WISH: Extend Srf


I hope that in Rhino 6 the command “extend srf” functions as well: in an interactive and very functional!


while it looks cool, I believe that this will only work well when the surface has been trimmed farther back than the extension that is being made, or if the surface has a straightforward topology and curvature. It looks to me like a combined untrim + offset on surface + trim. So basically you can already do this in rhino, but it will look less fancy. I am pretty sure that such interfaces require a lot of programming to get right. The question is, do you really need it to get the job done?

Same with the fin wish you posted: just a lot of fancy stuff, but not something you can model otherwise. I’d rather see new functionality being added like 5+ sided curvature continuous patches.


I felt like it was a nice idea, better functional, say more practice.
How did The Edge (a) takes place an extension of this kind?


So it should be corrected …


I see… this seems like a bug to me. It should indeed behave like the corrected image you posted.

What would be helpful, is if multiple edges could be selected at once. Then you practically have similar functionality.


But based on the input that was allowed, the result in Rhino is correct.
(davide is double-posting - more of that answer is in the other thread…)


This is what happens when you extend a trimmed edge:
if you extend the edge (a) this is extended but incorrect, as you can see.
If extend the edge (b) this extends on the contrary, towards the inside of the surface.
extend srf error.3dm (185.0 KB)


The same thing happens with this trimmed surface:


Do you know if cases of this type work best in V6?
Thank you


it kind of works: by dragging out the extension, you get a preview and correct result, however if I type in a value, it extends in negative direction, or in other words it removes something from the surface. This is if the edge is a continous edge. If there is a split somewhere, it seems to run into similar kinds of issues like your image above.


So I understand that it is some bug or a Rhino limit for this type of operations.
As you say, the problem is not in the continuous edges, but in those broken, where there is some discontinuity in the edge. In these cases, the extension is not working properly.

There is much work to do to Rajaa in this direction!


This is what happens extending edge (a) of one unit: a disaster! (Even with the other edge is malfunctioning):


The extension srf command has been greatly improved in Rhino’s wip 6.
I think its usability should be refined.
If you extend a border with a option merge = no, with positive value, the command extends and holds the two separate portions (this is correct).
If it extends with a negative value, the command subtracts the surface portion and does not allow to see the two portions, as if applying a merge for subtraction.
In this case, I think it should keep the two parts and make a sort of split. What do you think?

(Pascal Golay) #14

Yep, I had the same thought. I’ll put it on the list.




(Brian Gillespie) #15

RH-39238 is fixed in the latest WIP


Good job Rajaa! The extended command is improving.
To complete and make it more powerful, there are two other conditions:

  • Extending more than one edge (multiple edges at a time)
  • extend edges for polysurfaces.

I do not know if these two aspects might be taken into consideration, in any case you are doing your best!


Still problems with this command…
If you extend the border © with the option “join = no”, it’s ok.
If extending the edges (a) and (b) the command merges everything into a single surface (the option “join = no” is not recognized).

Also, why can extend the edge (a) only to a certain point? Who or what determines the extension limit? (in fact, by moving the cursor to a certain point this disappears, as well as disappearing the preview that highlights the possible extension).
extend srf problem.3dm (47.1 KB)


Rajaa great work on this command, a real boost to V5.
Could you add an “extend for multiple edges” option? (even for trimmed surfaces).
It would be convenient to extend more than one edge simultaneously to a surface …
Asking too much?

Thank you


Nothing answer? :frowning:


i know this feeling … :joy: