Peter Stavnshøj's Page

Peter Stavnshøj joined David Rutten's group

Galapagos

Galapagos Evolutionary Solver

Aug 21, 2012

Peter Stavnshøj posted a discussion

Split open brep with multiple curves???

HiI'm trying to split a joined list of surfaces by a list of curves but I cannot find a component that does that. Basically, I just want to perform the same as the Surface Split component, which doesn't work with open brep...I know that I can extrude the curves and then use split the brep with multiple breps (which would work in this 2D situation) but I'm looking for general procedure for when there isn't an obvious direction for the extrusion...Any suggestions? //PeterSee More

Aug 13, 2012

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Peter Stavnshøj replied to Peter Stavnshøj's discussion What kind of surface do I get from "4 point surface"???

"No, that's true - you need some kind of boundary condition"

Jul 20, 2012

Daniel Piker replied to Peter Stavnshøj's discussion What kind of surface do I get from "4 point surface"???

"I'm not really sure how one would define a minimal surface from 4 points only without also setting the edge curves. If you think of a soap film (which does approximate a minimal surface), attaching to only points doesn't work to make a…"

Jul 20, 2012

Peter Stavnshøj replied to Peter Stavnshøj's discussion What kind of surface do I get from "4 point surface"???

"Sorry, my bad - in my mind I'd already asked for the math, which I obviously didn't... Ok, the math is, as you say, horrible - but I guess I got what I asked for ;) Thanks! One question though - It's a NURBS surface, but is there…"

Jul 20, 2012

Peter Stavnshøj replied to Peter Stavnshøj's discussion What kind of surface do I get from "4 point surface"???

"I did a test yesterday - and "4 point surface" on the points (0,0,0) (1,0,1) (1,1,0) and (1,0,1) - thats a square in xy plan, where the 1st and 3rd point has z=0 and 2nd and 4th point has z=1 - and that did create a hyperbolic paraboloid."

Jul 20, 2012

Danny Boyes replied to Peter Stavnshøj's discussion What kind of surface do I get from "4 point surface"???

"Again? I have not seen you ask this question before. The answer is NURBS - non-uniform rational B-splines Surfaces The horrible maths is a tensor product that looks like this: where Do you apply your FEA to Surfaces or Meshes made from…"

Jul 20, 2012

David Rutten replied to Peter Stavnshøj's discussion What kind of surface do I get from "4 point surface"???

"I think the technical definition of a surface like this is that it is a portion of a hyperbolic paraboloid. Or maybe a parabolic hyperboloid, I can never keep those apart. -- David Rutten david@mcneel.com Poprad, Slovakia"

Jul 20, 2012

Peter Stavnshøj replied to Peter Stavnshøj's discussion What kind of surface do I get from "4 point surface"???

"Alright :D"

Jul 20, 2012

Michael Pryor replied to Peter Stavnshøj's discussion What kind of surface do I get from "4 point surface"???

"I removed that quote as I was not thinking when I wrote it. It is false"

Jul 20, 2012

Peter Stavnshøj replied to Peter Stavnshøj's discussion What kind of surface do I get from "4 point surface"???

"thx Michael, The comment was related to - why have the component "4 point surface" if it delivers the same result as "loft" when governed by the same boundary conditions, i.e.: "4 point surface" = 4 points ->…"

Jul 20, 2012

Michael Pryor replied to Peter Stavnshøj's discussion What kind of surface do I get from "4 point surface"???

"Why not use loft instead? well this depends how your data is structure, most obviously maybe you have 4 points or you have 2 lines. In this case all loft settings will have the same results as a surface from 4 points will always have straight edges…"

Jul 20, 2012

Peter Stavnshøj replied to Peter Stavnshøj's discussion What kind of surface do I get from "4 point surface"???

"Hi Ok, so its not a minimal surface ;) And I know its just a planar surface if the four points are in the same plane. But my question is related to the mathematical expression behind the component. The reason why I thought it was…"

Jul 20, 2012

Danny Boyes replied to Peter Stavnshøj's discussion What kind of surface do I get from "4 point surface"???

"It is either a non-planar or planar untrimmed surface. But it is definitely not a minimal surface."

Jul 19, 2012

Michael Pryor replied to Peter Stavnshøj's discussion What kind of surface do I get from "4 point surface"???

"its not a minimal surface, think of it as a loft between 2 lines."

Jul 19, 2012

Peter Stavnshøj posted a discussion

What kind of surface do I get from "4 point surface"???

HiAs the title say - when you use the "4 point surface" component, you get the a surface governed by the four boundary lines that span between the points you feed the component.But what kind of surface is it? especially, is it the minimal surface? Best, PeterSee More

Jul 19, 2012

13 Comments