Trying to make a hyperbolic paraboloid-esq shape, need help

pilou

What is K-tools?

The best free surface generator I know for some parametric surfaces is k3dsurf

TIG

Crai Depot is busted so here it is...k_tools.rb
(c) Klaudius "mail@klaudiuskrusch.de"

pilou

Thx

Gaieus

@tig said:

Crai Depot is busted so here it is...

For weeks I used to be unable to access the ruby depot, too. It seems to have a new URL now:
http://rhin.crai.archi.fr/RubyLibraryDepot/Ruby/RUBY_Library_Depot.htm

Google doesn't "know" about it yet - although the www version redirects here.

TIG

Thanks, I was wondering what was up

jeff hammond

hey scott..
the problem with using any of these plugins for this type of shape is they are only skinning but not necessarily handling the most difficult part which is making the outlining border..

here's a pretty simple method and you can do it without plugins (though i used two: lathe and booltools)

not so detailed step-by-step

TIG

Jeff

A succinct example of how to use two processes to achieve your goal quickly...

charly2008

Hi,

Yesterday I also tried to construct this part, had then given up because I could not find the right approach. My thinking was so fixated on the extrusion tools by TIG. Nothing against the extrusion tools, but for this case it was the wrong tool choice.

I'm always fascinated how simple processes can solve a problem in Sketchup and this is also a reason why I love this forum.

The method Jeff used allows also to determine the exact dimensions of the geometric shape and it shows again how efficient Sketchup is. Thanks to all who delivered Ideas for solving this process.

Karlheinz

charly2008

Hi,

I have a question. Jeff started from a rectangular base. The shape from farbs looks like a trapezoid base like this one shown below (the saddle shape is made with TIGs EE by Rails).

If i scale the circle in the way like Jeff did it i have in this case a small problem. But how to avoid it? I know I could just delete the protruding edges. But that would not be a correct solution.

pringle_roof-2.skp

jeff hammond

hmm.. maybe you're right.. it's not symmetrical along that axis..

if that's the case, you might want to try the taper tool in FredoScale to get your intersecting oval into more of a guitar pick shape...

exaggerated for illustration purpose

or, you could probably use the taper tool on the skp i posted above and arrive at a similar shape.. (i don't have much time to play with it now.. i'm supposed to be drawing something for work .. must_get_off_the_net)

TIG

OR make the 'saddle' a bit bigger than the ellipsoidal cylinder so that they do fully intersect ?
Why does the initial EEbyRails created 'saddle' have to be 'exactly the same size' as the cutting-shape - it could be a lot bigger, then you could easily erase the unwanted parts with no loss of detail ???

charly2008

Jeff, thanks for your answer. I will try your tips and will present the results here.

Karlheinz

charly2008

Hello TIG,

you're not wrong, so I could do it. But my endeavor was to move within the predetermined dimensions. One is always on the lookout for a better solution. Thanks for your advice.

Karlheinz

charly2008

as Jeff adviced i used Fredos Box Tapering tool to make it fit. The result is now perfectly.

pringle_roof-2.skp

frv

I was trying to use the soapskin & bubble tool but it does only seem to generate a flat surface. After that the tools seem not to have any effect. Maybe someone can help me see what I am doing wrong.
Tx Francois

mac1

@frv said:

I was trying to use the soapskin & bubble tool but it does only seem to generate a flat surface. After that the tools seem not to have any effect. Maybe someone can help me see what I am doing wrong.
Tx Francois

you have to enter pressure values ( neg or pos) to get the surface to inflate