I’m modelling and old ink bottle which is cast, it’s thick on the inside and irregular… It would be really easy to model it in t-splines to get a smooth shape but it’s a pain in Rhino as I can only seem to pull the inner cube around with cage editing?
The only problem with that is the corners get sharp and I end up with that age old problem of trying to create a smooth corner from three converging surfaces (think set back fillet on basic cube) which is a pain at the best of times.
Is there any other way i can model or deform the inner surface of this shape within Rhino 5 for Mac?
You can see the straight edges on this quick render etc - I’ve tried lofting via cross sections but I always end up with really bad clashing non tangent corners
But… In this case I’ve had to pull the corners to drag them up and down and move them around in plan to model the bubble. I guess I can create the shape using surfaces from curves and then fillet it but I wanted to pull it around to get the best look.
If you want to use fillets/blends, than you are better off simply pulling points on separate surfaces without fillets first. Just make sure you box-select the corner points while pulling.
Start with the inner surfaces. Make cube, explode it. Delete the upper surface. Rebuild 6x6. Move points. When you are done, build the upper surface (_EdgeSrf should suffice). Trim a hole for the neck. Extrude the neck. Even the top points with _SetPt. Join all. Check for naked edges. If there are any, explode or _ExtractSrf, and use _MatchSrf. After you joined everything, use _FilletEdge. Make sure fillets don’t run in each other. Proceed to external surfaces.
You can use _CageEdit later to adjust the overall shape.
That’s what I would do. There could be other approaches as well.
Instead of filleting you can try blending with G2 continuity. Make copies of different variants to see which one looks better.
Filleting and blending is a complex topic, and takes months, if not years, to master. Start here: http://wiki.mcneel.com/rhino/advancedfilleting, and watch every video on YouTube and Vimeo you can find.
On this particular model: explode it, and shrink trimmed surfaces to tidy it up. Join it back. There is one spot that could cause you trouble:
You can extract this surface, and either try to patch it, or use the following trick:
Here I draw a curve on top, snapping to upper angle with End snap, extracted an isocurve on corner surface, and blended them, which gave me a helper curve for _NetworkSrf with G2 continuity:
Yeah, I tried that but if you look at it with zebra or environment map it still has pinch points - I’ve tried several different way to build the surface, what I uploaded was the filleted surface without any trickery from me.
It’s a pain that this sort of thing always requires a work around… 8x in this case
Thanks for the continued tips though, it looks a lot better than when i started!
Hi @2DCube I think I’d not even try to make separate suraces for this - see the attached file - it is a loose loft, with History from some squarish splines - all copies of an orignal that was made against the square. The smaller, inner, copies are rounded off by repeated applications of Smooth (just hold down Enter) . The key is to keep the point object (used at the bottom-center of the loft) coplanar with the next curve- the first ring, to keep the singularity there smooth. You can monkey with the curves to taste- for example, Smooth some points near a corner, directly point edit, etc to mess up the shape, so to speak, to taste. When done, you might want to MatchSrf the top to a revolved or separately modeled neck/rim. You could do exactly the same for the exterior, I just called this one interior because I distorted it so much.
Thank you for that, it’s exactly what I was looking for - hard to break out of the AutoCAD solid modelling way of thinking. I just love the fillet command which is tantamount to laziness.
I’ll post my final render when i’ve done it to close the post
