algorithmic modeling for Rhino

Hi there

PROBLEM I AM TRYING TO SOLVE :  I am seeking for a component that allow me extracting curves directly from a jpeg image .

the image I need to extract curves from has totally white background and all contour i need to extract are black-well defined curves.

Does anyone know if  there is a component that allow user to extract the curves automatically .

The idea is then to clean/ process these curves in GH to generate a final path of the original image to be used for CNC purposes.

thanks in advance


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This is called 'tracing'. Grasshopper doesn't provide such a component by itself, but one of the plugins may well. Can you post an example of such an image?


David Rutten

Good morning David and sorry for late reply .

I could put my hands on the kind of image we are trying to convert to DXF only today and some of the things I was told are wrong.

I wrongly reported the image was white background black trace which is wrong.

attached please find a sample of the kind of image we are trying to trace

what we want to extrapolate is only the external silhouette , we don't care about other inner references

if you can suggest some tool to quickly and precisely convert it to DXF we really appreciate .

thanks , regards .


I would trace over the image in Rhino using curve - interpolate points (and straight lines where appropriate)

Then scale the lines to the desired size, join, and export to dxf. Just don't try to go around a sharp corner with interpolate - stop and start a new line.


do you mean there is already a function in rhino for image tracing? or you mean to do it manually by importing the image on the background?

we need to automate this procedure , we have to trace several images every day so we need a plugin/component to do it for the operator thus reducing time and improving precision if compared to manual procedure


He meant manually. I'm not sure how to automate it, pixel algorithms aren't my forte.


David Rutten

Hi David and thanks for clarifying

I wonder if import PDF function available on rhino 5 does have something in common with what I am looking for. I am not either expert on this

i used this function a few times  ( it actually works only vectorial pdf ) but I gotta say it works very well and it's very precise




With Millipede you can create an approximation that is not bad at all...The problems that you could have with this solution are the same that with other professional tools (like Illustrator...): the image quality and how you process the image to get what you want.

To use millipede you have to create a mesh with the same number of points that you want to evaluate (in other words, the number of points that you analyse in your image should be the same that the number of points in the mesh). With the saturation values for that points you just need to create a mesh Isocurve component and attach everything. The slider attached let you select where do you want the isocurve cut in the saturation values.


Many Thanks Angel :)  , this component looks like what I am looking for.

I am gonna try it right now.



Hi Dear Angel


I have installed the millipede component and I am quite impressed about the amount of components available in to this plugin , it’s a thick manual !!


 I tried to recreate your definition  it but I am not able to get it to works fine cause I don't know some of the components and how to use and correctly set them

could You kindly share your definition ? I’d really appreciate


Many thanks








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