Stretch geometry from center line

I am trying to use the polyframe plugin for rhino. I have a bunch of surfaces grouped in an upside down pyramid shape. To get the desired result, I want to stretch the surfaces upwards, but keeping the middle the same:

The form on the right is what I currently have and the one on the right is what I want to get. (more or less-I just made them to illustrate my point).
Here is my file with the surface group.

3. Attach minimal versions of all the relevant files
If you have a gh file you have a question about, attach it to the post. Do not expect that people will recreate a file based on a screen-shot because that’s a lot of pointless work. It’s also a good idea to remove everything non-essential from a gh file. You can use the Internalise Data menu option to cut everything to the left of a parameter.


Ok maybe this was a rhino forum question. I just thought it would be easier to do in grasshopper, but I tried and didn’t get results I was hoping for. Specifically, I did the solidptson command in rhino, tried to collect those points in grasshopper, and move them up, but the points wouldn’t collect as they are only control points. It seems grasshopper doesn’t have a solidpts component so I wasn’t able to proceed.

Thanks, but it seems that that is scaling the whole thing, and I want everything but the middle of the surface to scale.

Like if the shape on the left is the section of the cone you just made, I need to get it like the section on the right.
image (22.3 KB)

Not “stretch geometry” at all, just parametric definition of the shape.

Or use Extr (Extrude Point): (13.6 KB)

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Thanks a lot will try this.

It seems like the grasshopper definition creates the geometry I created in rhino, but what I want to do is stretch existing geometry contained within a pyramid shape into the sort of shape you made.yet another try.3dm (2.4 MB)


yet another try Rhino 5.3dm (4.8 MB)

Stretch geo from center line (8.7 KB)

P.S: This was created before you uploaded the 3dm file.

Check this as well.
stretch (11.1 KB)

Those are great, and you have spent much more time helping me than I would have expected, but ultimately you are just building the shape with moveable parameters. What I need is something that takes the complex geometry I have, and manipulates it in the way you show. If you look on the rhino file you will see that what I have is a lot of surfaces inside a pyramid shape, so somehow I have to get them all stretched uniformly from a center line to get the right result.

@robinharrison the geometry you shared here was having 270 small, small bits of surface. I tried but I couldn’t get the actual result you want

Ok thanks for trying.