Extend a solid like a truncated cone

I try to know how can we do to extend a truncated cone without redraw it.
Thanks for your response,


It depends on what you mean specifically by “extend”.

You can turn on Solid points, select then and drag them around, however, the side angle of the cone will change.

I would like to extend with the same angle.My question is for an other form but the principle is the same,

thanks a lot :slight_smile:

explode the cone and use ExtendSrf on the boundary surface. the angle will stay the same.

Deleting it and making another one is probably the fastest.
If it’s been modified or added to, then @RichardZ’s approach is probably better.

yes but for my project it isn’t a cone, it is more complex piece, so I would like to do en extend with the same angle, thickness …

post the model. You’ll get ‘good’ advice…:panda_face:

So perhaps a sample file or at least a screenshot showing what you are starting from in your original message would have resulted and better suggestion.

please find here the file. I would like to extend in the lower side and keep the angle, thickness

thanks a lot
piece.3dm (3.2 MB)

in this case you have to reconstruct it. it would probably make sense to redraw it. if you are fast in using rhino you can trim off the upper part before the fillet with a curve from a side view and explode the rest. then use ExtendSrf on all flat surfaces separately, dont use this on the round fillets it will fail. after that use sweep 2 on the fillets to fill up the gaps and cut the upper part straight off again since it does not create a fully straight section. then use PlanarSrf to close it and fillet the 2 edges.

thanks a lot I will try,


hello ,

I redite you because I don’t arrive to do it.
It is not possible to planar surf at the below of the piece. Could you please help me again?

thanks a lot,

nicolaspiece.3dm (3.2 MB)

In this case you can use Stretch command.
Don’t worry about what happend on top of the shape, it’s just a preview, only shape in direction you move will be modfied.

Edit : may be this command is not available in Mac version.
Take a look :

thanks but the Stretch command change te angle etc of the piece. So it is not the good way I think???
Could you have a look at the piece2.2
3dm to simplified the curve at the below?
thanks a lotpiece2.3dm (3.5 MB)

What do you mean by simplified the curve at below ?

qu’est ce que tu veux faire exactement ?

bonjour, quand je regarde le bas du dessin, je vois des lignes qui ne sont pas les mêmes qu’au dessus. De plus, je n’arrive pas à créer l’union booléenne des deux partiespiece2.3dm (3.3 MB)

Que tu n’est pas les mêmes lignes, c’est pas très important du moment que tu as les mêmes formes.
Et pour la Booleénne, les surfaces sont tangentes, Rhino a besoin d’une petite “accroche” pour faire son union.
Tu peux soit décaler très légèrement la pièce, soit découper proprement en splitant les surfaces, et joindre.
je pense que la pièce de droite sur ton image a été faite d’un seul bloc , puis découpé, c’est pour ça qu’il y a une continuité dans les lignes.
J’ai fais quelques modifications sur ton fichier, c’est ça que tu cherche a faire ?

piece2-01.3dm (1.1 MB)

Merci pour les informations et le fichier. Le côté droit a été fait avec photoshop pour montrer ce que j’aimerais. En fait je me demande pourquoi il y a tant de lignes qui apparaissent…
Merci pour les astuce,