Full Version: stl import converters?

Greetings,

I've seen from some really old threads that stl isn't likely be added to the import formats. I have a 3D scanner on the way that only outputs stl, ply, and obj. None of those appear to be directly imported by MOI. Can someone recommend a converter (online or Windows) that does a good job of converting those formats to something MOI can import? A search comes up with plenty of options, but I have to wonder if some work better than others to get the most information into MOI.

Thanks,
Rusty (please don't make me try to learn Fusion again)

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<< that only outputs stl, ply, and obj.

Moi can import directly OBJ format! ;)
But many more better if model is in "quads" but not too many like here! :)

First method by native Moi Function : SubDivision / Create from FIle
Second method by Script _ Import OBJ

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Thanks I see the SubD option. Funny that I've never opened that menu before. I'm not familiar with the script though.

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Hi Rusty, that's not good advice from Pilou (sorry Pilou).

Fundamentally the point cloud data collected by a 3D scanner is not suitable for direct conversion into CAD surfaces and solids.

It's a specialized and difficult process to go from a point cloud to a CAD model.
It's an area of work called "Reverse Engineering", some previous discussion here:

http://moi3d.com/forum/index.php?webtag=MOI&msg=11360.4

It's not a matter of just formatting the data differently, the scanner generates a big set of points. Those can be formed into a huge mass of triangles which is what you'll have in the .stl , .ply, or .obj outputs.

You can bring a big bunch of triangles into a polygon mesh editing program (like Blender, Cinema4D, 3DS Max, etc...) but it's very different from the structured accurate surfaces that is used for CAD programs like MOI.

So it is a difficult problem and it is not likely that there is just a "push a button" type method to do it other than making very poor quality CAD data with just every triangle as a trimmed plane. That isn't what CAD programs are designed to work on.

The main advice is "don't do that".

- Michael

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And the SubD converter is not suitable for this either. The output from a scanner is triangulated point cloud data, it isn't sub-d "all quads with edge flows" type data.

- Michael

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Also some info on this in the FAQ here.

- Michael

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Hi Michael,

Thanks for depressing me so quickly :-) I'll look through the links you posted, but I can't say I'm real surprised to hear what a bad idea this is. From the videos I've seen, they seem to used the rough blob of a scan to make a real drawing in CAD. I know going in that the biggest problem would be after the scan.

Thanks,
Rusty

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Hi Rusty, if you need to get just a few reference points like you know something is a circle and you want to draw a circle in MOI there, you can use this OBJ to 3DM Wireframe converter:
https://moi3d.com/wiki/Resources#Obj23dmWireframe_converter

That will bring in the triangle mesh model as wireframe lines in MOI and you can snap to them.

re:
> From the videos I've seen, they seem to used the rough blob of a scan to make a real drawing in CAD.

Yes, there is some software that is specialized to do this task of "Reverse engineering". But good ones can be in the $10,000 range and still have a high learning curve.

The feasibility does depend on things like what type of objects you need to process. If they're mechanical shapes and you want to extract a few lines and circles that could be possible but if it's a complex organic non-mechanical shape that's much different territory.

- Michael

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Michael,

I downloaded that wireframe tool from the FAQ link earlier. I don't actually have the scanner yet, so any experimentation will be later this week I imagine. One primary thing I want to do "should" be relatively easy. There are a number of welded steel fuselages for small aircraft that I'd like to be able to build from scratch. The problem is that the kit manufacturers never released any fuselage drawings to allow people to build their own. I'm hoping to be able to scan a welded tube frame and at the very least get dimensions from it. When I get to that point, it will be a new thread for sure.

Thanks,
Rusty

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Hey Rusty,
What you want is a “Faro Arm”.

With the scanner you are trying to build your surface and get a visual representation.

With the Faro Arm, you will Aquire points and dims to use in your CAD package to actually BUILD the data….

Just my 2 cents

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The only price I saw on that "Faro Arm" was $16k, so not quite hobby level pricing. I'll have to make due with a scanner.
Rusty

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“”””””” Yes, there is some software that is specialized to do this task of "Reverse engineering". But good ones can be in the $10,000 range and still have a high learning curve.”””””””

Yeah…. I use a Mitutoyo and my head..

But my explanation is still valid. The scanner is not for CAD.

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I'm not sure if this helps or not... I have done quite a few scan to cad models. there is a step that need to be done before you get it into a CAD program. I would be sent the scanned model (they are very heavy) I would bring them into Blender and hand retopolize them with as low a poly count as I can get (the models were usually bottles with threads, I wouldn't do the threads in blender) I would use shrinkwrap and sub-d as an aid. Once that portion was done (all quads) I could bring them into Moi and create threads or what ever needed to be precise. It was a pretty quick activity once one got going.
cheers,
Val

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Thanks for the tips. I've seen others recommend Blender as an intermediate step as well. It does sound like the initial point cloud data is huge, and reducing that size would certainly make it less painful to work with. I fear I'll have a lot to learn once I start playing with the scanner.
Rusty

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Wings3D supports importing STL. PLY and OBJ and Wings3D is FREE.

Blender3D is also FREE and supports STL, PLY and OBJ as well.

https://www.wings3d.com/

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You could also import your OBJ into Blender and then use the excellent Blender to Moi Addon which must be installed on both Blender and Moi3D. I've used it and it works fine.

Here is a thread on this must have plugin

https://moi3d.com/forum/index.php?webtag=MOI

Sorry but the above link does not seem to work. I am uncertain how you post a link to a thread here. I do not have this issue on other forums, so I posted a remark in the thread to make it current.

I hope that helps.

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Hi Kenmo,

To grab the link to a posting or thread, use the link at the upper right corner, the one with the thread & article numbers.

Here's the thread you were referencing: https://moi3d.com/forum/index.php?webtag=MOI&msg=11634.1

--Larry

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Thanks for links and suggestions. I'm still learning the basics of the scanner right now, but I'll take a look at the import options again when I have something useful to import.

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