Autodesk Inventor?

Hi guys. I work in an engineering company and one of the guys wanted to import everything to inventor. I though i could help him by loading the pieces to Freecad and then exporting to a supported format, but FC throws me a bunch of errors when trying to do so. Has someone came with a complete Mendel90 model in Inventor?

I assume you are loading the scad files into FreeCAD. Did you do them individually? or as one whole file?

I would be interested to know which individual files failed as I am always looking for test cases for ImportCSG
as used by FreeCAD in the process of loading scad files.

Hi Keith,

I'll be happy to assist you. I'm experimenting with openscad and FreeCAD and i'm having an error "Hull not supported" with a file like this one i'm attaching.
Googling a little bit thaught me Hull is not yet supported by the ImportCSG module, which is the most common error i'm getting with mendel90 .scad files.

Thanks yes Hull is not supported.

I have just completed an Open University exam, Monday, with that now out of the way my new priority is to complete my Mendel90 which I started but had to put on hold. But I will have a look again at what is involved with adding support for Hull, but I suspect its far from trivial.

Okay I have done some digging and have added the following append to the FreeCAD developer forum https://sourceforge.net/apps/phpbb/free-cad/viewtopic.php?f=10&t=4697 Will be interesting to see what the responses will be

KeithSloan Wrote:
-------------------------------------------------------
> Okay I have done some digging and have added the
> following append to the FreeCAD developer forum
> [url=https://sourceforge.net/apps/phpbb/free-cad/v
> iewtopic.php?f=10&t=4697]https://sourceforge.net/a
> pps/phpbb/free-cad/viewtopic.php?f=10&t=4697[/url]
> Will be interesting to see what the responses will
> be

This is probably off-topic but I am sure many Mendel90 users will, at some time, use both FreeCAD and OpenSCAD so some level of interoperability will be welcomed.

It would be good if the GCAL library could be LGPL licensed (it always makes sense to put libraries under this license for this precise type of scenario) but I do not think all is lost if this is not possible.

If your ImportCSG functionality is written as a plugin then it is, in a sense, standalone and it might be possible to include this functionality as a non-free or tainted package. Most GNU/Linux distributions have repositories for non-free software and you could include compile-time logic to build either a free (non Hull-supporting) or non-free (Hull-supporting) variant. Distributions could then accommodate both.

I am sure that the FreeCAD team can find some way around this problem and please do not "throw in the towel" yet!

Regards,
Neil Darlow

If you have been following the discussion in the FreeCAD forum.

You will see that there is a license conflict between Open Cascade that FreeCAD uses and GCAL as used by OpenSCAD for the hull operation..

The other problem is that a Hull operation would produce a polygon, which if it was extruded would create a Mesh.
In which case would you be any worse off than with an imported STL file which would be a Mesh of triangles. How would you then use it in a 3D CAD program.

hull() and minkoswki() also work in 3D where they result in polyhedra.

OpenScad works with polyhedra so you would get a different result if you interpret cylinders, etc, as true cylinders because that is not what they are in OpenScad.

---

[www.hydraraptor.blogspot.com]

Anyways, back to the topic, my guy just went berserk with this and does not want to deal with IT geekess of programmatic drawing and "open source" (he is a mechanical engineer after all, all he wants is wants to help me to customize my mendel and also redesign it to make it bigger) so he is now all rage drawing to the last nut into Inventor and found some discrepancies between parts, Nop, i'd appreciate if you could help us with some questions i'll post in the coming days here.

After the inventor thing is done I'll post it in the Wiki, i think will be a great addition.

On the other side, all this opensource hardware thingie, what's the point of working with obscure formats that cannot be used by people of the trade as my pal to easily customize? This is like releasing a full source code because it's "open source" but only in binary format, which require a lot of work to make it work. And i'm talking about the printed parts with their useless from an engineering standpoint STL format and the lack of support of openScad.

Quote
GAZ082
This is like releasing a full source code because it's "open source" but only in binary format, which require a lot of work to make it work. And i'm talking about the printed parts with their useless from an engineering standpoint STL format and the lack of support of openScad

I can't think of an example of "open source" that ever referred to binary files only. Doesn't that defeat the point of it being "source"?

I can see the point of releasing stuff in OpenSCAD from a RepRap point of view because all RepRap software I've seen works with STLs, which OpenSCAD produces very well. From these it is very easy for a RepRap to print its own parts, the fundamental principle behind RepRap.

OpenSCAD also allows me to parametrically define models to be scalable (the Mendel90 source is beautiful in that respect, because I can for example, change the M6 lead screws to M8 in a few lines and have the entire model re-render accurately to use the new screws) and therefore to be able to extend my printer upwards/outwards using only the tools I already own - i.e., my printer. All the models I've designed that require precision (for fasteners, etc) have been written in OpenSCAD and I find this tool to be perfect for the job. I have a software development background though so thinking in code is inherently more intuitive than modeling visually.

Asking for the models to be usable by a completely different process is like saying that you gave me java code when I need to use visual basic, or that I can't manufacture a car on my vacuum cleaner production line...

If you do manage to get models transferred accurately into Freecad and output in a format that your engineering buddy can use then I'm sure it will be a well-rewarded exercise but for those of us only need to slice and print on current generation 3D printers, it's hard to understand the vitriol.

It is an opensource design and the source files are the OpenScad. not the STLs which are only on Github for convenience. If you want to make it bigger all you need to do is change the config file and it will generate all the STL files and DXF files to match.

If you look at all the Opensource projects in the world 99% are written in some programming language or other. Just because your mechanical engineer is not a programmer doesn't mean they are not source code, of course they are.

If it is converted into an a closed source format like Inventor then that is binary as far as I am concerned. It will just be a snap shot as well as there is no automatic process to convert OpenScad into Inventor so as soon as I change it it is out of date and if you change the inventor version there is no way to get that back into OpenScad.

---

[www.hydraraptor.blogspot.com]

GAZ082 Wrote:
-------------------------------------------------------
> Anyways, back to the topic, my guy just went
> berserk with this and does not want to deal with
> IT geekess of programmatic drawing and "open
> source" (he is a mechanical engineer after all,
> all he wants is wants to help me to customize my
> mendel and also redesign it to make it bigger) so
> he is now all rage drawing to the last nut into
> Inventor and found some discrepancies between
> parts, Nop, i'd appreciate if you could help us
> with some questions i'll post in the coming days
> here.
>
> After the inventor thing is done I'll post it in
> the Wiki, i think will be a great addition.
>
> On the other side, all this opensource hardware
> thingie, what's the point of working with obscure
> formats that cannot be used by people of the trade
> as my pal to easily customize? This is like
> releasing a full source code because it's "open
> source" but only in binary format, which require a
> lot of work to make it work. And i'm talking about
> the printed parts with their useless from an
> engineering standpoint STL format and the lack of
> support of openScad.

Well you could take the individual scad file for Mendel90 load into FreeCAD and then export to a format
that Autodesk Inventor understands. Okay this will not work with file that use the unsupported Hull but
hopefully it would not be all of them.

This means your Guy would only need to redraw the files that fail rather than all.

I don't know if Autodesk Inventor has facilities that would let you import an STL and then create a 3D
design using the STL as a guide.

If you try to do it with the scad file that defines a complete Mendel90 that would not work.

At least in Inventor 2013, you can import a .stl file, but you can not do anything to the model. You can not get dimensions from it either.

Can someone send me a picture of how the nuts in the threaded rod are fixed in the z axis carriage? We do not see in the vids how the nuts are fit or if they already come inserted in the printed parts.

Regarding the OS thing, yes, working in OpenSCAD is truly working with "source" and not explicit designs as in Inventor, Solidwords or any other CAD software.

The thing my pal annoys the shit of him is that the STL printed parts are faces, they do not work in Inventor for example, when aligning holes and stuff. That's why he is taking the job to redraw them using an imported STL as base.

Thanks guys.

You don't need to get dimensions or open it in another CAD system. The model and the scripts with it produce the CAM files to make the machine from the configuration file using only free opensource multi-platform programs. The BOM lists the sheet sizes, rod lengths, etc. Openscad shows the bounding box of the machine in an echo statement.

There are plenty of programs that will give the bounding box and volume of the STL files, which is all you need to know to 3D print them. Similarly if you cut the sheets by CNC the CAM program will show the bounds of the DXFs. If you want to make them by hand it produces PDF templates with cross hairs. Why do you need any other dimensions? I don't and I have made hundreds of them.

---

[www.hydraraptor.blogspot.com]

Regarding the nut traps, see my latest blog post.

---

[www.hydraraptor.blogspot.com]

I'm late to the party, but I had the urge to chime in.

You OpenSCAD aficionados need to understand that engineering and design types are the complete opposite of programmers: modeling visually is inherently more intuitive than thinking in code. From what I understand GAZ082 and his friend wanted to make mods on the design, and for that they need to have a model that they can interact with, in a GUI.

OpenSCAD is only used by a very tiny niche of users, RepRappers. Engineers, designers, architects would never work with such a thing. This is simply unfathomable, because the design process is highly visual.

Last summer I pulled the Mendel90 source and managed to generate the assembly in OpenSCAD, because I wanted to study it. I have a MendelMax 1.5-based printer that I wanted to make mods on, and was looking for inspiration. But there was nothing I could do in OpenSCAD apart from zooming and spinning the model. Trying to analyze endless lines of code that amount to gibberish to me is frustrating and I quickly abandoned it.

Which is why I'm grateful for KeinthSloan's efforts to attempt to bridge the gap between OpenSCAD and FreeCAD, or in other words the rest of the world. (I've been able to import most Prusa i3 scad files as solid parts in FreeCAD)

GAZ082, it would be great if your colleague would share his model once he's done. STEP is a universal exchange format that most CAD programs can import.

Autodesk Instructor here... Inventor professional evangelist I have heard good things about Autodesk Inventor Fusion? Its installed alongside your Inventor install if you have at least version 2012. Its built for exactly this reason... its a half way house for Inventor users that need to exchange formats with other CAD packages and does allow some basic manipulation of the model without parametric data i.e. placing new holes in patterns or changing the solids basic dimensions.

Hope it helps

@ setherith

Are you saying that Autodesk Inventor Fusion can alter a .STL file?

I'm not 100% I don't have it installed on my home computer but I'm sure I've done it from my work machine. I'll need to check. I don't really know a lot about Fusion, but I have heard good stuff about it. Worth a try if you have it installed already

They can't made mods to the design unless they learn OpenScad. If it is done in any other package it cannot be merged back into the GitHub source so will never become part of the official design.

When I showed OpenScad and what I could do with it to the senior mechanical engineer where I used to work he was fearful for his job in the future because be could see how much more powerful it was compared to conventional CAD.

In the same way that electronic logic design done by drawing schematic diagrams has been complete replaced with VHDL / Verilog, etc, eventually all design will be done by computer scripting languages.

---

[www.hydraraptor.blogspot.com]

@nophead: I think the subtlety of your parametric design is somehow being lost on the original poster.

Why spend hundreds of man-hours importing the design into a CAD environment to make dimensional changes when (by installing Python, OpenSCAD and Inkscape) you can customize the complete design by running a Python script.

I would certainly do that and invest some extra time into learning OpenSCAD to make any final, trivial, customizations.

Regards,
Neil Darlow

---

I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.

Quote
nophead
They can't made mods to the design unless they learn OpenScad. If it is done in any other package it cannot be merged back into the GitHub source so will never become part of the official design.

I don't know about the OP and his friend, but simply checking out and studying an assembly does not require merging back to GitHub source. It does require some real CAD software though!

How do you measure clearance from one part to another in OpenSCAD?

Quote
nophead
When I showed OpenScad and what I could do with it to the senior mechanical engineer where I used to work he was fearful for his job in the future because be could see how much more powerful it was compared to conventional CAD.

LOL that is so ludicrous. So you think OpenSCAD invented parametrics? The first CAD software to do so was Pro|Engineer in the late eighties. And it was GUI-based. I've been working with one parametric CAD package or the other since 1998. Assembly configurations and table-driven assemblies can accomplish the same thing as what your configuration script does - through a GUI.

Another thing: OpenSCAD is CSG-based, which is a thing of the past. For two decades most CAD software have been based on boundary representation (B-rep) which allows much more complex models. Do you seriously think a car or an aeroplane could be designed in something like OpenSCAD or any other scripting program?

In almost all but the simpler scad parts I've looked at, there were errors. Joined or intersected primitives which did not exactly match. It may not matter to produce STLs, but most would be invalid for manufacturing.

Quote
nophead
eventually all design will be done by computer scripting languages.

You are a respected RepRap designer, and I'm amazed you could create your designs in OpenSCAD, but really, this statement is unfounded and unrealistic.

Quote

I don't know about the OP and his friend, but simply checking out and studying an assembly does not require merging back to GitHub source. It does require some real CAD software though!

You can view complete assemblies either exploded or not in OpenScad from any position, angle or zoom. No need for another package.

Quote

How do you measure clearance from one part to another in OpenSCAD?

You don't measure anything in OpenScad, you tell it how far apart things should be.

Quote

LOL that is so ludicrous. So you think OpenSCAD invented parametrics? The first CAD software to do so was Pro|Engineer in the late eighties. And it was GUI-based. I've been working with one parametric CAD package or the other since 1998. Assembly configurations and table-driven assemblies can accomplish the same thing as what your configuration script does - through a GUI.

Might be ludicrous but it is true and he is a long time Pro Engineer user. Of course I know other CAD packages can do parametrics but OpenScad is entirely parametric. Scripts are always more powerful than anything a GUI can do.

Quote

Do you seriously think a car or an aeroplane could be designed in something like OpenSCAD or any other scripting program?

Yes of course it can. Humans and all other living things are generated by a script with only four symbols.

Quote

In almost all but the simpler scad parts I've looked at, there were errors. Joined or intersected primitives which did not exactly match. It may not matter to produce STLs, but most would be invalid for manufacturing.

Yes that is deliberate because CSG operations on coincident faces fail. It is essential to create manifold STLs and those are used for manufacturing. I manufacture these machines using those files.

---

[www.hydraraptor.blogspot.com]

Quote
nophead
Yes of course it can.

So you believe this kind of body shape can be scripted, and I mean designed by scripting lines of code rather than creating the underlying NURBS geometry with visual and real-time input? Come on. You programmer types think that everything can be coded.

Quote
nophead
Yes that is deliberate because CSG operations on coincident faces fail.

That's not what I'm talking about. Here's an example: a cylinder is cut and joined on its flat face to a cube, only the planar face of the cut cylinder exceed the cube by a minute amount, which creates a tiny sharp edge that would cause problem if you were to machine a mold. Or the other way around, the cube is wider than the cut cylinder. This is not deliberate, this is a calculating error that would never happen in a real CAD program because you would not work in CSG, but draw a correct profile and extrude it. Knowing your attention to detail I would probably have a hard time finding such errors in your own scad files, but I tell you I've seen those errors quite often. The CSG method is archaic.

Quote
nophead
You don't measure anything in OpenScad, you tell it how far apart things should be.

I'll repeat a second time: for someone who wants to analyze an EXISTING DESIGN such as yours, not design a new one, how would one measure the clearance between one component and another in your OpenSCAD assembly?

NormandC Wrote:
-------------------------------------------------------
>

Quote
nophead
> Yes of course it can.
>

>
> So you believe
> [url=http://en.wikipedia.org/wiki/File:Ferrari_458
> _Italia_--_05-18-2011.jpg]this kind of body
> shape[/url] can be scripted, and I mean
> [i]designed[/i] by scripting lines of code rather
> than creating the underlying NURBS geometry with
> visual and real-time input? Come on. You
> programmer types think that everything can be
> coded.

Yes I believe everything can be coded. It is NURBS code that draws the car. Those routines could be called by a script, they don't have to be called from a GUI.

>
> [quote=nophead]
> [size=medium]Yes that is deliberate because CSG
> operations on coincident faces fail.[/size]
> [/quote]
>
> That's not what I'm talking about. Here's an
> example: a cylinder is cut and joined on its flat
> face to a cube, only the planar face of the cut
> cylinder exceed the cube by a minute amount, which
> creates a tiny sharp edge that would cause problem
> if you were to machine a mold. Or the other way
> around, the cube is wider than the cut cylinder.
> This is not deliberate, this is a calculating
> error that would never happen in a real CAD
> program because you would not work in CSG, but
> draw a correct profile and extrude it. Knowing
> your attention to detail I would probably have a
> hard time finding such errors in your own scad
> files, but I tell you I've seen those errors quite
> often. The CSG method is archaic.

I can't see any example but I repeat: they are deliberate. You will find a constant eta = 0.01 which is used to offset coincident faces all over the place due to the limitations of CSG. Without it CSG becomes ambiguous. Try setting eta to 0 in the config file.

I agrees it is a PITA but there is no reason why it can't be fixed by changing OpenScad to use a different internal representation. Also it is of no consequence because the parts are designed to be 3D printed. There are much more obvious reasons why a lot of them can't be moulded.

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[url]http://www.hydraraptor.blogspot.com[/url]

NormandC Wrote:
-------------------------------------------------------
>

Quote
nophead
> You don't measure anything in
> OpenScad, you tell it how far apart things should
> be.
>

>
> I'll repeat a second time: for someone who wants
> to analyze an EXISTING DESIGN such as yours, not
> design a new one, how would one measure the
> clearance between one component and another in
> your OpenSCAD assembly?

You would write an expression to calculate it and echo that. For example, suppose you wanted to know how much clearance there was between the bottom of the Y carriage and the top of the Y motor bracket. You would have to look at the code that makes the Y motor bracket and see its height is represented by a function y_motor_bracket_height(). Also the code that draws the Y carriage places it at Y_carriage_height. So the gap between them can then be displayed with:

echo(Y_carriage_height - sheet_thickness(Y_carriage) / 2 - y_motor_bracket_height());

Which will print 2. However I don't see why anybody would need to know that. If it is important it has some clearance, which is it then that is expressed in the code. This is the line that determines the clearance.

Y_carriage_height = y_motor_bracket_height() + X_carriage_clearance + sheet_thickness(Y_carriage) / 2;

So there is no need to measure anything. With OpenScad you tell it the important dimensions and it works out all the others. I have never needed to know what the actual value of Y_carriage_height is, for example. I just specified it should have 2mm clearance. I don't see why anybody else needs to know either.

If you added some obstacle under the carriage that might need additional clearance you might change the code to:

Y_carriage_height = max(y_motor_bracket_height(), my_widget_height()) + X_carriage_clearance + sheet_thickness(Y_carriage) / 2;

The machine can be made from scratch materials using the files the design creates. It tells you what size sheets you need to cut, how long the belts should be, etc. It also echos the total size of the machine. What else do you need to know?

There are thousands of implicit dimensions, for example how far apart are the ribs on the Z brackets? I don't know or care because I can see they look appropriate and my printer makes them from the STL. If I really wanted to know I could add an echo statement or I could measure it in NetFabb studio.

---

[www.hydraraptor.blogspot.com]

Quote
NormandC
for someone who wants to analyze an EXISTING DESIGN such as yours, not design a new one, how would one measure the clearance between one component and another in your OpenSCAD assembly?

How would you do it on that beautiful Ferrari 458?

nophead, you keep thinking design (not CAD modeling, DESIGN) can be done by scripting, and I'm telling you it would hamper the creative process which due to the human brain of a majority of the population, sees and touches things rather than make some mathematical abstraction. Styling of a Ferrari will never be done by programming, it is utter nonsense. When it happens, the human race will have turned into robots.

Quote
nophead
So there is no need to measure anything. With OpenScad you tell it the important dimensions and it works out all the others. I have never needed to know what the actual value of Y_carriage_height is, for example. I just specified it should have 2mm clearance. I don't see why anybody else needs to know either.

I keep repeating it: to analyze and understand your design without needing to deal with a console. Why is it so hard for you to comprehend? Programmers are a minority of the population. Our brains do not work the same way as yours, obviously. I find OpenSCAD's value unfathomable.

@ QuackingPlums

I have not worked on such complex surfaces as car bodies, nor with high-end parametric programs like CATIA or NX. But even in mid-range packages there are measurement tools available to get for example the minimum distance between two surfaces, or normal distance, etc. On non-uniform surfaces, you could create a plane and then an intersect curve between the body and the plane. Certainly you would not need to enter any mathematical equations.