Working on an STL

Hey there,
is there any way to work on an STL file and merge it with an object i have build?

Greetings Paul

Here is the file:
auto print.3dm (17.7 MB)

Hi Paul -

You have converted the mesh from the STL file into a NURBS object, and so, yes, you can work with that and “merge” that with another polysurface. It looks like you’ll want to split the “old” object - and that is a bit messy. I’d create a vertical plane at the front end of the new part, explode the old object and use the vertical plane to manually trim surfaces.

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Hey wim,
That worked pretty well! Any tips with more complex polygons? I had some issues because there were alot of surfaces…


post an example and we’d be happy to help!

This one.
2017.08.02.DEWALT_DRILL_HOLDER_UNO.stl (1.6 MB)
I took it from Thingiverse and modified it since it didnt fit into our printer. I used two faces to split the middle part and take out one compartement. meshtoNURBS took veeeery long and also the mesh creating for the stl to print. Exploding and joining took some time too…
Did I make a mistake here? Is there any way to handle that much surfaces?

Thanks for the help guys!

mesh to nurbs is a very very blunt tool. what you did by running that is to take each single polygon of the file and convert it to a planar nurbs surface. this makes a polysurface that is rarely useable for anything.

the better path is to grab the wip of v8, use meshsplit or the mesh booleans to split to cut out the parts you need to remove or modify.

then from the mesh tools menu use patchsingleface to “bridge” areas of the hole you just created into manageable sections. (you can an also join two disjoint parts together this way) Then use fillmeshhole to fill in the holes you created between the bridges.

use show edges to check for naked edges and verify you are watertight.

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Thanks for the answer Kyle! Really appreciate this community :slight_smile:
Going to try this out!


PS: boatymcboatface is really cool! You motivate to stay on track with a design career :slight_smile: thanks

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I just messed with this in v8… you can use a cube to mesh boolean subtract the one pocket out, then boolean mesh the two parts back together,.

I ran into trouble trying to split them, but a high polycount quadremesh (150k)
rebuilt the mesh and the boolean split worked on that.

I used nurbs cubes as splitting objects but used the MESH booleans not the regular nurbs booleans.

I’m still a bit lightheaded at seeing a mesh boolean work in rhino 8 wip… it’s been a long time coming…

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Nice! Looks great :wink: really happy to see that the mesh tools work! Will be a great help!


“work better” IMO there is still a long way to go to say “they just work”

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