How to offset a surface & maintain shape?

[ftzuk]

Trying to help in this thread:
Polysurface offset - Grasshopper - McNeel Forum

If I have this surface in other cad software, I can grab these bottom faces and offset them and the software understands that I want that entire shape extended:

How do I do this in Rhino? Offset just pushes those surfaces out straight & I can’t see any offset options to allow this.

surface.3dm (4.8 MB)

[Tom_P]

this kind of solid editing is not supported in rhino as far as i know.
it was wished many times tough.

@ruisantosfortes

It’s not the same. It wouldn’t work if side faces are not vertical

Actually rhino doesn’t even do first option in the picture, only the third that completely distorts the side plane.

Wish for solid editing

In many situations i wish i could manipulate a volume as shown in the gif below, by moving and rotating its faces to cut it. I know this can be done with grasshopper but a native way to do it directly in rhino would be much more convenient. [push faces] Any chance to implement this?

there was newer topics - but i do not find them now.

help on (limited) solid edit:

Edit Solids | Rhino 3-D modeling

[martinsiegrist]

Pushpull… but it only really works on planar surfaces

[Tom_P]

@martinsiegrist

Pushpull

did I miss something ?
_truncatedPyramid
_pushPull top face
ending up with

??

[martinsiegrist]

There’s a command option called ‘Extend’

[Tom_P]

@martinsiegrist

Extend

ok this is the missing step / option - thanks

@ftzuk
_pushPull with extend option might solve your question.

[ftzuk]

Seems like the ‘EXTEND’ option disappears if the surface isn’t planar.

[ftzuk]

It fails even if it is planar depending on the geometry. Cylinder with a straight cut though:

What I expect:

Rhino:

Edit:

Ok Rhino can do that cylinder with the direction option in PushPull. But with something like the geometry in the first post where there isn’t the obvious direction of a cylinder it doesn’t work.