it failed to repair it "OOPS, SOMETHING WENT WRONG!"

Try it if you like

Unfortunately Netfab simply reverses faces or 'normals' that are not facing outward, i.e it makes them consistent across the model surface - these are the 'holes' you are always seeing it refer to. They are not technically holes, they are just places in the model where you didn't join vertices or edges correctly. A correctly made model is already manifold

If you make a mesh from scratch, and do it the right way - you don't even need to netfabb your models. You know they are manifold because you created every single vertice of it and made sure when you extruded, bent, pulled or rotated any edge or vertice - the next corresponding face was the same polarisation as the last and edges or 'seams' have no gaps... It's when people copy / paste parts of their model, and Join them together or duplicate parts. This generally doesn't join vertices correctly and just clones the object, distance specified by you... next to the original object.

But.. sometimes Netfabb can't do a very good job, especially when the mesh is a little messy to start with (like this one!)

The issue with this model is pretty much alot of overlapping edges (where vertices were joined together incorrectly) and reversed normals,
hlp1.JPG hlp2.JPG hlp4.jpg

I'd rather show people why they are not printing rather than sending them to netfabb because if you can show them why it's happening, you might actually help them.

**paccap** · 03-03-2016, 10:52 AM

Originally Posted by Geoff

Well, yes you can netfabb your model - but that always doesn't come out right - I uploaded his file to Netfabb 20 minutes ago and it failed to repair it "OOPS, SOMETHING WENT WRONG!"

Try it if you like

Unfortunately Netfab simply reverses faces or 'normals' that are not facing outward, i.e it makes them consistent across the model surface - these are the 'holes' you are always seeing it refer to. They are not technically holes, they are just places in the model where you didn't join vertices or edges correctly. A correctly made model is already manifold

If you make a mesh from scratch, and do it the right way - you don't even need to netfabb your models. You know they are manifold because you created every single vertice of it and made sure when you extruded, bent, pulled or rotated any edge or vertice - the next corresponding face was the same polarisation as the last and edges or 'seams' have no gaps... It's when people copy / paste parts of their model, and Join them together or duplicate parts. This generally doesn't join vertices correctly and just clones the object, distance specified by you... next to the original object.

But.. sometimes Netfabb can't do a very good job, especially when the mesh is a little messy to start with (like this one!)

The issue with this model is pretty much alot of overlapping edges (where vertices were joined together incorrectly) and reversed normals,
hlp1.JPG hlp2.JPG hlp4.jpg

I'd rather show people why they are not printing rather than sending them to netfabb because if you can show them why it's happening, you might actually help them.

Thank you for your response! Netfabb didn't work so I was wondering if you could help me fix this as I have no clue in what to do

**Geoff** · 03-04-2016, 03:43 AM

Originally Posted by paccap

Thank you for your response! Netfabb didn't work so I was wondering if you could help me fix this as I have no clue in what to do

I'll have a crack at it, it's a bit of a challenge now..

For starters, it is enormous.. what scale do you want it at? i.e how big is your printer?

This roof section, the 3 tiers of the roof... they are all at different heights, which means there will be alot of support. I'd suggest seperating them and laying them all flat on the bed.

I'll see if I can make it printable first... it is nearly 400,000 polygons. If I try and un-subdivide any of the vertices, it make the shape of the object screw up, so I will basically delete faces manually and re-create them
as quads.

It won't be fast, i'll get back to you in a few hours...

**paccap** · 03-04-2016, 09:36 AM

Originally Posted by Geoff

I'll have a crack at it, it's a bit of a challenge now..

For starters, it is enormous.. what scale do you want it at? i.e how big is your printer?

This roof section, the 3 tiers of the roof... they are all at different heights, which means there will be alot of support. I'd suggest seperating them and laying them all flat on the bed.

I'll see if I can make it printable first... it is nearly 400,000 polygons. If I try and un-subdivide any of the vertices, it make the shape of the object screw up, so I will basically delete faces manually and re-create them
as quads.

It won't be fast, i'll get back to you in a few hours...

OMG thank you for helping me with this!!!

The revit file is to scale of real life and i was thinking of making it to a scale of 1:150 for my replicator 2. Due to this the 3 tiers would be printed separately in order to print the size i wanted and so it can fit on the bed.
Thanks again!!