how to Place a Sphere on top of a hollow cylinder/ cylinder's base touches sphere

[turboCAD]

Hello!

Imagine a basketball sitting on top of a pipe that is half the basketball's diameter: as a result, an inverted dome is comprised within the pipe. The intersection between the cylinder and the pipe is a circle.

How do I place a Cylinder on a Sphere?

I want to be able to move the cylinder and take a point from the sphere where I can attach it(the cylinder).

I will use the sphere as a joint for multiple cylinders so the intersection between a sphere and any cylinder must always be the circle that forms the base of the cylinder NOT another circle parallel to the base(if the cylinder enters the sphere, if you place a metal rod through a snow ball, the resulting object is a bullet, a cylinder with a dome: not what I want).

Please help me if you have the time!

Thank you!

[ReMark]

What are you trying to create using this sphere+cylinder combination?

[MSasu]

I presume that the axis of those cylinders are intersecting the center of the sphere - is this is true, then just make the cylinders a little longer and use their base center point to move on sphere's center. After use copies of the sphere to get the cut on cylinders (SUBTRACT command).

If I missed something in your description, please try to post a sketch of your case.

[ReMark]

Something like this?

[turboCAD]

ReMark: Exactly,yes.

Because I am building a lattice, I will have numerous cylinders and spheres so I need an elegant,repeatable solution to find the same point on the sphere.

MSasu: the centers of the two bases of the cylinder and the sphere's center are collinear so I only need to move the cylinder axially until it touches the sphere but not beyond that point.

[turboCAD]

the sphere is twice the diameter of the base of the cylinder... or x times its diameter, where x may not be rational.

So,basically,I need to find the points(forming a circle) on a sphere where a cylinder would touch but not go through the sphere.

How could I pick a point on the surface of a sphere so that I could connect the quadrant of the cylinder's base to that point?

[turboCAD]

I have what I wanted but the question in the title is still not answered.

method:

- 2 spheres at the desired distance

- 1 line between their centers

- 1 cylinder of desired radius and height equal to the distance between the two spheres' centers

-subtract both spheres from cylinder

-keep the line uniting the centers of the spheres that have been subtracted from the cylinder

This line+concave heads cylinder is the atom of the structure that I can replicate and use with ease for connecting spheres and knowing that the intersection is ALWAYS on the sphere surface and is a perfect circle.

It probably is exactly what MSasu said.

[turboCAD]

the question remains: how could I pick a point from the surface of a Sphere?

The circle has "quadrant"; I would need something equivalent for a sphere. I can see how this is extremely difficult for the software since a sphere is a 3d infinity of circles with quadrants but maybe there is a way:

for instance, if I draw a polyline from the quadrant of the circle that is a base for the cylinder , that line intersects the sphere in two points: where it enters and where it exits. Why can't I locate the intersection point between the polyline and sphere surface(entry) so that I can extrude the cylinder EXACTLY to that point of intersection?

When you connect two cylinders of the same area, base to base, you can put them quadrant to quadrant. Can Autocad recognize that the shape of the cavity in the cylinder matches perfectly the outside convex shape of the sphere such that it could recommend a quadrant of a circle from the sphere that has an identical radius to that of the cylinder base?

[MSasu]

I would build the cylinder from the center of that sphere, adjust the UCS with the origin in the said center and one axis aligned with the axis of the cylinder and after will be very easy to just move the cylinder or to cut it (SLICE command) at the required plane.