Convert (figurine) to mechanical CAD format

Hello.
I am in a bit of a tricky situation and am not sure there is a straight-forward option here…
I have a model file of a character figure and need to convert that to a CAD file format so that I can make edits with it and using it as a tool (such as use it to subtract from other shapes, make cuts, etc.).
The only question… how do I do that? My CAD application supports all the common (neutral) formats, but I have a FBX file… which is of course not supported. I was thinking I could convert it via Blender… but that does not write to any of the CAD formats that my tool uses.

Help Please?

Thanks,
J

Hey!

While exporting CAD models as meshes is pretty straightforward, the other way around is not that trivial unfortunately.

Using Blender you could try to export as DXF and work with that format (and probably convert to any other cad based format you desire): https://all3dp.com/2/stl-to-dwg-how-to-convert-stl-files-to-dwg-autocad/

If you happen to have access to AutoCAD you yould also try the Convert Mesh tool:

Thanks. I tried the DXF option, but that just turns it into a file that is far too big and with simpler files I don’t seem to get anything usable out of that.
AutoCAD… not sure, I don’t like their products and they are way overpriced IMHO. I will take another look though…

Hi,
I had a somewhat similar issue not too long ago. In my case it had to do with machining a mold from a (cartoon) face within a predefined block of material (and all the usual pins, gate, etc. features). So the only way was to import an organic shape into a geometric/mechanical environment… not pretty.

BUT, over on the GrabCAD site (question does not seem to be available anymore), I asked a very similar question and got the following responses:

  • use NETFABB (or Geomagic Design X)
  • into 3dStudio, then SAT, then Inventor, then STEP…
  • use InStep Studio 3D

I tried out the different tools and the Geomagic tool is by far the most advanced (read: complicated) but also most expensive (I saw $20k !!!). Netfabb is very good, but expensive ($4.6k/yr as of this writing - don’t get me started on these annual-only license packages). The Inventor route wasn’t an option (again, cost). The last one is the one I ended up using.
InStep Studio (used to be just InStep, the InStep Studio, now InStep Studio 3d… go figure) is low cost (I got a 30% off discount shortly after signing up for the 10-day trial, you might be able to just ask for a discount) at $175 (that is for a permanent license!) and does a number of things (have yet to figure out some of them) but one thing that worked well for me was the conversion to a smooth (NURB?) surface body that is far more efficient than using the full triangle collection (and works better in my CAD application too when it comes to cuts/bools). I did need to go through the tutorials to figure out some of the detail settings, but that tool all of about 10min… You can probabably google it, but this is the (new) direct link (today, anyway): https://instepstudio3d.com
If you can post the model you are using/trying to use, I would be happy to take a quick look and let you know what I can see/do…
Best,
JP

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I had a similar situation where the client has a dynamically generated mold as a mesh-file and needed this converted to STP. I used Freecad (https://www.freecadweb.org/) for that conversion. The resulting STP file isn’t pretty, but it works.
Here’s part of the pdf manual I’ve written for the client:
mesh to cad.zip (339.6 KB)

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Hi,

If you got Rhino, you can do a MESHtoNURB command then export the result in many format like STEP, IGES… I do that all the time, It may sometimes generate issues but most of the time it works !!

Thanks. I did a quick review of the mesh-to-nurbs option in Rhino (I don’t have it, but could maybe consider it) and it states that

“MeshToNurb will convert a (faceted) mesh structure to a (faceted) NURBS structure.”

However, this would presumably just make the file bigger/heavier (or whatever)? I tried the FreeCAD option which seems to use something similar, and the output was gigantic… and not usable. Am I misinterpreting the conversion process?

Thanks. A lot of info there…
Could you take a look at this file and let me know what you think?
https://skfb.ly/6QXuw
Only need the head (not the collar).
Cheers

Sure!
This one is actually quite straight forward. Like I said, I use InStep Studio 3D for this one as I think it has some great tools for this kind of process (not that others don’t - just that this one worked for my budget).
Here are the steps (the attached zip has images of each step):
BABY_YODA_MESH.zip (6.0 MB)

  1. Import the file
  2. Split the bodies (it should ask to do that)
  3. Auto-Repair the eye sockets (those are separate parts), use the Hole tool to automatically stich the openings (also for the neck).
  4. Generate a Surface using the RevEng Nurbs tool.
  5. Export to STEP

Just to see, I tried two different resolutions for the NURBS tool, one with the default setting (6k faces) and one with a coarser setting of about 2k faces. The smaller file is included in the attachment and resulted in a file of about 14Mb. The more detailed model is somewhere around 40Mb (and would be the one I would use for work), but it is easy to define the resolution yourself and quite quick to get a preview…
Note that you would need to import one file at a time and use them that way, but that should be fairly trivial. Depending on complexity of the part, there might be issues that need to be resolved differently, but I am still learning this…
Hope this helps!
P.S. I apologize if I am ‘advertising’ one package here over a (more?) general workflow, I know that is frowned upon, but this has worked well for me (and, I think, can help for these cases).

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Thanks for the suggestion and for the handy guide. I did give FreeCAD a try…
The file I am trying to convert is this one:
https://skfb.ly/6QXuw (just the main head section though)
When I run this through FreeCAD, it takes a long (LONG!) time (actually, still waiting for it to complete, it did partially freeze my computer) and I must admit it took me a few minutes to figure out where to go in FC… but I guess you get what you pay for :wink:
From your explanation, is this just a triangle to triangle converter or does/can it apply some kind of reverse engineering to the data?

Indeed, there’s no clever reverse engineering. Just triangle by triangle.

Thanks for the information. I think that is the issue… it did crash in the end without any useful output. I’ll give it another try later.

Awesome! Thanks so much for doing that.
I will need to digest this a bit and play with the file you sent. Will check back later.

I wanted to close the loop on this…
@saphires, @primofan, @klaasnienhuis, @3dmdesign : thank you all so much for your insights and helpful information, it helped me learn what I had to and get an idea of the landscape of available tools.
In the end the converted file provided by primofan was close to what I was looking for and I decided to try the instep studio 3d application as they offer a free trial (still figuring out the details, but the tutorials are moving me along). I did manage to follow the steps mentioned and got a good output, but want to know more about it and perhaps fine tune it further for this task.

Again, thank you all for your willingness to help me.

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I forgot, but there is the very powerful but also very expensive PowerSurfacing tool, a plugin for Solidworks, which is very nice to use and has manual and automatic reverse engineering functions.
It is very efficient, but also very expensive.