PLANE TANGENT TO MULTIPLE SPHERES.

Hi Dear Grasshopper Users;

I am just wondering how I can generate a plane which is tangent to more than two spheres?

Thanks

Replies to This Discussion

Permalink Reply by Chris Tietjen on June 12, 2013 at 7:49pm

It still needs work.

Attachments:

PlaneTangentTo3Spheres.gh, 15 KB

Permalink Reply by Firat Aydin on June 15, 2013 at 1:50am

it returns with empty parameter but i ll try to work on it

Permalink Reply by Chris Tietjen on June 15, 2013 at 6:02am

It works for me.

Permalink Reply by Firat Aydin on June 15, 2013 at 6:22am

:S interesting... i think some 3rd party plugins corrupted some default attributes of mine. But thanks for your paying attention and your time.

Permalink Reply by Firat Aydin on June 15, 2013 at 5:15am

I just figure out yours was not workin properly. i made some modification. in deed i made some new. but i cannot go further. perhaps it gives you an idea to put an end to this challenge. This problem really bugs me. Thanks for help.

Attachments:

3 SPHERE TANGENT.3dm, 598 KB
3 SPHERE TANGENT.gh, 25 KB

Permalink Reply by Chris Tietjen on June 15, 2013 at 6:20am

Here's the definition again but this time I've connected it to your geometry as per your file posted above.

Attachments:

PlaneTangentTo3Spheres.gh, 18 KB

Permalink Reply by Daniel Piker on June 15, 2013 at 6:08am

Attachments:

tangent_3spheres.gh, 14 KB

Permalink Reply by Daniel Piker on June 15, 2013 at 6:17am

(also note - There are actually 8 tangent planes to a set of 3 spheres, but I'm assuming here it is only the 2 external ones you are interested in)

Permalink Reply by Chris Tietjen on June 15, 2013 at 6:35am

Daniel,
Could you post a screen shot of the definition for those of use not on 0.9.0056?

Thanks.

Permalink Reply by Daniel Piker on June 15, 2013 at 7:45am

Sure:

For 3 circles in 2D (ie the intersection of the spheres with the common plane through their centres) we can take the intersections between each pair of external tangents, and surprisingly they will always lie on a common line.

It's then easy to find the 2 planes which intersect along this line and are tangent to all the spheres.

As a general rule I try to use the mathematical intersections rather than physical wherever possible, as it's my understanding that they tend to be faster and more accurate (though I've never actually tested to see the difference).

Permalink Reply by Chris Tietjen on June 15, 2013 at 8:33am

Nice insight. I wouldn't have seen that in a million years.

Permalink Reply by Firat Aydin on June 16, 2013 at 3:15am

i ve been using RH4 sr9. New release of grasshopper works with only RH5 sr3 min. i think thats y i cannot keep up the pace with you guys. its y your GH definitions are not workin on my computer.