Need help finding a solution to this problem

So here it is.
In the grasshopper file im working on I want to extrude the surface of the base shape inwards against its centre and not outwards.

Anyone here with a solution/suggestion to the problem? :)

-Brage

Attachments:

Replies to This Discussion

Permalink Reply by Joseph Oster on July 18, 2015 at 10:24am

Really? No GH file, just a HUGE picture of a complex GH canvas - what kind of answer do you expect?

Can you internalize the data for "the base shape" and leave out all the code extraneous to your question?

Permalink Reply by Brage Hult on July 18, 2015 at 10:33am

Sorry Joseph.
Kinda uploaded in a hurry while continuing to experiment, totally forgot about the gh file (will do right away)

Permalink Reply by Brage Hult on July 18, 2015 at 10:39am

Here it is (GH file)
The Yellow group box marks the base shape.

Attachments:

Shade.gh, 28 KB

Permalink Reply by Joseph Oster on July 18, 2015 at 12:16pm

The 'Loft' component is the base shape, right?

You mention "extrude" but I wonder if you mean you want to "thicken" the base shape? In Rhino, that's done with 'Solid | Offset' but as far as I know, that's not available in GH?

Thickening is a different subject than extruding the base shape (two joined surfaces) in the direction of a vector (i.e., an arbitrary distance between two points), which is easy but not necessarily useful.

One can extrude each of the faces of the brep (base surface) using their respective normal vectors, but that gets you two thick surfaces, not one. I've played around but don't have a general solution for thickening arbitrary breps with non-planar surfaces. Crude experiments attached.

Attachments:

Shade_2015Jul18a.gh, 20 KB

Permalink Reply by Brage Hult on July 18, 2015 at 4:47pm

Thanks for the reply Joseph!
You're correct, what i actually want to is to thicken the base shape.
I'll be experimenting a bit more tomorrow to see if i can find a solution.
But it might look like Pieter has got some sort of solution, that i ought to try out :)

Permalink Reply by Joseph Oster on July 18, 2015 at 5:18pm

Pieter's solution is elegant and correct!

As to how he embedded the image on his canvas, that's under 'File | Export Quick Image' and choose the 3rd icon, 'Viewport Frame'.

Permalink Reply by Pieter Segeren on July 18, 2015 at 2:33pm

Hi Brage,
I would do the offsetting earlier on in the definition, like this for instance:

Attachments:

ThickenInOrOut_PSG.gh, 26 KB

Permalink Reply by Brage Hult on July 18, 2015 at 4:49pm

Nice, and thanks!
I'll try that out tomorrow! :)

P.S. May i ask though, how did you put the model picture into your grasshopper spaghetti? Addon or anything like that?

Permalink Reply by Brage Hult on July 19, 2015 at 5:00am

Pieter!
I have a quick question for you.
In the gh-file you uploaded, you revolved the surface which of course gives rounded edges.
Have you got a suggestion what to do, if i want straight edges. (as in the gh-file i uploaded)
For some reason i'm out of ideas at the moment (probably need to get a cup of coffee before my brain starts working)
Other than that, your gh-file was to much help! :)

Sincerely,

Brage

Permalink Reply by Joseph Oster on July 19, 2015 at 6:30am

Here is a version that extrudes and trims Pieter's lofted cross-section: