Add dimensions to organic shape (from 3D scan)

Hi all,

I’m new to Rhino and Grasshopper and I’m looking for the right program for my project.

I 3D scanned a human lower arm and saved it as an STL and edited a bit in Autodesk Meshmixer. My goal is to be able to adjust the measurements of the lower arm (length of fingers, circumference of the wrist etc.). I tried to do it in Autodesk Fusion and Autodesk Inventor but those programs don’t allow to add dimensions to organic shapes.

I would like to add dimensions to certain measurements and be able to do it with a 3D scan, is this possible in Rhinoceros combined with Grasshopper?
Or do you have to make the arm from scratch in Rhino without using a 3D scan?

Would be awesome if someone can answer these questions!

Thank you in advance!

Kind regards,

Do you get point clouds from the 3D scan?

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I dont think so but I’m not sure (just starting the 3D-scanning world), how can I check this?

It is this scanner:

I think you would need to derive sections from the scan, clean up the curves and then scale non uniformly based on the requested sizes. The resulting curves can then be lofted into a new shape.
Alternatively you could make a wireframe bone structure where you define the joint thicknesses and then skin the result. @DanielPiker has made something like that see this thread:

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Thank you so much, I’m going to check it out! Do you know if you are able to specifically ad dimensions with this method? Like say; circumference wrist = 185 mm.?

yes, this is possible. Just measure the length of the curve, define the target length and derive the scale factor from it. Example: say your scan is circumference 160 and you want it to be 185, scale factor would be 185/160:

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Hi Gijs,
That is awesome! Can you maybe explain the elements in the image a bit? What are the names of the elements you have used (or would use in this example)? And how would you use them?

I hope it’s not to much to ask.
Thank you!

Kind regards, Debora

Hi Mahan,
What part of my project rely on the point clouds structure? How do I use them?

Kind regards,

@dgeradts From some of the scanners you will get the scanned object as point clouds. There are some plugins such as Volvox that can help you to modify your model through point clouds.


@mahanmotamedi1991 How do I know if mine has point clouds? How would the file or data be called? And can I find them in any regular 3D designsoftware?

Well you saved as stl you said, so it’s not a point cloud, but probably your scanner is capable of saving just the point data, because that’s the starting point of such a scanner anyway.

If you doubleclick on the canvas, you can search for components. The ones I used:
Curve (geometry parameters)
Length (Curve Analysis)
Scale (Transform menu)
Division (Math operators)
Panel (input parameters)
Number Slider (Input parameters)

so just standard components. But it looks like you are completely fresh to gh. Best is to start here:

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Thanks a lot!!
It’s really helpfull!

Could I maybe ask you some more question through e-mail or something?