Model this in Rhino

I downloaded this mesh cloud form as an obj file. How do you model a cloud form like this with nurbs in Rhino?

@Woodee try revolve with desired number of control points on curve and select deformable during command :wink:

You can probably start with a few ellipsoids rebuilt with a certain number of control points (not too many) to make them easily deformable, then start pushing them around plus using standard transformation tools such as scaling 1/2/3D, you’ll end up with a similar shape. You can then BooleanUnion the ellipsoids together to make one object.

Then the fun begins, if you want smooth blends between the ellipsoids, you will need to fillet/blend the inside sharp corners formed by the BooleanUnion, that will be most of the work…

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Sorry but could you explain some more as I don’t understand what shape revolve would create. Revolve would give me a symmetrical shape and the cloud is asymmetrical.

How do I create a smooth transition between two spheres?

Hello - in this case FilletSrf


Fillet surfaces but poly surface is open and wont Boolean.

You need to use join command for connecting surfaces.

or, you can booleanunion the two shperes first then use filletedge

@Woodee - to replicate this shape as close as possible i would try to create 8 - 16 section curves then rebuild them to match cp and loft them or even sweep along perp section of this cloud. I believe this would be the quickest way here and will be based on one fluid surface ready for tweeking without complicated blends.

If this is not the case as i mentioned earlier i would try with revolved curve with deform on and then i would rebuild it for finner tweeking.

If you have to design “desired” cloud i would go to blender and i would use metaballs to prototype cloud and then i would use first approach mentioned in this post.

cloud.3dm (102.6 KB)
Yes filleted and blending only works for simple forms in this case.
I have tried the section curves and then loft. That gave me an open surface but not as rounded as in the original.
Difficult to keep the forms rounded when tweeking a surface. I have attached file with mesh for you to look at.

Perhaps a Grasshopper definition so you could monkey with the sphere and ellipsoid sizes and locations, without destroying the blends between them.

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Thanks John but I have been trying to do this within Rhino since V2. Seems like the one thing I am unable to do. I have been reluctant to put in the time to learn grasshopper as Rhino satisfies most of my needs.

@Woodee easy-peasy - here you are - cloud_REBUILDED.3dm (630.9 KB)

I left objects used object so you can understand earlier described process.

Create section lines of the object (16 worked well here ) rebuild them for clean iso spacing ( i’ve rebuided them to 64) do on them closed loft (here you can also limit those points i used here 32) - in you get spikes on the ends remember to make last and one before points on surface to be in one plane (best way to do it turn on srf points pick one before end use selU or selV then pick last change gumball to object and flatten desired axis same thing on other end).

If you need more acuracy rebuild with higher numbers and dont simplify loft and thats all.

Thank you D-W. Interesting way you get the sections. What command are you using to do that?
Could I generate this form from scratch in nurbs by drawing curve then using polar array create series of curves that could be adjusted then lofted? I need to give this a try.

I just made srf and polar array turned mesh into polysrf obj and used intersect two sets no big deal :wink: Yep you can draw your own crvs tweek to taste - besides you can draw few turn on history for rebuilded loft and see the results on fly :wink: @Woodee happy clouding :wink: