Move sphere tangent to bore

In this example, how do I move the sphere so that its outer surface is touching the top edge bore exactly?

Thanks …

Hello - in this case moving using the Quad osnap for both start and end points should get it onto the top edge - then slide it up and down. To only move the thing sideway, use Quad for the start point and then drag it sideways with Ortho, hit Tab (Tab direction lock) then find the Quad on the top edge of the hole.

This illustrates the latter -

The quad on the sphere is the edge curve - this is on an ‘ortho’ location - it could be more complicated if yours is not lined up that way but it looks like it is.
Of course if they are the same diameter, using the Cen Onsap will do just as well.


I know how to use the QUAD command. The ball is perfectly centered in the hole. The hole is 94.3% of the ball diameter. I want to move the ball, while still being centered (and it was drawn in the center) in the hole, towards the hole ‘until’ the sphere’s outer surface physically touches the edge of the top of the hole (accurately). You know, like when a line is tangent to a circle. I don’t want to eyeball it.

Then that isn’t tangent.

Draw a vertical line from the quad of the cylinder bore to it intersects the sphere.
Move the Sphere from the apparent intersection of the sphere and the line to the edge of the bore.

You could also Project the cylinder onto the sphere in the top viewport.
Then move the sphere from the quad on the projected circle down to the cylinder bore corner.

Turn on snap to end and int and turn the rest off.

In the front view select and slide the sphere vertically (using shift to constrain the motion) until the lower hemisphere intersects the cylinder wall.

Select Move and, for the “from”, in the front view select the Int point between sphere and cylinder on the right side. Then for the “to” move the mouse upward (again using shift to constrain the direction) until the End,Int of the top of the cylinder and the upper face is shown as hit. Release the mouse button.

All done.

Sorry, I don’t understand. I have apparent intersection enable (via Options) but it never confirms an apparent intersection so I gave up. I would like to know how to do this myself. Here’s the file.

tetrahedral_layoutl.3dm (230.6 KB)

In Top view Project the edge of the hole onto the sphere.
Turn on Cen Osnap (if not already on.)
Move and select sphere as object to move.
Point to move from - Cen Osnap of the lower projected edge circle.
Point to move to - Cen Osnap of the hole edge
Delete the projected hole edge circles.

Added - Above is similar to John’s suggestion.

Do you have Int and End in Osnaps enabled?

How do you ‘project’ the edge of the ‘hole’ onto the sphere? I can’t make the selection set.

Yes, I had End and Int enabled.

Finally figured something out. I drew a short line segment at the quadrant of the hole in the +X direction, then used the extend command and extended it to the surface of the sphere. Then moved from the intersection of the line at the sphere, back to the end of the line at the hole quadrant. Seems to be correct.


You don’t want an apparent intersection for this, you want an actual one. Here’s a video (spoiler: not an Oscar nominee):


ps I used Ortho rather than shift in this example.