Converting STL/Mesh to solid

[ga54del]

Hi,

I'm trying to convert a STL file to a solid model. I've tried Mesh to BRep but it just gives me an error message saying that the mesh contains a large number of facets and the conversion has been aborted. I also tried the mesh enabler for Inventor (crashes) and to convert the STL to a quads OBJ with ReMake ("Exporting model..." and after 12 hours with I aborted it).

Is there any other way to convert a STL to a solid?

[wilkhui]

Hi there - can you attach your STL file?

What do you intend to do once you have made the conversion?

Thanks,

Indy

[cekuhnen]

@ga54del @wilkhui

Few observation. If you try to remesh it from triangle to quad and remake takes hours then I assume the model you have has multiple millions of polygons.

You dont really want to convert an STL into Solid anyway. This is a shortcut that is possible but 99% only leads later to issues.

You can for sure load the STL but then rebuild it with the Fusion modeling tools.

That is the proper way to generate clean geometry which you can further refine.

Also the more complex the polygon model the bigger the solid file and the more Fusion will receive a dramatic UI screen refresh drop.

[ga54del]

Here is the file I'd like to convert.

I just need to perform some basic manipulations. I'd like to create a sketch on one face of the body and extrude the sketch, ceate a offset etc.

The mesh consists of "only" 447204 triangles. Might be that my computer is not the fastest but it has at least a Core i7 6700K and 16GB of DDR4 RAM.

[cekuhnen]

@ga54del

thanks for the model. I see now what you want to. This model has around 500k faces and that is simply too much to expect Fusion to be able to convert it to NURBS and be in addition able to navigate the model.

[TrippyLighting]

I am wondering if you have searched the Forum for possible answers before asking that same question that's been asked 1000 times already yet again.

Just typing the words "stl solid" into the search bar in the Forum these threads come up:

Don't get me wrong. I do like to help people make progress, but that requires that folks have done at least a little homework before asking questions!

[ga54del]

this is something you always hear on any forum and normally I don't give an answer but let's see...

for reassuring you, yes, I indeed did some research.

I found that I could convert a quad OBJ to T-Spline in Fusion 360. So I tried to convert it to a quad OBJ with ReMake. Did not work. I searched for alternatives and found a post which said I could just use mesh to solid in Fusion 360 - which did not work. I moved on and tried Meshmixer to create a solid - didn't work. I downloaded the mesh enabler plugin for Inventor - it just crashes every time (as some comments say) etc.

See, I know that somewhere on the Internet there might be a solution for my problem but since I never worked with mesh before I don't have enough experience to tell whether some solution could work for me or not. So I probably would have to download and test every single AddOn or software or Workaround until something works. Do you know how much time this is going to take between doing research, downloading, installing, testing, restarting because Fusion, Inventor or whatever crashes, playing with the settings and evaluating the outcome? I can tell you, it is going to take a long time.

And just for example:

your first result is mesh to BRep - doesn't work.

your second result is mesh to BRep

your third result doesn't provide a solution. Just that Mesh to T-Spline won't work with triangular STL's

4th is mine - that one is going to help me a lot 😉

5th is mesh to BRep again.

6th has no definite solution but speeks of BRep, T-Spline and again a new Software which was used 3 years ago and is extremely slow but it's true, I haven't tried that one yet.

7th is mesh to BRep

8th is mesh to BRep

...

You see, I did my homework. But for being honest and especially since you like to help people make progress, how long am I supposed to search and try before I should post something on the forum? And a little more provocative: why should I spend hours and hours reading posts which offer no solution, always the same solution or a solution which is not applicable for me when I have the opportunity to ask my specific question here on the forum? Since you like helping people and have seen that same question 1000 times, I am pretty sure you should be able to answer the question in less time than it took you to do and post the screenshot of these results. If you do not know the answer this could possibly mean that my question might not have been discussed quite that often.

In any case, I'd love to find a solution for my problem and of course it would also be sufficient if you (or anyone) just provides a link with a solution for my problem. But please not a screenshot of a list of the first results of Google or the forum. This is just ridiculous useless to me and anyone with the same problem who might read this in the future.

[PhilProcarioJr]

@ga54del

I can give you an answer but you won't like it.

Answer:

What you want to do can not be done by Fusion 360 automatically.

If you decide to do it manually it's going to be a nightmare, and more work then any of us can give you without some one on one tutoring that last for several weeks.

There are other apps better suited to do what you want. Blender comes to mind, but in the end you still will not have a CAD model.

Fusion can not deal with 500K polygon models...period.

[dieselguy65]

depending what you plan to do, and how intricate the modifications are/

i have had great success, using TINKERCAD to modify existing STL files.

its super easy. but you are not going to generate intricate models with it, at least not very easily.

but minor mods it works great.

i just done a very short presentation at our county library for my club, on doing this, after i had maybe an hour using the software at most.

[TrippyLighting]

I am glad to hear you did some research.

Here's the number one reason why you should try to spend hours of research of find a solution:

You'll learn something in the process of reading thread upon thread and post upon post. At some point in time you'll be able to connect the dots.

The limiting factor here is knowledge, subject matter expertise  of which you don't have enough at this point in time.

There are things that can be done with .stl meshes, but the devil is in the details. Literally 😉

This Vehicle body has relatively large surfaces without a lot of detail but then has localized details. Any automatic conversion into a quad mesh would either not capture that detail, or would be much to dense to be practical to handle and modify, at least in Fusion 360 where you cannot really make face groups.

 Another real problem is that you mesh is not closed and only describes a surface. It won't for example 3D print in this form. What were you going to do with the mesh ?

You can manipulate dense .stl meshes in likely Meshmixer, but these operations are likely to be very CA accurate.

You could re-topologize this mesh, but in that case it might even be easier to remodel it in a mesh modeler like Blender from scratch.

I don't get why so many people use .stl files when better format are available.  The .stl format was never developed to exchange data between CAD applications.

[dieselguy65]

wow.

you arent helping yourself here.

honestly, all those methods you came up with you could research and try, in a fourth the time it would take one of these very knowledgable gentleman to one on one tutor you on how to do this.

fusion just really isnt the software to be editing stl file car bodies.

find the STEP file for it, you be way ahead.

and lose the attitude.

both of the guys who answered you, have been very knowledgable in my time here.

they have helped me thru simple issues i just couldnt get thru.

[dieselguy65]

TRippy,

my limited experience, STL files are what is shared on 3d printing sites, they seem to be wildly popular in that community

but they darn sure dont make good cad models.

l have tried, and failed many times at using them.

[davebYYPCU]

Actually it's the other way round, generally speaking,

The non commercial - desktop 3D printing machines are limited by their processors, - systems.  Can't generalise too much, 

They process the model into small straight lines, due to the fact they can't manage radius curves, (G02, G03, with the I, J, K parameters),

so Cad models are dumbed down with STL format, to run this type of machine.  Huge community involved sharing designs, etc.

To convert Stl back to Cad formats for Mills and Routers etc, is part of the trend we are seeing.

My 2 cents....

[David_Ewen]

I have the same problem.

I've never been able to convert a STL file.

Mine is attached.

[mgcain05]

His long response was to TrippyLighting who was no help at all! I thought his response was great! Lose your attitude...... you arent helping either 🙂

---

@dieselguy65 wrote:

wow.

you arent helping yourself here.

honestly, all those methods you came up with you could research and try, in a fourth the time it would take one of these very knowledgable gentleman to one on one tutor you on how to do this.

fusion just really isnt the software to be editing stl file car bodies.

find the STEP file for it, you be way ahead.

and lose the attitude.

both of the guys who answered you, have been very knowledgable in my time here.

they have helped me thru simple issues i just couldnt get thru.

---

[TrippyLighting]

Great introduction to the community with your first post!

I've provided nearly a thousand solutions to other users problems and have gone to great length to explain how and why things work and sometimes don't.  What have you contributed so far ?

[Anonymous]

What the hell ?

Guy is asking an honest question, did his homework, wants to learn, and obviously you dont know the answer - so say it, theres no shame in this.

Instead, you are avoiding and send him for a goose chase, then WITH THE ATTITUDE tell him to "loose the attitude" and in the end asking newcomer how much he contributed because you gave ZILLION answers - which is clear statement "I'm so wise, I'm so guru so I can ashame you and treat you like ****"

First:

He needs to learn first and then he would be able to contribute.

Second:

A thousand answers does not make you Alpha and Omega and untouchable.

Third:

Loose the attitude - he did not tell you to "f-u-c-k you", he should, I would....

Fourth:

Get off the high horse, maybe you gave a 1000 answers but you HAVE FAILED MISERABLY THIS TIME.

Signed:

Another guy who searches and finds forum and internet buried under worthless "search google" answers.

EVERYONE SEARECHES GOOGLE FIRST !!!! BECAUSE OF YOU WE CANNOT FIND THE ANSWER !!!!!

[TrippyLighting]

Granted, my first reply wasn't exactly most welcoming. We all have better and worse days!

I can assure you, however that I would NEVER step into a forum and with my first post would yell at a senior forum member and make all sorts of accusations and ill conceived  assumptions based on one forum post.

I do know many aspects of that answer! But as another forum member has already answered, you won't like it!

Fusion 360 cannot convert triangulated mesh files with a large number of triangles into a solid bodies. The limit is set to 20k polygons. Past 10k you'll already get a warning.

The reason is that a mesh, mathematically and in terms of data structure is pretty simple.

CAD software however, works with mathematically precise surfaces BRep and NURBS. These are much more complex and heavy on data.

When you convert that mesh into a solid body, every facet, every triangle of that mesh is converted into such a mathematically precise surface an that simply is too taxing for Fusion 360.

That leaves you with a number of more or less laborious alternatives.

Remeshing. There are other software packages that provide a semi-automated way to convert triangulated meshes into quad meshes:  Autodesk Remake (I believe this is only available at a subscription level), InstantMeshes. ZBrush and 3Dcoat have great re-meshers and there are a couple of plugins available for Blender.

However, depending on the mesh this might work OK, or not so much.

Re-topology. This is manually creating a quad mesh with the help of re-topology tools such as Topogun or the RetopoFlow plugin for Blender. Several Sub-D models have re-topology tools builtin e.g. Houdini, Modo (I believe). This requires a lot o manual work and definitely some skill.

There are two main difficulties in reverse engineering a CAD solid or surface  from a triangulated mesh

1. A mesh has a finite resolution as opposed to a mathematically precise CAD surface. That is in essence lost information.

2. CAD models, and Sub-D quad meshes have topology. Triangulated meshes also have ben stripped of that information.

Thus it ( still yet) requires human skill and knowledge to reverse engineer a good solid model from a triangulated mesh.

I am not saying that you were looking for an easy button, but there definitely isn't an easy button here.

I can also assure you that all that information is available on the internet. That's where I found it 😉

[AaronJHardin]

I know this is an older post, but I feel your pain. This is a common question and there are a lot of tools to address it. Check out this walkthrough. He uses Autodesk Recap to make a Quad > T Spline > BRep. The BRep is a full Fusion360 model.

 https://www.youtube.com/watch?v=8qTx_9HK7IM