Importing polygonal shapes and redefine them

Hey guys,

I am a beginner in working with rhino and I hope to get some help. I sure there is a simple solution for my question!

I want to know how to create smooth shapes for holes and pins like on this lego peace.

You can see it on the pic I’ve found on the internet: on the right: just after the import/ on the left: changed parameter settings.

So, are there any settings I have to make when I import a brick?

Or do I have to change the parameters after the import? How does it works?

Could anyone help me in this case?

Thanks you very much!


after importing your mesh, try the command _Weld eg. with an angle setting of 20 or higher. Check out the helpfile for _Weld und _Unweld too.


Rhino doesn’t have any tools to automatically add details to a mesh in places where the mesh doesn’t have detail. This is not just a question of changing some parameters. (going the other way - from the left shape to something like the right (disregarding the part that sticks up) - is simpler).

I am guessing but it would appear that you want to get a smooth NURBS object out of a rough mesh model. That process is called reverse engineering and is a very difficult process. There are a few plug-ins available to help you (check the resources page) but they tend to be expensive. There is also an informative document available on the Rhino wiki.

Success at Reverse Engineering, ie going from a mesh to smooth NURBS surfaces, is much more likely if the user knows how to create geometry starting from “scratch” with similar shapes and arrangement.