Best practice for importing and exporting curves to and from Blender

What is currently the best practice to do a round trip with curves from Rhino to Blender and back?
I have read that this can be achieved through OBJ (albeit hacky, apparently), but this requires exporting a mesh as well.
Blender’s DXF exporter doesn’t seem to support curves at this point in time…
There’s no info on curves support for FBX in the docs, so I would have to test to see.

Not yet perfect but import_3dm has some preliminary support

May I quickly ask: are there any limits to what Blender curves can do compared to Rhino? Are they ‘real’ NURBS, so round-tripping won’t ‘shave off’ any data?
I always found good curve tools important in my workflow, and I’m under the impression Blender doesn’t really shine here (yet).

Thanks Nathan, I have made the decision to only go from Rhino/ GH to Blender and not the other way around. And DXF import also supports curves as last resort.
I was investigating to what extent I could use Geometry nodes (Blender’s Grasshopper) to offset and fillet curves, but there’s no proper offset modifier/ node. So that ends up being a dead end for now. But, I do like to have the curves for Scattering geometry with Scatter 5.1.

@Eugen Blender’s curves are not double precision, so this does definitely shave off some precision. But for the work I am doing that shouldn’t matter much. This is also the case with 3ds Max though (as to not discredit Blender too much :wink: ).
Recently, there was the introduction of the Curve Pen tool, which brings a workflow closer to that of Illustrator to Blender. It is a shame though that there aren’t more modifiers for the procedural workflow I was envisioning.

As said, the current implementation is the first iteration and lacks (as can be seen in the screenshot), but hopefully can help getting bootstrapped with curve work in Blender.

The other way around doesn’t exist yet at all, but the Blender exporter to 3dm is still on my mind. And who knows, with the CPython integration in Rhino 8 it actually makes sense to directly use Blender as a Python module and get the integration that way.

1 Like

@nathanletwory You’ve likely explained it many times already… [and I’ve done it in the past, and yet I can’t figure it out now] In the import there are many things…
Screen Shot 2022-05-15 at 17.10.05

confusing to understand which part to install [blender won’t take the whole zip or the folder…?

that imports the 3dm structure but no geometry is visible…
Please kindly link to the place in the forum where you explain all this.

thanks a lot

Please check the Installation section of the README:

1 Like