This is so cool. visose - it is incredible that you can create this
things. I am quite new to this forum and to GH but I couldn't resist
trying the mathsurfaces, and it's really a matter of copy and paste
from K3DSurf, even though in some cases I haven't figured out how to
set the proper range.

Anyway I tried to follow your solution for the Schwarz surface but I
wanted to ask 2 things.

As you can see in this screenshot: 
http://picasaweb.google.se/lh/photo/RpDHwCRaBECD3718zd2PNg
I didn't know what the first and last parts where, so I set the first
interval to A:-4 B:4, I think I got the other parts right, but could I
ask what the last part is?

/Lars

On 21 Nov, 15:06, visose <[EMAIL PROTECTED]> wrote:
> I'm not sure what would be the best way to create isosurfaces in
> grasshopper (I just learned about them).
> The simplest way to visualize this shape would be to create a 3D grid
> of points that range from -4 to 4 in the 3 axis and then cull this
> list of points using the expression cos(x)+cos(y)+cos(z)< 0, since the
> points that lie inside the volume will result in < 0. The points
> oustide the volume will result in > 0 and the points that lie in the
> exact boundary of the surface will result in = 0.
> This will create a point cloud that will appear to have that shape
> with just a couple of components.
>
> If you want to find out the boundary, you have to "solve for x".
> This is what i did:http://grasshopper3d.googlegroups.com/web/schwartz.jpg
> Since there are 3 variables, I create a 2D grid of points in the XY
> plane that already gives me 2 of the variables, and then I solve for
> the third one.
> The problem is that the third point may have more than one solution,
> but grasshopper only solves for one of them, so it results in
> something similar to the "drape surface" command in rhino.
> What I do is "drape" four 2d grids of points each on a different side
> of the object. What I get is a list of points that lie in the surface
> of the object.
> I don't know if there is an elegant way of constructing this with nurb
> surfaces. Meshing would probably be better.
>
> - Btw there's a part of the definition not shown on the screenshot
> that creates lines between all the points and filters the ones that
> are over a given length, I don't recommend using this.
>
> On Nov 21, 9:56 am, rpict <[EMAIL PROTECTED]> wrote:
>
> > thanks alot visose for sharing the mathsurfaces stuff.
>
> > there are a lot more formulas in explicit polar coordinates within the
> > k3dsurf package.
> > you can just paste and copy them into grasshopper mathsurfaces. also
> > the klein bottle works :)
>
> > X():(3*(1+sin(v)) + 2*(1-cos(v)/2)*cos(u))*cos(v)
> > Y():(4+2*(1-cos(v)/2)*cos(u))*sin(v)
> > Z():-2*(1-cos(v)/2) * sin(u)
> > [u]:0,  2*pi
> > [v]:0,  2*pi
>
> >http://k3dsurf.sourceforge.net/
>
> > this leads me to another question:
> > the k3dsurf package contents also isosurfaces in cartesian coordinates
> > F(x,y,z,t....)=0
> > e.g. the Schwartz surface: cos(x)+cos(y)+cos(z)=0;  x,y,z=(-4,4)
> > does anyone know how to set up mathsurfaces in this format?
>
> > -rpict

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