point and sphere :)

Replies to This Discussion

Permalink Reply by Danny Boyes on June 29, 2012 at 11:08am

hi alex, i don't understand the question would you expand it a bit. maybe include a sketch or a file please.

Permalink Reply by Alex on June 29, 2012 at 10:07pm

1,1,1 is the point on the sphere ?!

Attachments:

• point-1_73.bmp, 1 MB

Permalink Reply by Alex on June 29, 2012 at 12:03pm

I can not understand why the point x = 1, y = 1, z = 1 (point2.bmp)
outside the sphere?

Attachments:

• point.bmp, 1.1 MB
• point2.bmp, 1.1 MB

Permalink Reply by wrogirzymian on June 29, 2012 at 2:04pm

Why would it be inside?

Permalink Reply by Brian Harms on June 29, 2012 at 2:27pm

a point at 1,1,1 is about 1.73 units away from 0,0,0. Since 1.73 > sphere radius of 1, it is outside the sphere. 

Points like:

0,0,1

0,1,0

1,0,0

Are all inside the sphere (or rather on the sphere, not sure if that counts).

Permalink Reply by Mateusz Zwierzycki on June 29, 2012 at 2:34pm

they are in sphere surface domain :P

Permalink Reply by Alex on June 29, 2012 at 9:55pm

thanks Brian for the help, but 1,1,1 is the point on the sphere

Permalink Reply by Brian Harms on June 29, 2012 at 10:10pm

the point x = 1, y = 1, z = 1 is neither inside nor on a sphere with an origin of 0,0,0 and a radius of 1. What is it that you are trying to do?

Permalink Reply by Alex on June 29, 2012 at 10:15pm

put a point 1,1,1 on the sphere 

Permalink Reply by Brian Harms on June 29, 2012 at 10:24pm

you can do a variety of things to put a point on a sphere, but you can never have a point at 1,1,1 be on a sphere with a radius of 1 at origin 0,0,0.

You could:

Use brep closest point to find the closest point on the sphere to 1,1,1

draw a line from the origin to 1,1,1 and intersect it with the sphere

use the evaluate surface component to create one or more points on the sphere

etc.

Permalink Reply by Brian Harms on June 29, 2012 at 10:32pm

I'm trying to read between the lines here... maybe you want to create a point from x,y,and z values that creates a sphere with a radius equal to the distance between 0 and the point? like so:

Permalink Reply by Alex on June 29, 2012 at 11:01pm

Brian, thank you for this example (BRep ). This elegant and beautiful solution. Thank you for your help.

• ‹ Previous
• 1
• 2
• Next ›
• Page